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vcs-svn: implement text-delta handling

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Handle input in Subversion's dumpfile format, version 3.  This is the
format produced by "svnrdump dump" and "svnadmin dump --deltas", and
the main difference between v3 dumpfiles and the dumpfiles already
handled is that these can include nodes whose properties and text are
expressed relative to some other node.

To handle such nodes, we find which node the text and properties are
based on, handle its property changes, use the cat-blob command to
request the basis blob from the fast-import backend, use the
svndiff0_apply() helper to apply the text delta on the fly, writing
output to a temporary file, and then measure that postimage file's
length and write its content to the fast-import stream.

The temporary postimage file is shared between delta-using nodes to
avoid some file system overhead.

The svn-fe interface needs to be more complicated to accomodate the
backward flow of information from the fast-import backend to svn-fe.
The backflow fd is not needed when parsing streams without deltas,
though, so existing scripts using svn-fe on v2 dumps should
continue to work.

NEEDSWORK: generalize interface so caller sets the backflow fd, close
temporary file before exiting

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
This commit is contained in:
David Barr
2011-03-19 18:20:54 +11:00
committed by Jonathan Nieder
parent e9f3f8b6f4
commit 7a75e661c5
5 changed files with 227 additions and 11 deletions
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13
vcs-svn/svndump.c
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@ -217,9 +217,7 @@ static void handle_node(void)
*/
static const char *const empty_blob = "::empty::";
const char *old_data = NULL;
if (node_ctx.text_delta)
die("text deltas not supported");
uint32_t old_mode = REPO_MODE_BLB;
if (node_ctx.action == NODEACT_DELETE) {
if (have_text || have_props || node_ctx.srcRev)
@ -255,6 +253,7 @@ static void handle_node(void)
if (mode != REPO_MODE_DIR && type == REPO_MODE_DIR)
die("invalid dump: cannot modify a file into a directory");
node_ctx.type = mode;
old_mode = mode;
} else if (node_ctx.action == NODEACT_ADD) {
if (type == REPO_MODE_DIR)
old_data = NULL;
@ -289,8 +288,14 @@ static void handle_node(void)
fast_export_modify(node_ctx.dst.buf, node_ctx.type, old_data);
return;
}
if (!node_ctx.text_delta) {
fast_export_modify(node_ctx.dst.buf, node_ctx.type, "inline");
fast_export_data(node_ctx.type, node_ctx.textLength, &input);
return;
}
fast_export_modify(node_ctx.dst.buf, node_ctx.type, "inline");
fast_export_data(node_ctx.type, node_ctx.textLength, &input);
fast_export_blob_delta(node_ctx.type, old_mode, old_data,
node_ctx.textLength, &input);
}
static void begin_revision(void)