[PATCH v3 05/10] vcs-svn: move commit parameters logic to svndump.c

[Dmitry Ivankov <divanorama@gmail.com>]

fast_export.c had logic to set up commit ref, author name, email,
parent commit, import mark and git-svn-id: line based on both it's
own state (current import batch history) and the arguments passed.

Do separate the layers: make fast_export focus on producing the
fast-import stream, applying the deltas but not on svn-fe specific
logic. svndump now is responsible for choosing commit parents, marks,
ref name. Making it possible to generate incremental streams, produce
stream for several branches at a time, customize progress lines generation
and adding new logic becomes easier.

fast_export API changes:
- make fast_export_begin_commit to be more intuitive by using a set of
  parameters closer to what gets written to fast-import.

- rename fast_export_end_commit to fast_export_progress as it does only
  a progress line generation. fast_export_end_commit can be reintroduced
  once the need will arise.

- git-svn-id line is now a caller concern. If it is needed, it should be
  simply appended to the log message.

- author_name and author_email are now generated by the caller.

- ref name to be updated with the commit is now a parameter rather than
  a fixed "refs/heads/master".

The caller now may have to setup temporary buffers for author identity,
ref names, etc. This is a small additional per-commit cost to arrange
and/or copy them. Though, it's only per-commit rather that per-path
and might be worth the gain in readablity.

Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 vcs-svn/fast_export.c |   47 +++++++++++++----------------------------------
 vcs-svn/fast_export.h |    8 ++++----
 vcs-svn/svndump.c     |   44 +++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 56 insertions(+), 43 deletions(-)

diff --git a/vcs-svn/fast_export.c b/vcs-svn/fast_export.c
index 19d7c34..3dfccd2 100644
--- a/vcs-svn/fast_export.c
+++ b/vcs-svn/fast_export.c
@@ -13,9 +13,6 @@
 #include "sliding_window.h"
 #include "line_buffer.h"
 
-#define MAX_GITSVN_LINE_LEN 4096
-
-static uint32_t first_commit_done;
 static struct line_buffer postimage = LINE_BUFFER_INIT;
 static struct line_buffer report_buffer = LINE_BUFFER_INIT;
 
@@ -31,7 +28,6 @@ static int init_postimage(void)
 
 void fast_export_init(int fd)
 {
-	first_commit_done = 0;
 	if (buffer_fdinit(&report_buffer, fd))
 		die_errno("cannot read from file descriptor %d", fd);
 }
@@ -73,40 +69,23 @@ void fast_export_modify(const char *path, uint32_t mode, const char *dataref)
 	putchar('\n');
 }
 
-static char gitsvnline[MAX_GITSVN_LINE_LEN];
-void fast_export_begin_commit(uint32_t revision, const char *author,
-			const struct strbuf *log,
-			const char *uuid, const char *url,
-			unsigned long timestamp)
+void fast_export_begin_commit(const char *ref, uint32_t mark, const char *from,
+			const char *author_name, const char *author_email,
+			const struct strbuf *log, unsigned long timestamp)
 {
-	static const struct strbuf empty = STRBUF_INIT;
-	if (!log)
-		log = &empty;
-	if (*uuid && *url) {
-		snprintf(gitsvnline, MAX_GITSVN_LINE_LEN,
-				"\n\ngit-svn-id: %s@%"PRIu32" %s\n",
-				 url, revision, uuid);
-	} else {
-		*gitsvnline = '\0';
-	}
-	printf("commit refs/heads/master\n");
-	printf("mark :%"PRIu32"\n", revision);
-	printf("committer %s <%s@%s> %ld +0000\n",
-		   *author ? author : "nobody",
-		   *author ? author : "nobody",
-		   *uuid ? uuid : "local", timestamp);
-	printf("data %"PRIuMAX"\n",
-		(uintmax_t) (log->len + strlen(gitsvnline)));
+	printf("commit %s\n", ref);
+	if (mark)
+		printf("mark :%"PRIu32"\n", mark);
+	printf("committer %s <%s> %ld +0000\n",
+		author_name, author_email, timestamp);
+	printf("data %"PRIuMAX"\n", (uintmax_t) log->len);
 	fwrite(log->buf, log->len, 1, stdout);
-	printf("%s\n", gitsvnline);
-	if (!first_commit_done) {
-		if (revision > 1)
-			printf("from :%"PRIu32"\n", revision - 1);
-		first_commit_done = 1;
-	}
+	putchar('\n');
+	if (from && *from)
+		printf("from %s\n", from);
 }
 
