[PATCH v6 03/12] Add git-column and column mode parsing

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

A column option string consists of many token separated by either
space of commas. A token belongs to one of three groups:

 - enabling: always, never and auto
 - layout mode: to be implemented
 - other tuning, which could be negated be prefix 'no'

A command line option without argument (e.g. --column) will enable
column output and reuse existing settings (layout mode and options..).
--no-column disables columnar output.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Turn colopts to unsigned int from the beginning.

 .gitignore                   |    1 +
 Documentation/git-column.txt |   49 ++++++++++++++++
 Makefile                     |    1 +
 builtin.h                    |    1 +
 builtin/column.c             |   41 ++++++++++++++
 column.c                     |  125 ++++++++++++++++++++++++++++++++++++++++++
 column.h                     |    7 ++
 command-list.txt             |    1 +
 git.c                        |    1 +
 parse-options.h              |    2 +
 t/t9002-column.sh            |   27 +++++++++
 11 files changed, 256 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-column.txt
 create mode 100644 builtin/column.c
 create mode 100755 t/t9002-column.sh

diff --git a/.gitignore b/.gitignore
index 3b7680e..039e5ef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,6 +26,7 @@
 /git-cherry-pick
 /git-clean
 /git-clone
+/git-column
 /git-commit
 /git-commit-tree
 /git-config
diff --git a/Documentation/git-column.txt b/Documentation/git-column.txt
new file mode 100644
index 0000000..508b85f
--- /dev/null
+++ b/Documentation/git-column.txt
@@ -0,0 +1,49 @@
+git-column(1)
+=============
+
+NAME
+----
+git-column - Display data in columns
+
+SYNOPSIS
+--------
+[verse]
+'git column' [--mode=<mode> | --rawmode=<n>] [--width=<width>]
+	     [--indent=<string>] [--nl=<string>] [--pading=<n>]
+
+DESCRIPTION
+-----------
+This command formats its input into multiple columns.
+
+OPTIONS
+-------
+--mode=<mode>::
+	Specify layout mode. See configuration variable column.ui for option
+	syntax.
+
+--rawmode=<n>::
+	Same as --mode but take mode encoded as a number. This is mainly used
+	by other commands that have already parsed layout mode.
+
+--width=<width>::
+	Specify the terminal width. By default 'git column' will detect the
+	terminal width, or fall back to 80 if it is unable to do so.
+
+--indent=<string>::
+	String to be printed at the beginning of each line.
+
+--nl=<N>::
+	String to be printed at the end of each line,
+	including newline character.
+
+--padding=<N>::
+	The number of spaces between columns. One space by default.
+
+
+Author
+------
+Written by Nguyen Thai Ngoc Duy <pclouds@gmail.com>
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Makefile b/Makefile
index 5f0531b..92700ca 100644
--- a/Makefile
+++ b/Makefile
@@ -766,6 +766,7 @@ BUILTIN_OBJS += builtin/checkout-index.o
 BUILTIN_OBJS += builtin/checkout.o
 BUILTIN_OBJS += builtin/clean.o
 BUILTIN_OBJS += builtin/clone.o
+BUILTIN_OBJS += builtin/column.o
 BUILTIN_OBJS += builtin/commit-tree.o
 BUILTIN_OBJS += builtin/commit.o
 BUILTIN_OBJS += builtin/config.o
diff --git a/builtin.h b/builtin.h
index 857b9c8..338f540 100644
--- a/builtin.h
+++ b/builtin.h
@@ -61,6 +61,7 @@ extern int cmd_cherry(int argc, const char **argv, const char *prefix);
 extern int cmd_cherry_pick(int argc, const char **argv, const char *prefix);
 extern int cmd_clone(int argc, const char **argv, const char *prefix);
 extern int cmd_clean(int argc, const char **argv, const char *prefix);
+extern int cmd_column(int argc, const char **argv, const char *prefix);
 extern int cmd_commit(int argc, const char **argv, const char *prefix);
 extern int cmd_commit_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_config(int argc, const char **argv, const char *prefix);
diff --git a/builtin/column.c b/builtin/column.c
new file mode 100644
index 0000000..3b0f74e
--- /dev/null
+++ b/builtin/column.c
@@ -0,0 +1,41 @@
+#include "builtin.h"
+#include "cache.h"
+#include "strbuf.h"
+#include "parse-options.h"
+#include "string-list.h"
+#include "column.h"
+
+static const char * const builtin_column_usage[] = {
+	"git column [options]",
+	NULL
+};
+static unsigned int colopts;
+
+int cmd_column(int argc, const char **argv, const char *prefix)
+{
+	struct string_list list = STRING_LIST_INIT_DUP;
+	struct strbuf sb = STRBUF_INIT;
+	struct column_options copts;
+	struct option options[] = {
+		OPT_COLUMN(0, "mode", &colopts, "layout to use"),
+		OPT_INTEGER(0, "rawmode", &colopts, "layout to use"),
+		OPT_INTEGER(0, "width", &copts.width, "Maximum width"),
+		OPT_STRING(0, "indent", &copts.indent, "string", "Padding space on left border"),
+		OPT_INTEGER(0, "nl", &copts.nl, "Padding space on right border"),
+		OPT_INTEGER(0, "padding", &copts.padding, "Padding space between columns"),
+		OPT_END()
+	};
+
+	memset(&copts, 0, sizeof(copts));
+	copts.width = term_columns();
+	copts.padding = 1;
+	argc = parse_options(argc, argv, "", options, builtin_column_usage, 0);
+	if (argc)
+		usage_with_options(builtin_column_usage, options);
+
+	while (!strbuf_getline(&sb, stdin, '\n'))
+		string_list_append(&list, sb.buf);
+
+	print_columns(&list, colopts, &copts);
+	return 0;
+}
diff --git a/column.c b/column.c
index 742ae18..d20cf8f 100644
--- a/column.c
+++ b/column.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "column.h"
 #include "string-list.h"
+#include "parse-options.h"
 
