[PATCH 0/3] log --graph and rev-list --graph

[PATCH 0/3] log --graph and rev-list --graph

[Adam Simpkins]

This patch series adds a new --graph option to the log and rev-list
commands.  This is pretty much the same code that I sent out in early
April, but updated to work with the log entry termination fixes in the
latest master branch.

Adam Simpkins (3):
  revision API: split parent rewriting and parent printing options
  Add history graph API
  log and rev-list: add --graph option

 Documentation/rev-list-options.txt            |   10 +
 Documentation/technical/api-history-graph.txt |  179 +++++
 Makefile                                      |    2 +
 builtin-rev-list.c                            |   52 ++-
 graph.c                                       |  903 +++++++++++++++++++++++++
 graph.h                                       |  121 ++++
 log-tree.c                                    |   80 ++-
 revision.c                                    |   33 +-
 revision.h                                    |    9 +-
 9 files changed, 1369 insertions(+), 20 deletions(-)
 create mode 100644 Documentation/technical/api-history-graph.txt
 create mode 100644 graph.c
 create mode 100644 graph.h

[PATCH 1/3] revision API: split parent rewriting and parent printing options

[Adam Simpkins]

This change allows parent rewriting to be performed without causing
the log and rev-list commands to print the parents.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
---
 builtin-rev-list.c |    2 +-
 log-tree.c         |    4 ++--
 revision.c         |    7 ++++---
 revision.h         |    3 ++-
 4 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index edc0bd3..476a870 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -77,7 +77,7 @@ static void show_commit(struct commit *commit)
 		      stdout);
 	else
 		fputs(sha1_to_hex(commit->object.sha1), stdout);
-	if (revs.parents) {
+	if (revs.print_parents) {
 		struct commit_list *parents = commit->parents;
 		while (parents) {
 			printf(" %s", sha1_to_hex(parents->item->object.sha1));
diff --git a/log-tree.c b/log-tree.c
index d3fb0e5..74829d7 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -231,7 +231,7 @@ void show_log(struct rev_info *opt)
 				putchar('>');
 		}
 		fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit), stdout);
-		if (opt->parents)
+		if (opt->print_parents)
 			show_parents(commit, abbrev_commit);
 		show_decorations(commit);
 		putchar(opt->diffopt.line_termination);
@@ -271,7 +271,7 @@ void show_log(struct rev_info *opt)
 		}
 		fputs(diff_unique_abbrev(commit->object.sha1, abbrev_commit),
 		      stdout);
-		if (opt->parents)
+		if (opt->print_parents)
 			show_parents(commit, abbrev_commit);
 		if (parent)
 			printf(" (from %s)",
diff --git a/revision.c b/revision.c
index 4231ea2..a813304 100644
--- a/revision.c
+++ b/revision.c
@@ -1105,7 +1105,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				}
 			}
 			if (!strcmp(arg, "--parents")) {
-				revs->parents = 1;
+				revs->rewrite_parents = 1;
+				revs->print_parents = 1;
 				continue;
 			}
 			if (!strcmp(arg, "--dense")) {
@@ -1524,13 +1525,13 @@ enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
 		/* Commit without changes? */
 		if (commit->object.flags & TREESAME) {
 			/* drop merges unless we want parenthood */
-			if (!revs->parents)
+			if (!revs->rewrite_parents)
 				return commit_ignore;
 			/* non-merge - always ignore it */
 			if (!commit->parents || !commit->parents->next)
 				return commit_ignore;
 		}
-		if (revs->parents && rewrite_parents(revs, commit) < 0)
+		if (revs->rewrite_parents && rewrite_parents(revs, commit) < 0)
 			return commit_error;
 	}
 	return commit_show;
diff --git a/revision.h b/revision.h
index 31217f8..201bd97 100644
--- a/revision.h
+++ b/revision.h
@@ -46,7 +46,8 @@ struct rev_info {
 			unpacked:1, /* see also ignore_packed below */
 			boundary:2,
 			left_right:1,
-			parents:1,
+			rewrite_parents:1,
+			print_parents:1,
 			reverse:1,
 			cherry_pick:1,
 			first_parent_only:1;
-- 
1.5.5.1.128.gc15ea

[PATCH 2/3] Add history graph API

[Adam Simpkins]

This new API allows the commit history to be displayed as a text-based
graphical representation.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
---
 Documentation/technical/api-history-graph.txt |  176 +++++
 Makefile                                      |    2 +
 graph.c                                       |  903 +++++++++++++++++++++++++
 graph.h                                       |  121 ++++
 4 files changed, 1202 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/technical/api-history-graph.txt
 create mode 100644 graph.c
 create mode 100644 graph.h