-void fast_export_end_commit(uint32_t revision)
+void fast_export_progress(uint32_t revision)
 {
 	printf("progress Imported commit %"PRIu32".\n\n", revision);
 }
diff --git a/vcs-svn/fast_export.h b/vcs-svn/fast_export.h
index 43d05b6..bf58880 100644
--- a/vcs-svn/fast_export.h
+++ b/vcs-svn/fast_export.h
@@ -10,10 +10,10 @@ void fast_export_reset(void);
 
 void fast_export_delete(const char *path);
 void fast_export_modify(const char *path, uint32_t mode, const char *dataref);
-void fast_export_begin_commit(uint32_t revision, const char *author,
-			const struct strbuf *log, const char *uuid,
-			const char *url, unsigned long timestamp);
-void fast_export_end_commit(uint32_t revision);
+void fast_export_begin_commit(const char *ref, uint32_t mark, const char *from,
+			const char *author_name, const char *author_email,
+			const struct strbuf *log, unsigned long timestamp);
+void fast_export_progress(uint32_t revision);
 void fast_export_data(uint32_t mode, uint32_t len, struct line_buffer *input);
 void fast_export_blob_delta(uint32_t mode,
 			uint32_t old_mode, const char *old_data,
diff --git a/vcs-svn/svndump.c b/vcs-svn/svndump.c
index 5cdf6b8..28d84c9 100644
--- a/vcs-svn/svndump.c
+++ b/vcs-svn/svndump.c
@@ -37,6 +37,8 @@
 #define LENGTH_UNKNOWN (~0)
 #define DATE_RFC2822_LEN 31
 
+#define MAX_GITSVN_LINE_LEN 4096
+
 static struct line_buffer input = LINE_BUFFER_INIT;
 
 static struct {
@@ -54,6 +56,7 @@ static struct {
 static struct {
 	uint32_t version;
 	struct strbuf uuid, url;
+	int first_commit_done;
 } dump_ctx;
 
 static void reset_node_ctx(char *fname)
@@ -86,6 +89,7 @@ static void reset_dump_ctx(const char *url)
 		strbuf_addstr(&dump_ctx.url, url);
 	dump_ctx.version = 1;
 	strbuf_reset(&dump_ctx.uuid);
+	dump_ctx.first_commit_done = 0;
 }
 
 static void handle_property(const struct strbuf *key_buf,
@@ -299,19 +303,49 @@ static void handle_node(void)
 				node_ctx.textLength, &input);
 }
 
+static void add_metadata_trailer(struct strbuf *buf)
+{
+	if (*dump_ctx.uuid.buf && *dump_ctx.url.buf)
+		strbuf_addf(buf, "\n\ngit-svn-id: %s@%"PRIu32" %s\n",
+			 dump_ctx.url.buf, rev_ctx.revision, dump_ctx.uuid.buf);
+}
+
 static void begin_revision(void)
 {
+	static struct strbuf email;
+	const char *author;
+	uint32_t prev;
+	char buf[32];
+
 	if (!rev_ctx.revision)	/* revision 0 gets no git commit. */
 		return;
-	fast_export_begin_commit(rev_ctx.revision, rev_ctx.author.buf,
-		&rev_ctx.log, dump_ctx.uuid.buf, dump_ctx.url.buf,
-		rev_ctx.timestamp);
+	prev = dump_ctx.first_commit_done ? rev_ctx.revision - 1 : 0;
+	if (prev)
+		snprintf(buf, 32, ":%"PRIu32, prev);
+	else
+		*buf = 0;
+	author = *rev_ctx.author.buf ? rev_ctx.author.buf : "nobody";
+
+	strbuf_reset(&email);
+	strbuf_addstr(&email, author);
+	strbuf_addch(&email, '@');
+	if (*dump_ctx.uuid.buf)
+		strbuf_addstr(&email, dump_ctx.uuid.buf);
+	else
+		strbuf_addstr(&email, "local");
+
+	add_metadata_trailer(&rev_ctx.log);
+
+	fast_export_begin_commit("refs/heads/master", rev_ctx.revision, buf,
+		author, email.buf, &rev_ctx.log, rev_ctx.timestamp);
 }
 
 static void end_revision(void)
 {
-	if (rev_ctx.revision)
-		fast_export_end_commit(rev_ctx.revision);
+	if (rev_ctx.revision) {
+		fast_export_progress(rev_ctx.revision);
+		dump_ctx.first_commit_done = 1;
+	}
 }
 
 void svndump_read(void)
-- 
1.7.3.4