 #define MODE(mode) ((mode) & COL_MODE)
 
@@ -37,3 +38,127 @@ void print_columns(const struct string_list *list, unsigned int mode,
 	}
 	die("BUG: invalid mode %d", MODE(mode));
 }
+
+struct colopt {
+	enum {
+		ENABLE,
+		MODE,
+		OPTION
+	} type;
+	const char *name;
+	int value;
+};
+
+/*
+ * Set COL_ENABLED and COL_ENABLED_SET. If 'set' is -1, check if
+ * stdout is tty.
+ */
+static int set_enable_bit(unsigned int *mode, int set, int stdout_is_tty)
+{
+	if (set < 0) {	/* auto */
+		if (stdout_is_tty < 0)
+			stdout_is_tty = isatty(1);
+		set = stdout_is_tty || (pager_in_use() && pager_use_color);
+	}
+	if (set)
+		*mode = *mode | COL_ENABLED | COL_ENABLED_SET;
+	else
+		*mode = (*mode & ~COL_ENABLED) | COL_ENABLED_SET;
+	return 0;
+}
+
+/*
+ * Set COL_MODE_*. mode is intially copied from column.ui. If
+ * COL_ENABLED_SET is not set, then neither 'always', 'never' nor
+ * 'auto' has been used. Default to 'always'.
+ */
+static int set_mode(unsigned int *mode, unsigned int value)
+{
+	*mode = (*mode & ~COL_MODE) | value;
+	if (!(*mode & COL_ENABLED_SET))
+		*mode |= COL_ENABLED | COL_ENABLED_SET;
+
+	return 0;
+}
+
+/* Set or unset other COL_* */
+static int set_option(unsigned int *mode, unsigned int opt, int set)
+{
+	if (set)
+		*mode |= opt;
+	else
+		*mode &= ~opt;
+	return 0;
+}
+
+static int parse_option(const char *arg, int len,
+			unsigned int *mode, int stdout_is_tty)
+{
+	struct colopt opts[] = {
+		{ ENABLE, "always",  1 },
+		{ ENABLE, "never",   0 },
+		{ ENABLE, "auto",   -1 },
+	};
+	int i, set, name_len;
+
+	for (i = 0; i < ARRAY_SIZE(opts); i++) {
+		if (opts[i].type == OPTION) {
+			if (len > 2 && !strncmp(arg, "no", 2)) {
+				arg += 2;
+				len -= 2;
+				set = 0;
+			}
+			else
+				set = 1;
+		}
+
+		name_len = strlen(opts[i].name);
+		if (len != name_len ||
+		    strncmp(arg, opts[i].name, name_len))
+			continue;
+
+		switch (opts[i].type) {
+		case ENABLE: return set_enable_bit(mode, opts[i].value,
+						   stdout_is_tty);
+		case MODE: return set_mode(mode, opts[i].value);
+		case OPTION: return set_option(mode, opts[i].value, set);
+		default: die("BUG: Unknown option type %d", opts[i].type);
+		}
+	}
+
+	return error("unsupported style '%s'", arg);
+}
+
+int git_config_column(unsigned int *mode, const char *value,
+		      int stdout_is_tty)
+{
+	const char *sep = " ,";
+
+	while (*value) {
+		int len = strcspn(value, sep);
+		if (len) {
+			if (parse_option(value, len, mode, stdout_is_tty))
+				return -1;
+
+			value += len;
+		}
+		value += strspn(value, sep);
+	}
+	return 0;
+}
+
+int parseopt_column_callback(const struct option *opt,
+			     const char *arg, int unset)
+{
+	unsigned int *mode = opt->value;
+	if (unset) {
+		*mode = (*mode & ~COL_ENABLED) | COL_ENABLED_SET;
+		return 0;
+	}
+	if (arg)
+		return git_config_column(mode, arg, -1);
+
+	/* no arg, turn it on */
+	*mode |= COL_ENABLED | COL_ENABLED_SET;
+	return 0;
+}
diff --git a/column.h b/column.h
index 8e4fdaa..f48fa81 100644
--- a/column.h
+++ b/column.h
@@ -3,6 +3,7 @@
 