diff --git a/Documentation/technical/api-history-graph.txt b/Documentation/technical/api-history-graph.txt
new file mode 100644
index 0000000..5f6465f
--- /dev/null
+++ b/Documentation/technical/api-history-graph.txt
@@ -0,0 +1,176 @@
+history graph API
+=================
+
+The graph API is used to draw a text-based representation of the commit
+history.  The API generates the graph in a line-by-line fashion.
+
+Functions
+---------
+
+Core functions:
+
+* `graph_init()` creates a new `struct git_graph`
+
+* `graph_release()` destroys a `struct git_graph`, and frees the memory
+  associated with it.
+
+* `graph_update()` moves the graph to a new commit.
+
+* `graph_next_line()` outputs the next line of the graph into a strbuf.  It
+  does not add a terminating newline.
+
+* `graph_padding_line()` outputs a line of vertical padding in the graph.  It
+  is similar to `graph_next_line()`, but is guaranteed to never print the line
+  containing the current commit.  Where `graph_next_line()` would print the
+  commit line next, `graph_padding_line()` prints a line that simply extends
+  all branch lines downwards one row, leaving their positions unchanged.
+
+* `graph_is_commit_finished()` determines if the graph has output all lines
+  necessary for the current commit.  If `graph_update()` is called before all
+  lines for the current commit have been printed, the next call to
+  `graph_next_line()` will output an ellipsis, to indicate that a portion of
+  the graph was omitted.
+
+The following utility functions are wrappers around `graph_next_line()` and
+`graph_is_commit_finished()`.  They always print the output to stdout.
+They can all be called with a NULL graph argument, in which case no graph
+output will be printed.
+
+* `graph_show_commit()` calls `graph_next_line()` until it returns non-zero.
+  This prints all graph lines up to, and including, the line containing this
+  commit.  Output is printed to stdout.  The last line printed does not contain
+  a terminating newline.  This should not be called if the commit line has
+  already been printed, or it will loop forever.
+
+* `graph_show_oneline()` calls `graph_next_line()` and prints the result to
+  stdout.  The line printed does not contain a terminating newline.
+
+* `graph_show_padding()` calls `graph_padding_line()` and prints the result to
+  stdout.  The line printed does not contain a terminating newline.
+
+* `graph_show_remainder()` calls `graph_next_line()` until
+  `graph_is_commit_finished()` returns non-zero.  Output is printed to stdout.
+  The last line printed does not contain a terminating newline.  Returns 1 if
+  output was printed, and 0 if no output was necessary.
+
+* `graph_show_strbuf()` prints the specified strbuf to stdout, prefixing all
+  lines but the first with a graph line.  The caller is responsible for
+  ensuring graph output for the first line has already been printed to stdout.
+  (This can be done with `graph_show_commit()` or `graph_show_oneline()`.)  If
+  a NULL graph is supplied, the strbuf is printed as-is.
+
+* `graph_show_commit_msg()` is similar to `graph_show_strbuf()`, but it also
+  prints the remainder of the graph, if more lines are needed after the strbuf
+  ends.  It is better than directly calling `graph_show_strbuf()` followed by
+  `graph_show_remainder()` since it properly handles buffers that do not end in
+  a terminating newline.  The output printed by `graph_show_commit_msg()` will
+  end in a newline if and only if the strbuf ends in a newline.
+
+Data structure
+--------------
+`struct git_graph` is an opaque data type used to store the current graph
+state.
+
+Calling sequence
+----------------
+
+* Create a `struct git_graph` by calling `graph_init()`.
+
+* Use the revision walking API to walk through a group of contiguous commits.
+
+* For each commit traversed, call `graph_update()` to move the graph to the
+  next commit.  Once `graph_update()` has been called, call `graph_next_line()`
+  repeatedly, until `graph_is_commit_finished()` returns non-zero.  Each call
+  to `graph_next_line()` will output a single line of the graph.  The resulting
+  lines will not contain any newlines.  `graph_next_line()` returns 1 if the
+  resulting line contains the current commit, or 0 if this is merely a line
+  needed to adjust the graph before or after the current commit.  This return
+  value can be used to determine where to print the commit summary information
+  alongside the graph output.
+
+Limitations
+-----------
+
+* `graph_update()` must be called with commits in topological order.  It should
+  not be called on a commit if it has already been invoked with an ancestor of
+  that commit, or the graph output will be incorrect.
+
+* `graph_update()` must be called on a contiguous group of commits.  If
+  `graph_update()` is called on a particular commit, it should later be called
+  on all parents of that commit.  Parents must not be skipped, or the graph
+  output will appear incorrect.
++
+`graph_update()` may be used on a pruned set of commits only if the parent list
+has been rewritten so as to include only ancestors from the pruned set.
+
+* The graph API does not currently support reverse commit ordering.  In
+  order to implement reverse ordering, the graphing API needs an
+  (efficient) mechanism to find the children of a commit.
+
+Sample usage
+------------
+
+------------
+struct commit *commit;
+struct git_graph *graph = graph_init();
+
+while ((commit = get_revision(opts)) != NULL) {
+	graph_update(graph, commit);
+	while (!graph_is_commit_finished(graph))
+	{
+		struct strbuf sb;
+		int is_commit_line;
+
+		strbuf_init(&sb, 0);
+		is_commit_line = graph_next_line(graph, &sb);
+		fputs(sb.buf, stdout);
+
+		if (is_commit_line)
+			log_tree_commit(opts, commit);
+		else
+			putchar(opts->diffopt.line_termination);
+	}
+}
+
+graph_release(graph);
+------------
+
+Sample output
+-------------
+
+The following is an example of the output from the graph API.  This output does
+not include any commit summary information--callers are responsible for
+outputting that information, if desired.
+
+------------
+*
+*
+M
+|\
+* |
+| | *
+| \ \
+|  \ \
+M-. \ \
+|\ \ \ \
+| | * | |
+| | | | | *
+| | | | | *
+| | | | | M
+| | | | | |\
+| | | | | | *
+| * | | | | |
+| | | | | M  \
+| | | | | |\  |
+| | | | * | | |
+| | | | * | | |
+* | | | | | | |
+| |/ / / / / /
+|/| / / / / /
+* | | | | | |
+|/ / / / / /
+* | | | | |
+| | | | | *
+| | | | |/
+| | | | *
+------------
diff --git a/Makefile b/Makefile
index 9d84c8d..d42b117 100644
--- a/Makefile
+++ b/Makefile
@@ -346,6 +346,7 @@ LIB_H += diff.h
 LIB_H += dir.h
 LIB_H += fsck.h
 LIB_H += git-compat-util.h
+LIB_H += graph.h
 LIB_H += grep.h
 LIB_H += hash.h
 LIB_H += list-objects.h
@@ -411,6 +412,7 @@ LIB_OBJS += entry.o
 LIB_OBJS += environment.o
 LIB_OBJS += exec_cmd.o
 LIB_OBJS += fsck.o
+LIB_OBJS += graph.o
 LIB_OBJS += grep.o
 LIB_OBJS += hash.o
 LIB_OBJS += help.o
diff --git a/graph.c b/graph.c
new file mode 100644
index 0000000..b575d10
--- /dev/null
+++ b/graph.c
@@ -0,0 +1,903 @@
+#include "cache.h"
+#include "commit.h"
+#include "graph.h"
+#include "diff.h"
+#include "revision.h"
+
+/*
+ * TODO:
+ * - Add colors to the graph.
+ *   Pick a color for each column, and print all characters
+ *   in that column with the specified color.
+ *
+ * - Limit the number of columns, similar to the way gitk does.
+ *   If we reach more than a specified number of columns, omit
+ *   sections of some columns.
+ *
+ * - The output during the GRAPH_PRE_COMMIT and GRAPH_COLLAPSING states
+ *   could be made more compact by printing horizontal lines, instead of
+ *   long diagonal lines.  For example, during collapsing, something like
+ *   this:          instead of this:
+ *   | | | | |      | | | | |
+ *   | |_|_|/       | | | |/
+ *   |/| | |        | | |/|
+ *   | | | |        | |/| |
+ *                  |/| | |
+ *                  | | | |
+ *
+ *   If there are several parallel diagonal lines, they will need to be
+ *   replaced with horizontal lines on subsequent rows.
+ */
+
+struct column {
+	/*
+	 * The parent commit of this column.
+	 */
+	struct commit *commit;
+	/*
+	 * XXX: Once we add support for colors, struct column could also
+	 * contain the color of its branch line.
+	 */
+};
+
+enum graph_state {
+	GRAPH_PADDING,
+	GRAPH_SKIP,
+	GRAPH_PRE_COMMIT,
+	GRAPH_COMMIT,
+	GRAPH_POST_MERGE,
+	GRAPH_COLLAPSING
+};
+
+struct git_graph {
+	/*
+	 * The commit currently being processed
+	 */
+	struct commit *commit;
+	/*
+	 * The number of parents this commit has.
