[PATCH v2] vcs-svn: prepare to eliminate repo_tree structure

[Jonathan Nieder <jrnieder@gmail.com>]

Date: Fri, 10 Dec 2010 04:28:06 -0600

Currently svn-fe processes each commit in two stages: first decide on
the correct content for all paths and export the relevant blobs, then
export a commit with the result.

But we can keep less state and simplify svn-fe a great deal by doing
exporting the commit in one stage: use 'inline' blobs for each path
and remember nothing.  This way, the repo_tree structure could be
eliminated, and we would get support for incremental imports 'for
free'.

Reorganize handle_node() along these lines.  This is just a code
cleanup; the functional change to repo_tree will come later.

Backported by David Barr to apply without text delta support.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Hi,

Jonathan Nieder wrote:

[...]
> @@ -228,7 +234,9 @@ static void handle_node(void)
>  	} else if (node_ctx.action == NODEACT_CHANGE) {
>  		uint32_t mode;
>  		old_mark = repo_read_path(node_ctx.dst);
> -		mode = repo_modify_path(node_ctx.dst, 0, mark);
> +		if (!have_text)
> +			mark = old_mark;
> +		mode = repo_modify_path(node_ctx.dst, 0, 0);
[...]

Backported so we can merge it a little sooner (thanks!).  It's very
similar to the original patch except there is no old_mark --- the
previous text at a path is useless until we learn to patch it (which
is a topic for another day).

David, may I have your sign-off on this series (the
vcs-svn-incremental branch)?

 vcs-svn/svndump.c |   33 +++++++++++++++++++++++----------
 1 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/vcs-svn/svndump.c b/vcs-svn/svndump.c
index ee7c0bb..f07376f 100644
--- a/vcs-svn/svndump.c
+++ b/vcs-svn/svndump.c
@@ -201,13 +201,14 @@ static void handle_node(void)
 	uint32_t mark = 0;
 	const uint32_t type = node_ctx.type;
 	const int have_props = node_ctx.propLength != LENGTH_UNKNOWN;
+	const int have_text = node_ctx.textLength != LENGTH_UNKNOWN;
 
 	if (node_ctx.text_delta)
 		die("text deltas not supported");
-	if (node_ctx.textLength != LENGTH_UNKNOWN)
+	if (have_text)
 		mark = next_blob_mark();
 	if (node_ctx.action == NODEACT_DELETE) {
-		if (mark || have_props || node_ctx.srcRev)
+		if (have_text || have_props || node_ctx.srcRev)
 			die("invalid dump: deletion node has "
 				"copyfrom info, text, or properties");
 		return repo_delete(node_ctx.dst);
@@ -221,13 +222,20 @@ static void handle_node(void)
 		if (node_ctx.action == NODEACT_ADD)
 			node_ctx.action = NODEACT_CHANGE;
 	}
-	if (mark && type == REPO_MODE_DIR)
+	if (have_text && type == REPO_MODE_DIR)
 		die("invalid dump: directories cannot have text attached");
+
+	/*
+	 * Decide on the new content (mark) and mode (node_ctx.type).
+	 */
 	if (node_ctx.action == NODEACT_CHANGE && !~*node_ctx.dst) {
 		if (type != REPO_MODE_DIR)
 			die("invalid dump: root of tree is not a regular file");
 	} else if (node_ctx.action == NODEACT_CHANGE) {
-		uint32_t mode = repo_modify_path(node_ctx.dst, 0, mark);
+		uint32_t mode;
+		if (!have_text)
+			mark = repo_read_path(node_ctx.dst);
+		mode = repo_modify_path(node_ctx.dst, 0, 0);
 		if (!mode)
 			die("invalid dump: path to be modified is missing");
 		if (mode == REPO_MODE_DIR && type != REPO_MODE_DIR)
@@ -236,22 +244,27 @@ static void handle_node(void)
 			die("invalid dump: cannot modify a file into a directory");
 		node_ctx.type = mode;
 	} else if (node_ctx.action == NODEACT_ADD) {
-		if (!mark && type != REPO_MODE_DIR)
+		if (!have_text && type != REPO_MODE_DIR)
 			die("invalid dump: adds node without text");
-		repo_add(node_ctx.dst, type, mark);
 	} else {
 		die("invalid dump: Node-path block lacks Node-action");
 	}
+
+	/*
+	 * Adjust mode to reflect properties.
+	 */
 	if (have_props) {
-		const uint32_t old_mode = node_ctx.type;
 		if (!node_ctx.prop_delta)
 			node_ctx.type = type;
 		if (node_ctx.propLength)
 			read_props();
-		if (node_ctx.type != old_mode)
-			repo_modify_path(node_ctx.dst, node_ctx.type, mark);
 	}
-	if (mark)
+
+	/*
+	 * Save the result.
+	 */
+	repo_add(node_ctx.dst, node_ctx.type, mark);
+	if (have_text)
 		fast_export_blob(node_ctx.type, mark,
 				 node_ctx.textLength, &input);
 }
-- 
1.7.4.1.91.g15e19.dirty