vcs-svn: introduce repo_read_path to check the content at a path

The repo_tree structure remembers, for each path in each revision, a
mode (regular file, executable, symlink, or directory) and content
(blob mark or directory structure).  Maintaining a second copy of all
this information when it's already in the target repository is
wasteful, it does not persist between svn-fe invocations, and most
importantly, there is no convenient way to transfer it from one
machine to another.  So it would be nice to get rid of it.

As a first step, let's change the repo_tree API to match fast-import's
read commands more closely.  Currently to read the mode for a path,
one uses

	repo_modify_path(path, new_mode, new_content);

which changes the mode and content as a side effect.  There is no
function to read the content at a path; add one.

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>

vcs-svn/repo_tree.c

@@ -87,7 +87,8 @@ static struct repo_dir *repo_clone_dir(struct repo_dir *orig_dir)
 	return dir_pointer(new_o);
 }
 
-static struct repo_dirent *repo_read_dirent(uint32_t revision, uint32_t *path)
+static struct repo_dirent *repo_read_dirent(uint32_t revision,
+					    const uint32_t *path)
 {
 	uint32_t name = 0;
 	struct repo_dirent *key = dent_pointer(dent_alloc(1));
@@ -157,6 +158,15 @@ static void repo_write_dirent(uint32_t *path, uint32_t mode,
 		dent_remove(&dir_pointer(parent_dir_o)->entries, dent);
 }
 
+uint32_t repo_read_path(const uint32_t *path)
+{
+	uint32_t content_offset = 0;
+	struct repo_dirent *dent = repo_read_dirent(active_commit, path);
+	if (dent != NULL)
+		content_offset = dent->content_offset;
+	return content_offset;
+}
+
 uint32_t repo_copy(uint32_t revision, uint32_t *src, uint32_t *dst)
 {
 	uint32_t mode = 0, content_offset = 0;

vcs-svn/repo_tree.h

@@ -15,6 +15,7 @@ uint32_t next_blob_mark(void);
 uint32_t repo_copy(uint32_t revision, uint32_t *src, uint32_t *dst);
 void repo_add(uint32_t *path, uint32_t mode, uint32_t blob_mark);
 uint32_t repo_modify_path(uint32_t *path, uint32_t mode, uint32_t blob_mark);
+uint32_t repo_read_path(const uint32_t *path);
 void repo_delete(uint32_t *path);
 void repo_commit(uint32_t revision, uint32_t author, char *log, uint32_t uuid,
 		 uint32_t url, long unsigned timestamp);