+	 * (Stored so we don't have to walk over them each time we need
+	 * this number)
+	 */
+	int num_parents;
+	/*
+	 * The next expansion row to print
+	 * when state is GRAPH_PRE_COMMIT
+	 */
+	int expansion_row;
+	/*
+	 * The current output state.
+	 * This tells us what kind of line graph_next_line() should output.
+	 */
+	enum graph_state state;
+	/*
+	 * The maximum number of columns that can be stored in the columns
+	 * and new_columns arrays.  This is also half the number of entries
+	 * that can be stored in the mapping and new_mapping arrays.
+	 */
+	int column_capacity;
+	/*
+	 * The number of columns (also called "branch lines" in some places)
+	 */
+	int num_columns;
+	/*
+	 * The number of columns in the new_columns array
+	 */
+	int num_new_columns;
+	/*
+	 * The number of entries in the mapping array
+	 */
+	int mapping_size;
+	/*
+	 * The column state before we output the current commit.
+	 */
+	struct column *columns;
+	/*
+	 * The new column state after we output the current commit.
+	 * Only valid when state is GRAPH_COLLAPSING.
+	 */
+	struct column *new_columns;
+	/*
+	 * An array that tracks the current state of each
+	 * character in the output line during state GRAPH_COLLAPSING.
+	 * Each entry is -1 if this character is empty, or a non-negative
+	 * integer if the character contains a branch line.  The value of
+	 * the integer indicates the target position for this branch line.
+	 * (I.e., this array maps the current column positions to their
+	 * desired positions.)
+	 *
+	 * The maximum capacity of this array is always
+	 * sizeof(int) * 2 * column_capacity.
+	 */
+	int *mapping;
+	/*
+	 * A temporary array for computing the next mapping state
+	 * while we are outputting a mapping line.  This is stored as part
+	 * of the git_graph simply so we don't have to allocate a new
+	 * temporary array each time we have to output a collapsing line.
+	 */
+	int *new_mapping;
+};
+
+struct git_graph *graph_init()
+{
+	struct git_graph *graph = xmalloc(sizeof(struct git_graph));
+	graph->commit = NULL;
+	graph->num_parents = 0;
+	graph->expansion_row = 0;
+	graph->state = GRAPH_PADDING;
+	graph->num_columns = 0;
+	graph->num_new_columns = 0;
+	graph->mapping_size = 0;
+
+	/*
+	 * Allocate a reasonably large default number of columns
+	 * We'll automatically grow columns later if we need more room.
+	 */
+	graph->column_capacity = 30;
+	graph->columns = xmalloc(sizeof(struct column) *
+				 graph->column_capacity);
+	graph->new_columns = xmalloc(sizeof(struct column) *
+				     graph->column_capacity);
+	graph->mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
+	graph->new_mapping = xmalloc(sizeof(int) * 2 * graph->column_capacity);
+
+	return graph;
+}
+
+void graph_release(struct git_graph *graph)
+{
+	free(graph->columns);
+	free(graph->new_columns);
+	free(graph->mapping);
+	free(graph);
+}
+
+static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
+{
+	if (graph->column_capacity >= num_columns)
+		return;
+
+	do {
+		graph->column_capacity *= 2;
+	} while (graph->column_capacity < num_columns);
+
+	graph->columns = xrealloc(graph->columns,
+				  sizeof(struct column) *
+				  graph->column_capacity);
+	graph->new_columns = xrealloc(graph->new_columns,
+				      sizeof(struct column) *
+				      graph->column_capacity);
+	graph->mapping = xrealloc(graph->mapping,
+				  sizeof(int) * 2 * graph->column_capacity);
+	graph->new_mapping = xrealloc(graph->new_mapping,
+				      sizeof(int) * 2 * graph->column_capacity);
+}
+
+static void graph_insert_into_new_columns(struct git_graph *graph,
+					  struct commit *commit,
+					  int *mapping_index)
+{
+	int i;
+
+	/*
+	 * Ignore uinteresting and pruned commits
+	 */
+	if (commit->object.flags & (UNINTERESTING | TREESAME))
+		return;
+
+	/*
+	 * If the commit is already in the new_columns list, we don't need to
+	 * add it.  Just update the mapping correctly.
+	 */
+	for (i = 0; i < graph->num_new_columns; i++) {
+		if (graph->new_columns[i].commit == commit) {
+			graph->mapping[*mapping_index] = i;
+			*mapping_index += 2;
+			return;
+		}
+	}
+
+	/*
+	 * This commit isn't already in new_columns.  Add it.
+	 */
+	graph->new_columns[graph->num_new_columns].commit = commit;
+	graph->mapping[*mapping_index] = graph->num_new_columns;
+	*mapping_index += 2;
+	graph->num_new_columns++;
+}
+
+static void graph_update_columns(struct git_graph *graph)
+{
+	struct commit_list *parent;
+	struct column *tmp_columns;
+	int max_new_columns;
+	int mapping_idx;
+	int i, seen_this;
+
+	/*
+	 * Swap graph->columns with graph->new_columns
+	 * graph->columns contains the state for the previous commit,
+	 * and new_columns now contains the state for our commit.
+	 *
+	 * We'll re-use the old columns array as storage to compute the new
+	 * columns list for the commit after this one.
+	 */
+	tmp_columns = graph->columns;
+	graph->columns = graph->new_columns;
+	graph->num_columns = graph->num_new_columns;
+
+	graph->new_columns = tmp_columns;
+	graph->num_new_columns = 0;
+
+	/*
+	 * Now update new_columns and mapping with the information for the
+	 * commit after this one.
+	 *
+	 * First, make sure we have enough room.  At most, there will
+	 * be graph->num_columns + graph->num_parents columns for the next
+	 * commit.
+	 */
+	max_new_columns = graph->num_columns + graph->num_parents;
+	graph_ensure_capacity(graph, max_new_columns);
+
+	/*
+	 * Clear out graph->mapping
+	 */
+	graph->mapping_size = 2 * max_new_columns;
+	for (i = 0; i < graph->mapping_size; i++)
+		graph->mapping[i] = -1;
+
+	/*
+	 * Populate graph->new_columns and graph->mapping
+	 *
+	 * Some of the parents of this commit may already be in
+	 * graph->columns.  If so, graph->new_columns should only contain a
+	 * single entry for each such commit.  graph->mapping should
+	 * contain information about where each current branch line is
+	 * supposed to end up after the collapsing is performed.
+	 */
+	seen_this = 0;
+	mapping_idx = 0;
+	for (i = 0; i <= graph->num_columns; i++) {
+		struct commit *col_commit;
+		if (i == graph->num_columns) {
+			if (seen_this)
+				break;
+			col_commit = graph->commit;
+		} else {
+			col_commit = graph->columns[i].commit;
+		}
+
+		if (col_commit == graph->commit) {
+			seen_this = 1;
+			for (parent = graph->commit->parents;
+			     parent;
+			     parent = parent->next) {
+				graph_insert_into_new_columns(graph,
+							      parent->item,
+							      &mapping_idx);
+			}
+		} else {
+			graph_insert_into_new_columns(graph, col_commit,
+						      &mapping_idx);
+		}
+	}
+
+	/*
+	 * Shrink mapping_size to be the minimum necessary
+	 */
+	while (graph->mapping_size > 1 &&
+	       graph->mapping[graph->mapping_size - 1] < 0)
+		graph->mapping_size--;
+}
+
+void graph_update(struct git_graph *graph, struct commit *commit)
+{
+	struct commit_list *parent;
+
+	/*
+	 * Set the new commit
+	 */
+	graph->commit = commit;
+
+	/*
+	 * Count how many parents this commit has
+	 */
+	graph->num_parents = 0;
+	for (parent = commit->parents; parent; parent = parent->next)
+		graph->num_parents++;
+
+	/*
+	 * Call graph_update_columns() to update
+	 * columns, new_columns, and mapping.
+	 */
+	graph_update_columns(graph);
+
+	graph->expansion_row = 0;
+
+	/*
+	 * Update graph->state.
+	 *
+	 * If the previous commit didn't get to the GRAPH_PADDING state,
+	 * it never finished its output.  Goto GRAPH_SKIP, to print out
+	 * a line to indicate that portion of the graph is missing.
+	 *
+	 * Otherwise, if there are 3 or more parents, we need to print
+	 * extra rows before the commit, to expand the branch lines around
+	 * it and make room for it.
+	 *
+	 * If there are less than 3 parents, we can immediately print the
+	 * commit line.
+	 */
+	if (graph->state != GRAPH_PADDING)
+		graph->state = GRAPH_SKIP;
+	else if (graph->num_parents >= 3)
+		graph->state = GRAPH_PRE_COMMIT;
+	else
+		graph->state = GRAPH_COMMIT;
+}
+
+static int graph_is_mapping_correct(struct git_graph *graph)
+{
+	int i;
+
+	/*
+	 * The mapping is up to date if each entry is at its target,
+	 * or is 1 greater than its target.
+	 * (If it is 1 greater than the target, '/' will be printed, so it
+	 * will look correct on the next row.)
+	 */
+	for (i = 0; i < graph->mapping_size; i++) {
+		int target = graph->mapping[i];
+		if (target < 0)
+			continue;
+		if (target == (i / 2))
+			continue;
+		return 0;
+	}
+
+	return 1;
+}
+
+static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
+{
+	/*
+	 * Add additional spaces to the end of the strbuf, so that all
+	 * lines for a particular commit have the same width.