 #define COL_MODE          0x000F
 #define COL_ENABLED      (1 << 4)
+#define COL_ENABLED_SET  (1 << 5)  /* Has COL_ENABLED been set by config? */
 
 struct column_options {
 	int width;
@@ -15,5 +16,11 @@ extern int term_columns(void);
 extern void print_columns(const struct string_list *list,
 			  unsigned int mode,
 			  struct column_options *opts);
+extern int git_config_column(unsigned int *mode, const char *value,
+			     int stdout_is_tty);
+
+struct option;
+extern int parseopt_column_callback(const struct option *opt,
+				    const char *arg, int unset);
 
 #endif
diff --git a/command-list.txt b/command-list.txt
index a36ee9b..fe06f15 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -20,6 +20,7 @@ git-cherry-pick                         mainporcelain
 git-citool                              mainporcelain
 git-clean                               mainporcelain
 git-clone                               mainporcelain common
+git-column                              purehelpers
 git-commit                              mainporcelain common
 git-commit-tree                         plumbingmanipulators
 git-config                              ancillarymanipulators
diff --git a/git.c b/git.c
index 3805616..419e3cc 100644
--- a/git.c
+++ b/git.c
@@ -348,6 +348,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 		{ "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 		{ "clone", cmd_clone },
+		{ "column", cmd_column },
 		{ "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 		{ "commit-tree", cmd_commit_tree, RUN_SETUP },
 		{ "config", cmd_config, RUN_SETUP_GENTLY },
diff --git a/parse-options.h b/parse-options.h
index 2e811dc..56fcafd 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -238,5 +238,7 @@ extern int parse_opt_noop_cb(const struct option *, const char *, int);
 	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
 #define OPT__COLOR(var, h) \
 	OPT_COLOR_FLAG(0, "color", (var), (h))
+#define OPT_COLUMN(s, l, v, h) \
+	{ OPTION_CALLBACK, (s), (l), (v), "style", (h), PARSE_OPT_OPTARG, parseopt_column_callback }
 
 #endif
diff --git a/t/t9002-column.sh b/t/t9002-column.sh
new file mode 100755
index 0000000..b0b6d62
--- /dev/null
+++ b/t/t9002-column.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+test_description='git column'
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	cat >lista <<\EOF
+one
+two
+three
+four
+five
+six
+seven
+eight
+nine
+ten
+eleven
+EOF
+'
+
+test_expect_success 'never' '
+	git column --mode=never <lista >actual &&
+	test_cmp lista actual
+'
+
+test_done
-- 
1.7.8.36.g69ee2