+	 *
+	 * This way, fields printed to the right of the graph will remain
+	 * aligned for the entire commit.
+	 *
+	 * This computation results in 3 extra space to the right in most
+	 * cases, but only 1 extra space if the commit doesn't have any
+	 * children that have already been displayed in the graph (i.e.,
+	 * if the current commit isn't in graph->columns).
+	 */
+	size_t extra;
+	size_t final_width = graph->num_columns + graph->num_parents;
+	if (graph->num_parents < 1)
+		final_width++;
+	final_width *= 2;
+
+	if (sb->len >= final_width)
+		return;
+
+	extra = final_width - sb->len;
+	strbuf_addf(sb, "%*s", extra, "");
+}
+
+static void graph_output_padding_line(struct git_graph *graph,
+				      struct strbuf *sb)
+{
+	int i;
+
+	/*
+	 * We could conceivable be called with a NULL commit
+	 * if our caller has a bug, and invokes graph_next_line()
+	 * immediately after graph_init(), without first calling
+	 * graph_update().  Return without outputting anything in this
+	 * case.
+	 */
+	if (!graph->commit)
+		return;
+
+	/*
+	 * Output a padding row, that leaves all branch lines unchanged
+	 */
+	for (i = 0; i < graph->num_new_columns; i++) {
+		strbuf_addstr(sb, "| ");
+	}
+
+	graph_pad_horizontally(graph, sb);
+}
+
+static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
+{
+	/*
+	 * Output an ellipsis to indicate that a portion
+	 * of the graph is missing.
+	 */
+	strbuf_addstr(sb, "...");
+	graph_pad_horizontally(graph, sb);
+
+	if (graph->num_parents >= 3)
+		graph->state = GRAPH_PRE_COMMIT;
+	else
+		graph->state = GRAPH_COMMIT;
+}
+
+static void graph_output_pre_commit_line(struct git_graph *graph,
+					 struct strbuf *sb)
+{
+	int num_expansion_rows;
+	int i, seen_this;
+
+	/*
+	 * This function formats a row that increases the space around a commit
+	 * with multiple parents, to make room for it.  It should only be
+	 * called when there are 3 or more parents.
+	 *
+	 * We need 2 extra rows for every parent over 2.
+	 */
+	assert(graph->num_parents >= 3);
+	num_expansion_rows = (graph->num_parents - 2) * 2;
+
+	/*
+	 * graph->expansion_row tracks the current expansion row we are on.
+	 * It should be in the range [0, num_expansion_rows - 1]
+	 */
+	assert(0 <= graph->expansion_row &&
+	       graph->expansion_row < num_expansion_rows);
+
+	/*
+	 * Output the row
+	 */
+	seen_this = 0;
+	for (i = 0; i < graph->num_columns; i++) {
+		struct column *col = &graph->columns[i];
+		if (col->commit == graph->commit) {
+			seen_this = 1;
+			strbuf_addf(sb, "| %*s", graph->expansion_row, "");
+		} else if (seen_this) {
+			strbuf_addstr(sb, "\\ ");
+		} else {
+			strbuf_addstr(sb, "| ");
+		}
+	}
+
+	graph_pad_horizontally(graph, sb);
+
+	/*
+	 * Increment graph->expansion_row,
+	 * and move to state GRAPH_COMMIT if necessary
+	 */
+	graph->expansion_row++;
+	if (graph->expansion_row >= num_expansion_rows)
+		graph->state = GRAPH_COMMIT;
+}
+
+void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
+{
+	int seen_this = 0;
+	int i, j;
+
+	/*
+	 * Output the row containing this commit
+	 * Iterate up to and including graph->num_columns,
+	 * since the current commit may not be in any of the existing
+	 * columns.  (This happens when the current commit doesn't have any
+	 * children that we have already processed.)
+	 */
+	seen_this = 0;
+	for (i = 0; i <= graph->num_columns; i++) {
+		struct commit *col_commit;
+		if (i == graph->num_columns) {
+			if (seen_this)
+				break;
+			col_commit = graph->commit;
+		} else {
+			col_commit = graph->columns[i].commit;
+		}
+
+		if (col_commit == graph->commit) {
+			seen_this = 1;
+			if (graph->num_parents > 1)
+				strbuf_addch(sb, 'M');
+			else
+				strbuf_addch(sb, '*');
+
+			if (graph->num_parents < 2)
+				strbuf_addch(sb, ' ');
+			else if (graph->num_parents == 2)
+				strbuf_addstr(sb, "  ");
+			else {
+				int num_dashes =
+					((graph->num_parents - 2) * 2) - 1;
+				for (j = 0; j < num_dashes; j++)
+					strbuf_addch(sb, '-');
+				strbuf_addstr(sb, ". ");
+			}
+		} else if (seen_this && (graph->num_parents > 1)) {
+			strbuf_addstr(sb, "\\ ");
+		} else {
+			strbuf_addstr(sb, "| ");
+		}
+	}
+
+	graph_pad_horizontally(graph, sb);
+
+	/*
+	 * Update graph->state
+	 */
+	if (graph->num_parents > 1)
+		graph->state = GRAPH_POST_MERGE;
+	else if (graph_is_mapping_correct(graph))
+		graph->state = GRAPH_PADDING;
+	else
+		graph->state = GRAPH_COLLAPSING;
+}
+
+void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
+{
+	int seen_this = 0;
+	int i, j;
+
+	/*
+	 * Output the post-merge row
+	 */
+	for (i = 0; i <= graph->num_columns; i++) {
+		struct commit *col_commit;
+		if (i == graph->num_columns) {
+			if (seen_this)
+				break;
+			col_commit = graph->commit;
+		} else {
+			col_commit = graph->columns[i].commit;
+		}
+
+		if (col_commit == graph->commit) {
+			seen_this = 1;
+			strbuf_addch(sb, '|');
+			for (j = 0; j < graph->num_parents - 1; j++)
+				strbuf_addstr(sb, "\\ ");
+			if (graph->num_parents == 2)
+				strbuf_addch(sb, ' ');
+		} else if (seen_this && (graph->num_parents > 2)) {
+			strbuf_addstr(sb, "\\ ");
+		} else {
+			strbuf_addstr(sb, "| ");
+		}
+	}
+
+	graph_pad_horizontally(graph, sb);
+
+	/*
+	 * Update graph->state
+	 */
+	if (graph_is_mapping_correct(graph))
+		graph->state = GRAPH_PADDING;
+	else
+		graph->state = GRAPH_COLLAPSING;
+}
+
+void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
+{
+	int i;
+	int *tmp_mapping;
+
+	/*
+	 * Clear out the new_mapping array
+	 */
+	for (i = 0; i < graph->mapping_size; i++)
+		graph->new_mapping[i] = -1;
+
+	for (i = 0; i < graph->mapping_size; i++) {
+		int target = graph->mapping[i];
+		if (target < 0)
+			continue;
+
+		/*
+		 * Since update_columns() always inserts the leftmost
+		 * column first, each branch's target location should
+		 * always be either its current location or to the left of
+		 * its current location.
+		 *
+		 * We never have to move branches to the right.  This makes
+		 * the graph much more legible, since whenever branches
+		 * cross, only one is moving directions.
+		 */
+		assert(target * 2 <= i);
+
+		if (target * 2 == i) {
+			/*
+			 * This column is already in the
+			 * correct place
+			 */
+			assert(graph->new_mapping[i] == -1);
+			graph->new_mapping[i] = target;
+		} else if (graph->new_mapping[i - 1] < 0) {
+			/*
+			 * Nothing is to the left.
+			 * Move to the left by one
+			 */
+			graph->new_mapping[i - 1] = target;
+		} else if (graph->new_mapping[i - 1] == target) {
+			/*
+			 * There is a branch line to our left
+			 * already, and it is our target.  We
+			 * combine with this line, since we share
+			 * the same parent commit.
+			 *
+			 * We don't have to add anything to the
+			 * output or new_mapping, since the
+			 * existing branch line has already taken
+			 * care of it.
+			 */
+		} else {
+			/*
+			 * There is a branch line to our left,
+			 * but it isn't our target.  We need to
+			 * cross over it.
+			 *
+			 * The space just to the left of this
+			 * branch should always be empty.
+			 */
+			assert(graph->new_mapping[i - 1] > target);
+			assert(graph->new_mapping[i - 2] < 0);
+			graph->new_mapping[i - 2] = target;
+		}
+	}
+
+	/*
+	 * The new mapping may be 1 smaller than the old mapping
+	 */
+	if (graph->new_mapping[graph->mapping_size - 1] < 0)
+		graph->mapping_size--;
+
+	/*
+	 * Output out a line based on the new mapping info
+	 */
+	for (i = 0; i < graph->mapping_size; i++) {
+		int target = graph->new_mapping[i];
+		if (target < 0)
+			strbuf_addch(sb, ' ');
+		else if (target * 2 == i)
+			strbuf_addch(sb, '|');
+		else
+			strbuf_addch(sb, '/');
+	}
+
+	graph_pad_horizontally(graph, sb);
+
+	/*
+	 * Swap mapping and new_mapping
+	 */
+	tmp_mapping = graph->mapping;
+	graph->mapping = graph->new_mapping;
+	graph->new_mapping = tmp_mapping;
+
+	/*
+	 * If graph->mapping indicates that all of the branch lines
+	 * are already in the correct positions, we are done.
+	 * Otherwise, we need to collapse some branch lines together.
+	 */
+	if (graph_is_mapping_correct(graph))
+		graph->state = GRAPH_PADDING;
+}
+
+int graph_next_line(struct git_graph *graph, struct strbuf *sb)
+{
+	switch (graph->state) {
+	case GRAPH_PADDING:
+		graph_output_padding_line(graph, sb);
+		return 0;
+	case GRAPH_SKIP:
+		graph_output_skip_line(graph, sb);
+		return 0;
+	case GRAPH_PRE_COMMIT:
+		graph_output_pre_commit_line(graph, sb);
+		return 0;
+	case GRAPH_COMMIT:
+		graph_output_commit_line(graph, sb);
+		return 1;
+	case GRAPH_POST_MERGE:
+		graph_output_post_merge_line(graph, sb);
+		return 0;
+	case GRAPH_COLLAPSING:
+		graph_output_collapsing_line(graph, sb);
+		return 0;
+	}
+
+	assert(0);
+	return 0;
+}
+
+void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
+{
+	int i, j;
+
+	if (graph->state != GRAPH_COMMIT) {
+		graph_next_line(graph, sb);
+		return;
+	}
+
+	/*
+	 * Output the row containing this commit
+	 * Iterate up to and including graph->num_columns,
+	 * since the current commit may not be in any of the existing
+	 * columns.  (This happens when the current commit doesn't have any
+	 * children that we have already processed.)
+	 */
+	for (i = 0; i < graph->num_columns; i++) {
+		struct commit *col_commit = graph->columns[i].commit;
+		if (col_commit == graph->commit) {
+			strbuf_addch(sb, '|');
+
+			if (graph->num_parents < 3)
+				strbuf_addch(sb, ' ');
+			else {
+				int num_spaces = ((graph->num_parents - 2) * 2);
+				for (j = 0; j < num_spaces; j++)
+					strbuf_addch(sb, ' ');
+			}
+		} else {
+			strbuf_addstr(sb, "| ");
+		}
+	}
+
+	graph_pad_horizontally(graph, sb);
+}
+
+int graph_is_commit_finished(struct git_graph const *graph)
+{
+	return (graph->state == GRAPH_PADDING);
+}
+
+void graph_show_commit(struct git_graph *graph)
+{
+	struct strbuf msgbuf;
+	int shown_commit_line = 0;
+
+	if (!graph)
+		return;
+
+	strbuf_init(&msgbuf, 0);
+
+	while (!shown_commit_line) {
+		shown_commit_line = graph_next_line(graph, &msgbuf);
+		fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
+		if (!shown_commit_line)
+			putchar('\n');
+		strbuf_setlen(&msgbuf, 0);
+	}
+
+	strbuf_release(&msgbuf);
+}
+
+void graph_show_oneline(struct git_graph *graph)
+{
+	struct strbuf msgbuf;
+
+	if (!graph)
+		return;
+
+	strbuf_init(&msgbuf, 0);
+	graph_next_line(graph, &msgbuf);
+	fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
+	strbuf_release(&msgbuf);
+}
+
+void graph_show_padding(struct git_graph *graph)
+{
+	struct strbuf msgbuf;
+
+	if (!graph)
+		return;
+
+	strbuf_init(&msgbuf, 0);
+	graph_padding_line(graph, &msgbuf);
+	fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
+	strbuf_release(&msgbuf);
+}
+
+int graph_show_remainder(struct git_graph *graph)
+{
+	struct strbuf msgbuf;
+	int shown = 0;
+
+	if (!graph)
+		return 0;
+
+	if (graph_is_commit_finished(graph))
+		return 0;
+
+	strbuf_init(&msgbuf, 0);
+	for (;;) {
+		graph_next_line(graph, &msgbuf);
+		fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
+		strbuf_setlen(&msgbuf, 0);
+		shown = 1;
+
+		if (!graph_is_commit_finished(graph))
+			putchar('\n');
+		else
+			break;
+	}
+	strbuf_release(&msgbuf);
+
+	return shown;
+}
+
+
+void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
+{
+	if (!graph) {
+		fwrite(sb->buf, sizeof(char), sb->len, stdout);
+		return;
+	}
+
+	/*
+	 * Print the strbuf line by line,
+	 * and display the graph info before each line but the first.
+	 */
+	char *p = sb->buf;
+	while (p) {
+		size_t len;
+		char *next_p = strchr(p, '\n');
+		if (next_p) {
+			next_p++;
+			len = next_p - p;
+		} else {
+			len = (sb->buf + sb->len) - p;
+		}
+		fwrite(p, sizeof(char), len, stdout);
+		if (next_p && *next_p != '\0')
+			graph_show_oneline(graph);
+		p = next_p;
+	}
+}
+
+void graph_show_commit_msg(struct git_graph *graph,
+			   struct strbuf const *sb)
+{
+	if (!graph) {
+		/*
+		 * If there's no graph, just print the message buffer.
+		 *
+		 * The message buffer for CMIT_FMT_ONELINE and
+		 * CMIT_FMT_USERFORMAT are already missing a terminating
+		 * newline.  All of the other formats should have it.
+		 */
+		fwrite(sb->buf, sizeof(char), sb->len, stdout);
+		return;
+	}
+
+	int newline_terminated = (sb->len && sb->buf[sb->len - 1] == '\n');
+
+	/*
+	 * Show the commit message
+	 */
+	graph_show_strbuf(graph, sb);
+
+	/*
+	 * If there is more output needed for this commit, show it now
+	 */
+	if (!graph_is_commit_finished(graph)) {
+		/*
+		 * If sb doesn't have a terminating newline, print one now,
+		 * so we can start the remainder of the graph output on a
+		 * new line.
+		 */
+		if (!newline_terminated)
+			putchar('\n');
+
+		graph_show_remainder(graph);
+
+		/*
+		 * If sb ends with a newline, our output should too.
+		 */
+		if (newline_terminated)
+			putchar('\n');
+	}
+}
diff --git a/graph.h b/graph.h
new file mode 100644
index 0000000..a7748a5
--- /dev/null
+++ b/graph.h
@@ -0,0 +1,121 @@
+#ifndef GRAPH_H
+#define GRAPH_H
+
+/* A graph is a pointer to this opaque structure */
+struct git_graph;
+
+/*
+ * Create a new struct git_graph.
+ * The graph should be freed with graph_release() when no longer needed.
+ */
+struct git_graph *graph_init();
+
+/*
+ * Destroy a struct git_graph and free associated memory.
+ */
+void graph_release(struct git_graph *graph);
+
+/*
+ * Update a git_graph with a new commit.
+ * This will cause the graph to begin outputting lines for the new commit
+ * the next time graph_next_line() is called.
+ *
+ * If graph_update() is called before graph_is_commit_finished() returns 1,
+ * the next call to graph_next_line() will output an ellipsis ("...")
+ * to indicate that a portion of the graph is missing.
+ */
+void graph_update(struct git_graph *graph, struct commit *commit);
+
+/*
+ * Output the next line for a graph.
+ * This formats the next graph line into the specified strbuf.  It is not
+ * terminated with a newline.
+ *
+ * Returns 1 if the line includes the current commit, and 0 otherwise.
+ * graph_next_line() will return 1 exactly once for each time
+ * graph_update() is called.
+ */
+int graph_next_line(struct git_graph *graph, struct strbuf *sb);
+
+/*
+ * Output a padding line in the graph.
+ * This is similar to graph_next_line().  However, it is guaranteed to
+ * never print the current commit line.  Instead, if the commit line is
+ * next, it will simply output a line of vertical padding, extending the
+ * branch lines downwards, but leaving them otherwise unchanged.
+ */
+void graph_padding_line(struct git_graph *graph, struct strbuf *sb);
+
+/*
+ * Determine if a graph has finished outputting lines for the current
+ * commit.
+ *
+ * Returns 1 if graph_next_line() needs to be called again before
+ * graph_update() should be called.  Returns 0 if no more lines are needed
+ * for this commit.  If 0 is returned, graph_next_line() may still be
+ * called without calling graph_update(), and it will merely output
+ * appropriate "vertical padding" in the graph.
+ */
+int graph_is_commit_finished(struct git_graph const *graph);
+
+
+/*
+ * graph_show_*: helper functions for printing to stdout
+ */
+
+
+/*
+ * If the graph is non-NULL, print the history graph to stdout,
+ * up to and including the line containing this commit.
+ * Does not print a terminating newline on the last line.
+ */
+void graph_show_commit(struct git_graph *graph);
+
+/*
+ * If the graph is non-NULL, print one line of the history graph to stdout.
+ * Does not print a terminating newline on the last line.
+ */
+void graph_show_oneline(struct git_graph *graph);
+
+/*
+ * If the graph is non-NULL, print one line of vertical graph padding to
+ * stdout.  Does not print a terminating newline on the last line.
+ */
+void graph_show_padding(struct git_graph *graph);
+
+/*
+ * If the graph is non-NULL, print the rest of the history graph for this
+ * commit to stdout.  Does not print a terminating newline on the last line.
+ */
+int graph_show_remainder(struct git_graph *graph);
+
+/*
+ * Print a strbuf to stdout.  If the graph is non-NULL, all lines but the
+ * first will be prefixed with the graph output.
+ *
+ * If the strbuf ends with a newline, the output will end after this
+ * newline.  A new graph line will not be printed after the final newline.
+ * If the strbuf is empty, no output will be printed.
+ *
+ * Since the first line will not include the graph ouput, the caller is
+ * responsible for printing this line's graph (perhaps via
+ * graph_show_commit() or graph_show_oneline()) before calling
+ * graph_show_strbuf().
+ */
+void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
+
+/*
+ * Print a commit message strbuf and the remainder of the graph to stdout.
+ *
+ * This is similar to graph_show_strbuf(), but it always prints the
+ * remainder of the graph.
+ *
+ * If the strbuf ends with a newline, the output printed by
+ * graph_show_commit_msg() will end with a newline.  If the strbuf is
+ * missing a terminating newline (including if it is empty), the output
+ * printed by graph_show_commit_msg() will also be missing a terminating
+ * newline.
+ */
+void graph_show_commit_msg(struct git_graph *graph, struct strbuf const *sb);
+
+#endif /* GRAPH_H */
-- 
1.5.5.1.128.gc15ea

[PATCH 3/3] log and rev-list: add --graph option

[Adam Simpkins]

This new option causes a text-based representation of the history to be
printed to the left of the normal output.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
---
 Documentation/rev-list-options.txt            |   10 +++
 Documentation/technical/api-history-graph.txt |   13 +++--
 builtin-rev-list.c                            |   50 +++++++++++++++-
 log-tree.c                                    |   76 ++++++++++++++++++++++--
 revision.c                                    |   26 ++++++++-
 revision.h                                    |    6 ++-
 6 files changed, 163 insertions(+), 18 deletions(-)

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 2648a55..ce6a101 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -75,6 +75,16 @@ you would get an output line this:
 	-xxxxxxx... 1st on a
 -----------------------------------------------------------------------
 
+--graph::
+
+	Draw a text-based graphical representation of the commit history
+	on the left hand side of the output.  This may cause extra lines
+	to be printed in between commits, in order for the graph history
+	to be drawn properly.
++
+This implies the '--topo-order' option by default, but the
+'--date-order' option may also be specified.
+
 Diff Formatting
 ~~~~~~~~~~~~~~~
 
diff --git a/Documentation/technical/api-history-graph.txt b/Documentation/technical/api-history-graph.txt
index 5f6465f..ce1c08e 100644
--- a/Documentation/technical/api-history-graph.txt
+++ b/Documentation/technical/api-history-graph.txt
@@ -74,14 +74,17 @@ state.
 Calling sequence
 ----------------
 
-* Create a `struct git_graph` by calling `graph_init()`.
+* Create a `struct git_graph` by calling `graph_init()`.  When using the
+  revision walking API, this is done automatically by `setup_revisions()` if
+  the '--graph' option is supplied.
 
 * Use the revision walking API to walk through a group of contiguous commits.
+  The `get_revision()` function automatically calls `graph_update()` each time
+  it is invoked.
 
-* For each commit traversed, call `graph_update()` to move the graph to the
-  next commit.  Once `graph_update()` has been called, call `graph_next_line()`
-  repeatedly, until `graph_is_commit_finished()` returns non-zero.  Each call
-  to `graph_next_line()` will output a single line of the graph.  The resulting
+* For each commit, call `graph_next_line()` repeatedly, until
+  `graph_is_commit_finished()` returns non-zero.  Each call go
+  `graph_next_line()` will output a single line of the graph.  The resulting
   lines will not contain any newlines.  `graph_next_line()` returns 1 if the
   resulting line contains the current commit, or 0 if this is merely a line
   needed to adjust the graph before or after the current commit.  This return
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 476a870..f868290 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -10,6 +10,7 @@
 #include "list-objects.h"
 #include "builtin.h"
 #include "log-tree.h"
+#include "graph.h"
 
 /* bits #0-15 in revision.h */
 
@@ -52,12 +53,13 @@ static struct rev_info revs;
 
 static int bisect_list;
 static int show_timestamp;
-static int hdr_termination;
 static const char *header_prefix;
 
 static void finish_commit(struct commit *commit);
 static void show_commit(struct commit *commit)
 {
+	graph_show_commit(revs.graph);
+
 	if (show_timestamp)
 		printf("%lu ", commit->date);
 	if (header_prefix)
@@ -96,9 +98,50 @@ static void show_commit(struct commit *commit)
 		pretty_print_commit(revs.commit_format, commit,
 				    &buf, revs.abbrev, NULL, NULL,
 				    revs.date_mode, 0);
-		if (buf.len)
-			printf("%s%c", buf.buf, hdr_termination);
+		if (revs.graph) {
+			if (buf.len) {
+				if (revs.commit_format != CMIT_FMT_ONELINE)
+					graph_show_oneline(revs.graph);
+
+				graph_show_commit_msg(revs.graph, &buf);
+
+				/*
+				 * Add a newline after the commit message.
+				 *
+				 * Usually, this newline produces a blank
+				 * padding line between entries, in which case
+				 * we need to add graph padding on this line.
+				 *
+				 * However, the commit message may not end in a
+				 * newline.  In this case the newline simply
+				 * ends the last line of the commit message,
+				 * and we don't need any graph output.  (This
+				 * always happens with CMIT_FMT_ONELINE, and it
+				 * happens with CMIT_FMT_USERFORMAT when the
+				 * format doesn't explicitly end in a newline.)
+				 */
+				if (buf.len && buf.buf[buf.len - 1] == '\n')
+					graph_show_padding(revs.graph);
+				putchar('\n');
+			} else {
+				/*
+				 * If the message buffer is empty, just show
+				 * the rest of the graph output for this
+				 * commit.
+				 */
+				if (graph_show_remainder(revs.graph))
+					putchar('\n');
+			}
+		} else {
+			if (buf.len) {
+				fwrite(buf.buf, sizeof(char), buf.len, stdout);
+				putchar('\n');
+			}
+		}
 		strbuf_release(&buf);
+	} else {
+		if (graph_show_remainder(revs.graph))
+			putchar('\n');
 	}
 	maybe_flush_or_die(stdout, "stdout");
 	finish_commit(commit);
@@ -592,7 +635,6 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	}
 	if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
 		/* The command line has a --pretty  */
-		hdr_termination = '\n';
 		if (revs.commit_format == CMIT_FMT_ONELINE)
 			header_prefix = "";
 		else
diff --git a/log-tree.c b/log-tree.c
index 74829d7..1474d1f 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "diff.h"
 #include "commit.h"
+#include "graph.h"
 #include "log-tree.h"
 #include "reflog-walk.h"
 
@@ -165,11 +166,16 @@ void log_write_email_headers(struct rev_info *opt, const char *name,
 	}
 
 	printf("From %s Mon Sep 17 00:00:00 2001\n", name);
-	if (opt->message_id)
+	graph_show_oneline(opt->graph);
+	if (opt->message_id) {
 		printf("Message-Id: <%s>\n", opt->message_id);
-	if (opt->ref_message_id)
+		graph_show_oneline(opt->graph);
+	}
+	if (opt->ref_message_id) {
 		printf("In-Reply-To: <%s>\nReferences: <%s>\n",
 		       opt->ref_message_id, opt->ref_message_id);
+		graph_show_oneline(opt->graph);
+	}
 	if (opt->mime_boundary) {
 		static char subject_buffer[1024];
 		static char buffer[1024];
@@ -220,6 +226,8 @@ void show_log(struct rev_info *opt)
 
 	opt->loginfo = NULL;
 	if (!opt->verbose_header) {
+		graph_show_commit(opt->graph);
+
 		if (commit->object.flags & BOUNDARY)
 			putchar('-');
 		else if (commit->object.flags & UNINTERESTING)
@@ -234,6 +242,10 @@ void show_log(struct rev_info *opt)
 		if (opt->print_parents)
 			show_parents(commit, abbrev_commit);
 		show_decorations(commit);
+		if (opt->graph && !graph_is_commit_finished(opt->graph)) {
+			putchar('\n');
+			graph_show_remainder(opt->graph);
+		}
 		putchar(opt->diffopt.line_termination);
 		return;
 	}
@@ -243,11 +255,33 @@ void show_log(struct rev_info *opt)
 	 * Otherwise, add a diffopt.line_termination character before all
 	 * entries but the first.  (IOW, as a separator between entries)
 	 */
-	if (opt->shown_one && !opt->use_terminator)
+	if (opt->shown_one && !opt->use_terminator) {
+		/*
+		 * If entries are separated by a newline, the output
+		 * should look human-readable.  If the last entry ended
+		 * with a newline, print the graph output before this
+		 * newline.  Otherwise it will end up as a completely blank
+		 * line and will look like a gap in the graph.
+		 *
+		 * If the entry separator is not a newline, the output is
+		 * primarily intended for programmatic consumption, and we
+		 * never want the extra graph output before the entry
+		 * separator.
+		 */
+		if (opt->diffopt.line_termination == '\n' &&
+		    !opt->missing_newline)
+			graph_show_padding(opt->graph);
 		putchar(opt->diffopt.line_termination);
+	}
 	opt->shown_one = 1;
 
 	/*
+	 * If the history graph was requested,
+	 * print the graph, up to this commit's line
+	 */
+	graph_show_commit(opt->graph);
+
+	/*
 	 * Print header line of header..
 	 */
 
@@ -279,8 +313,19 @@ void show_log(struct rev_info *opt)
 						  abbrev_commit));
 		show_decorations(commit);
 		printf("%s", diff_get_color_opt(&opt->diffopt, DIFF_RESET));
-		putchar(opt->commit_format == CMIT_FMT_ONELINE ? ' ' : '\n');
+		if (opt->commit_format == CMIT_FMT_ONELINE) {
+			putchar(' ');
+		} else {
+			putchar('\n');
+			graph_show_oneline(opt->graph);
+		}
 		if (opt->reflog_info) {
+			/*
+			 * setup_revisions() ensures that opt->reflog_info
+			 * and opt->graph cannot both be set,
+			 * so we don't need to worry about printing the
+			 * graph info here.
+			 */
 			show_reflog_message(opt->reflog_info,
 				    opt->commit_format == CMIT_FMT_ONELINE,
 				    opt->date_mode);
@@ -304,13 +349,30 @@ void show_log(struct rev_info *opt)
 
 	if (opt->add_signoff)
 		append_signoff(&msgbuf, opt->add_signoff);
-	if (opt->show_log_size)
+	if (opt->show_log_size) {
 		printf("log size %i\n", (int)msgbuf.len);
+		graph_show_oneline(opt->graph);
+	}
 
-	if (msgbuf.len)
+	/*
+	 * Set opt->missing_newline if msgbuf doesn't
+	 * end in a newline (including if it is empty)
+	 */
+	if (!msgbuf.len || msgbuf.buf[msgbuf.len - 1] != '\n')
+		opt->missing_newline = 1;
+	else
+		opt->missing_newline = 0;
+
+	if (opt->graph)
+		graph_show_commit_msg(opt->graph, &msgbuf);
+	else
 		fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
-	if (opt->use_terminator)
+	if (opt->use_terminator) {
+		if (!opt->missing_newline)
+			graph_show_padding(opt->graph);
 		putchar('\n');
+	}
+
 	strbuf_release(&msgbuf);
 }
 
diff --git a/revision.c b/revision.c
index a813304..c947e0f 100644
--- a/revision.c
+++ b/revision.c
@@ -6,6 +6,7 @@
 #include "diff.h"
 #include "refs.h"
 #include "revision.h"
+#include "graph.h"
 #include "grep.h"
 #include "reflog-walk.h"
 #include "patch-ids.h"
@@ -1203,6 +1204,12 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				get_commit_format(arg+8, revs);
 				continue;
 			}
+			if (!prefixcmp(arg, "--graph")) {
+				revs->topo_order = 1;
+				revs->rewrite_parents = 1;
+				revs->graph = graph_init();
+				continue;
+			}
 			if (!strcmp(arg, "--root")) {
 				revs->show_root_diff = 1;
 				continue;
@@ -1397,6 +1404,15 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 	if (revs->reverse && revs->reflog_info)
 		die("cannot combine --reverse with --walk-reflogs");
 
+	/*
+	 * Limitations on the graph functionality
+	 */
+	if (revs->reverse && revs->graph)
+		die("cannot combine --reverse with --graph");
+
+	if (revs->reflog_info && revs->graph)
+		die("cannot combine --walk-reflogs with --graph");
+
 	return left;
 }
 
@@ -1598,7 +1614,7 @@ static void gc_boundary(struct object_array *array)
 	}
 }
 
-struct commit *get_revision(struct rev_info *revs)
+static struct commit *get_revision_internal(struct rev_info *revs)
 {
 	struct commit *c = NULL;
 	struct commit_list *l;
@@ -1705,3 +1721,11 @@ struct commit *get_revision(struct rev_info *revs)
 
 	return c;
 }
+
+struct commit *get_revision(struct rev_info *revs)
+{
+	struct commit *c = get_revision_internal(revs);
+	if (c && revs->graph)
+		graph_update(revs->graph, c);
+	return c;
+}
diff --git a/revision.h b/revision.h
index 201bd97..abce500 100644
--- a/revision.h
+++ b/revision.h
@@ -66,7 +66,8 @@ struct rev_info {
 	/* Format info */
 	unsigned int	shown_one:1,
 			abbrev_commit:1,
-			use_terminator:1;
+			use_terminator:1,
+			missing_newline:1;
 	enum date_mode date_mode;
 
 	const char **ignore_packed; /* pretend objects in these are unpacked */
@@ -89,6 +90,9 @@ struct rev_info {
 	/* Filter by commit log message */
 	struct grep_opt	*grep_filter;
 
+	/* Display history graph */
+	struct git_graph *graph;
+
 	/* special limits */
 	int skip_count;
 	int max_count;
-- 
1.5.5.1.128.gc15ea

[PATCH] bash: Add more option completions for 'git log'

[Teemu Likonen]

Options added: --graph --stat --numstat --shortstat --decorate
--diff-filter= --color --no-color --color-words

Signed-off-by: Teemu Likonen <tlikonen@iki.fi>
---

I have found these bash completions useful with 'git log'. This patch
also includes the '--graph' option recently introduced by Adam Simpkins.


 contrib/completion/git-completion.bash |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 23db664..d7a8545 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -758,6 +758,10 @@ _git_log ()
 			--pretty= --name-status --name-only --raw
 			--not --all
 			--left-right --cherry-pick
+			--stat --numstat --shortstat
+			--decorate --diff-filter=
+			--color --no-color --color-words
+			--graph
 			"
 		return
 		;;
-- 
1.5.5.1.139.g8c42a

Re: [PATCH 0/3] log --graph and rev-list --graph

[Ping Yin]

On Sun, May 4, 2008 at 6:36 PM, Adam Simpkins <adam@adamsimpkins.net> wrote:
> This patch series adds a new --graph option to the log and rev-list
>  commands.  This is pretty much the same code that I sent out in early
>  April, but updated to work with the log entry termination fixes in the
>  latest master branch.
>
>  Adam Simpkins (3):
>   revision API: split parent rewriting and parent printing options
>   Add history graph API
>   log and rev-list: add --graph option
>

Is the indention between ba7f5b and 38254 intentional?

* ba7f5b log and rev-list: add --graph option
*   38254 Add history graph API
*   12918 revision API: split parent rewriting
*   c697a Cleanup xread() loops to use read_in_full()
M     47179Merge branch 'maint'

-- 
Ping Yin

Re: [PATCH 0/3] log --graph and rev-list --graph

[Adam Simpkins]

On Mon, May 05, 2008 at 10:13:43AM +0800, Ping Yin wrote:
> 
> Is the indention between ba7f5b and 38254 intentional?
> 
> * ba7f5b log and rev-list: add --graph option
> *   38254 Add history graph API
> *   12918 revision API: split parent rewriting
> *   c697a Cleanup xread() loops to use read_in_full()
> M     47179 Merge branch 'maint'


It's not really intentional, it's just the result of a rather
simplistic computation.

The amount of horizontal padding used for each commit is computed as
(2 * number of incoming columns from the previous commit) + (2 * number
of parents of the current commit).  This always results in enough
padding.  However, if the current commit is a child of one of the
incoming columns, it results in 2 more spaces than necessary.

There's a comment in graph_pad_horizontally() graph.c that describes
this behavior:

     * This computation results in 3 extra spaces to the right in most
     * cases, but only 1 extra space if the commit doesn't have any
     * children that have already been displayed in the graph (i.e.,
     * if the current commit isn't in graph->columns).

It could easily be fixed by performing an extra pass over the columns
to check if any of the existing columns refers to the current commit.

I'll try to come up with a patch when I get the chance.

-- 
Adam Simpkins
adam@adamsimpkins.net

[PATCH] graph API: eliminate unnecessary indentation

[Adam Simpkins]

This change improves the calculation of the amount of horizontal
padding, so that there is always exactly 1 space of padding.
Previously, most commits had 3 spaces of padding, but commits that
didn't have any children in the graph had only 1 space of padding.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
---

This fixes the issue reported by Ping Yin.

 graph.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 52 insertions(+), 14 deletions(-)

diff --git a/graph.c b/graph.c
index b575d10..809a582 100644
--- a/graph.c
+++ b/graph.c
@@ -61,6 +61,12 @@ struct git_graph {
 	 */
 	int num_parents;
 	/*
+	 * The width of the graph output for this commit.
+	 * All rows for this commit are padded to this width, so that
+	 * messages printed after the graph output are aligned.
+	 */
+	int width;
+	/*
 	 * The next expansion row to print
 	 * when state is GRAPH_PRE_COMMIT
 	 */
@@ -207,13 +213,48 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
 	graph->num_new_columns++;
 }
 
+static void graph_update_width(struct git_graph *graph,
+			       int is_commit_in_existing_columns)
+{
+	/*
+	 * Compute the width needed to display the graph for this commit.
+	 * This is the maximum width needed for any row.  All other rows
+	 * will be padded to this width.
+	 *
+	 * Compute the number of columns in the widest row:
+	 * Count each existing column (graph->num_columns), and each new
+	 * column added by this commit.
+	 */
+	int max_cols = graph->num_columns + graph->num_parents;
+
+	/*
+	 * Even if the current commit has no parents, it still takes up a
+	 * column for itself.
+	 */
+	if (graph->num_parents < 1)
+		max_cols++;
+
+	/*
+	 * We added a column for the the current commit as part of
+	 * graph->num_parents.  If the current commit was already in
+	 * graph->columns, then we have double counted it.
+	 */
+	if (is_commit_in_existing_columns)
+		max_cols--;
+
+	/*
+	 * Each column takes up 2 spaces
+	 */
+	graph->width = max_cols * 2;
+}
+
 static void graph_update_columns(struct git_graph *graph)
 {
 	struct commit_list *parent;
 	struct column *tmp_columns;
 	int max_new_columns;
 	int mapping_idx;
-	int i, seen_this;
+	int i, seen_this, is_commit_in_columns;
 
 	/*
 	 * Swap graph->columns with graph->new_columns
@@ -259,11 +300,13 @@ static void graph_update_columns(struct git_graph *graph)
 	 */
 	seen_this = 0;
 	mapping_idx = 0;
+	is_commit_in_columns = 1;
 	for (i = 0; i <= graph->num_columns; i++) {
 		struct commit *col_commit;
 		if (i == graph->num_columns) {
 			if (seen_this)
 				break;
+			is_commit_in_columns = 0;
 			col_commit = graph->commit;
 		} else {
 			col_commit = graph->columns[i].commit;
@@ -290,6 +333,11 @@ static void graph_update_columns(struct git_graph *graph)
 	while (graph->mapping_size > 1 &&
 	       graph->mapping[graph->mapping_size - 1] < 0)
 		graph->mapping_size--;
+
+	/*
+	 * Compute graph->width for this commit
+	 */
+	graph_update_width(graph, is_commit_in_columns);
 }
 
 void graph_update(struct git_graph *graph, struct commit *commit)
@@ -368,22 +416,12 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
 	 *
 	 * This way, fields printed to the right of the graph will remain
 	 * aligned for the entire commit.
-	 *
-	 * This computation results in 3 extra space to the right in most
-	 * cases, but only 1 extra space if the commit doesn't have any
-	 * children that have already been displayed in the graph (i.e.,
-	 * if the current commit isn't in graph->columns).
 	 */
-	size_t extra;
-	size_t final_width = graph->num_columns + graph->num_parents;
-	if (graph->num_parents < 1)
-		final_width++;
-	final_width *= 2;
-
-	if (sb->len >= final_width)
+	int extra;
+	if (sb->len >= graph->width)
 		return;
 
-	extra = final_width - sb->len;
+	extra = graph->width - sb->len;
 	strbuf_addf(sb, "%*s", extra, "");
 }
 
-- 
1.5.3.6

Re: [PATCH] graph API: eliminate unnecessary indentation

[Ping Yin]

On Mon, May 5, 2008 at 3:57 PM, Adam Simpkins <adam@adamsimpkins.net> wrote:
> This change improves the calculation of the amount of horizontal
>  padding, so that there is always exactly 1 space of padding.
>  Previously, most commits had 3 spaces of padding, but commits that
>  didn't have any children in the graph had only 1 space of padding.
>
>  Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
>  ---
>
>  This fixes the issue reported by Ping Yin.
>

Yes, this patch has fix that problem. THX.

-- 
Ping Yin

Re: [PATCH 2/3] Add history graph API

[Junio C Hamano]

Adam Simpkins <adam@adamsimpkins.net> writes:

> +* The graph API does not currently support reverse commit ordering.  In
> +  order to implement reverse ordering, the graphing API needs an
> +  (efficient) mechanism to find the children of a commit.

You might want to take a look at the 'jc/blame' topic that have been
brewing in 'next' for the three weeks, most notably f35f560 (revision
traversal: --children option, 2008-04-03).

This series needs tests.

Re: [PATCH 3/3] log and rev-list: add --graph option

[Junio C Hamano]

Adam Simpkins <adam@adamsimpkins.net> writes:

> diff --git a/builtin-rev-list.c b/builtin-rev-list.c
> index 476a870..f868290 100644
> --- a/builtin-rev-list.c
> +++ b/builtin-rev-list.c
> ...
> @@ -52,12 +53,13 @@ static struct rev_info revs;
>  
>  static int bisect_list;
>  static int show_timestamp;
> -static int hdr_termination;
>  static const char *header_prefix;
>  
>  static void finish_commit(struct commit *commit);
>  static void show_commit(struct commit *commit)
>  {
> +	graph_show_commit(revs.graph);
> +
>  	if (show_timestamp)
>  		printf("%lu ", commit->date);
>  	if (header_prefix)
> @@ -96,9 +98,50 @@ static void show_commit(struct commit *commit)
>  		pretty_print_commit(revs.commit_format, commit,
>  				    &buf, revs.abbrev, NULL, NULL,
>  				    revs.date_mode, 0);
> -		if (buf.len)
> -			printf("%s%c", buf.buf, hdr_termination);
> +		if (revs.graph) {
> ...
> +		} else {
> +			if (buf.len) {
> +				fwrite(buf.buf, sizeof(char), buf.len, stdout);
> +				putchar('\n');

Now hdr_termination can never be NUL, iow you broke "rev-list -v -z"?

I'll squash in a minimum fix, because otherwise this breaks existing
tests.

--

 builtin-rev-list.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index f868290..54d55cc 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -53,6 +53,7 @@ static struct rev_info revs;
 
 static int bisect_list;
 static int show_timestamp;
+static int hdr_termination;
 static const char *header_prefix;
 
 static void finish_commit(struct commit *commit);
@@ -133,10 +134,8 @@ static void show_commit(struct commit *commit)
 					putchar('\n');
 			}
 		} else {
-			if (buf.len) {
-				fwrite(buf.buf, sizeof(char), buf.len, stdout);
-				putchar('\n');
-			}
+			if (buf.len)
+				printf("%s%c", buf.buf, hdr_termination);
 		}
 		strbuf_release(&buf);
 	} else {
@@ -635,6 +634,7 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 	}
 	if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
 		/* The command line has a --pretty  */
+		hdr_termination = '\n';
 		if (revs.commit_format == CMIT_FMT_ONELINE)
 			header_prefix = "";
 		else

Re: [PATCH 3/3] log and rev-list: add --graph option

[Adam Simpkins]

On Mon, May 05, 2008 at 11:41:58PM -0700, Junio C Hamano wrote:
> Adam Simpkins <adam@adamsimpkins.net> writes:
> 
> > diff --git a/builtin-rev-list.c b/builtin-rev-list.c
> > index 476a870..f868290 100644
> > --- a/builtin-rev-list.c
> > +++ b/builtin-rev-list.c
> > ...
> > @@ -96,9 +98,50 @@ static void show_commit(struct commit *commit)
> >  		pretty_print_commit(revs.commit_format, commit,
> >  				    &buf, revs.abbrev, NULL, NULL,
> >  				    revs.date_mode, 0);
> > -		if (buf.len)
> > -			printf("%s%c", buf.buf, hdr_termination);
> > +		if (revs.graph) {
> > ...
> > +		} else {
> > +			if (buf.len) {
> > +				fwrite(buf.buf, sizeof(char), buf.len, stdout);
> > +				putchar('\n');
> 
> Now hdr_termination can never be NUL, iow you broke "rev-list -v -z"?

Whoops.  Sorry about that.  I didn't notice the "-v" option.

(BTW, I don't think the "-z" option comes into play here.  Just
"rev-list -v" by itself results in a NUL character after each entry
instead of a newline.)

> I'll squash in a minimum fix, because otherwise this breaks existing
> tests.

Thanks!

-- 
Adam Simpkins
adam@adamsimpkins.net

Re: [PATCH 0/3] log --graph and rev-list --graph

[Teemu Likonen]

Adam Simpkins wrote (2008-05-04 03:36 -0700):

> This patch series adds a new --graph option to the log and rev-list
> commands.  This is pretty much the same code that I sent out in early
> April, but updated to work with the log entry termination fixes in the
> latest master branch.

Looks great, with the exception of the defects we already know: (1)
diff(stat) options write their output to the graph area and (2) --follow
shows really weird lines (gitk has the same "feature").

Other than that it seems really solid. Don't know about the code but
from user's point of view:

Tested-by: Teemu Likonen <tlikonen@iki.fi>