Merge branch 'db/vcs-svn-incremental' into svn-fe

This teaches svn-fe to incrementally import into an existing
repository (at last!) at the expense of less convenient UI.  Think of
it as growing pains.  This opens the door to many excellent things,
and it would be a bad idea to discourage people from building on it
for much longer.

* db/vcs-svn-incremental:
  vcs-svn: avoid using ls command twice
  vcs-svn: use mark from previous import for parent commit
  vcs-svn: handle filenames with dq correctly
  vcs-svn: quote paths correctly for ls command
  vcs-svn: eliminate repo_tree structure
  vcs-svn: add a comment before each commit
  vcs-svn: save marks for imported commits
  vcs-svn: use higher mark numbers for blobs
  vcs-svn: set up channel to read fast-import cat-blob response

Conflicts:
	t/t9010-svn-fe.sh
	vcs-svn/fast_export.c
	vcs-svn/fast_export.h
	vcs-svn/repo_tree.c
	vcs-svn/svndump.c

1 files changed, 129 insertions, 16 deletions

diff --git a/vcs-svn/fast_export.c b/vcs-svn/fast_export.c
index 99ed70b..ff980b3 100644
--- a/vcs-svn/fast_export.c
+++ b/vcs-svn/fast_export.c
@@ -8,30 +8,58 @@
 #include "line_buffer.h"
 #include "repo_tree.h"
 #include "string_pool.h"
+#include "strbuf.h"
 
 #define MAX_GITSVN_LINE_LEN 4096
 
 static uint32_t first_commit_done;
+static struct line_buffer report_buffer = LINE_BUFFER_INIT;
 
-void fast_export_delete(uint32_t depth, uint32_t *path)
+void fast_export_init(int fd)
 {
-	putchar('D');
-	putchar(' ');
-	pool_print_seq(depth, path, '/', stdout);
-	putchar('\n');
+	if (buffer_fdinit(&report_buffer, fd))
+		die_errno("cannot read from file descriptor %d", fd);
 }
 
-void fast_export_modify(uint32_t depth, uint32_t *path, uint32_t mode,
-			uint32_t mark)
+void fast_export_deinit(void)
+{
+	if (buffer_deinit(&report_buffer))
+		die_errno("error closing fast-import feedback stream");
+}
+
+void fast_export_reset(void)
+{
+	buffer_reset(&report_buffer);
+}
+
+void fast_export_delete(uint32_t depth, const uint32_t *path)
+{
+	printf("D \"");
+	pool_print_seq_q(depth, path, '/', stdout);
+	printf("\"\n");
+}
+
+static void fast_export_truncate(uint32_t depth, const uint32_t *path, uint32_t mode)
+{
+	fast_export_modify(depth, path, mode, "inline");
+	printf("data 0\n\n");
+}
+
+void fast_export_modify(uint32_t depth, const uint32_t *path, uint32_t mode,
+			const char *dataref)
 {
 	/* Mode must be 100644, 100755, 120000, or 160000. */
-	printf("M %06"PRIo32" :%"PRIu32" ", mode, mark);
-	pool_print_seq(depth, path, '/', stdout);
-	putchar('\n');
+	if (!dataref) {
+		fast_export_truncate(depth, path, mode);
+		return;
+	}
+	printf("M %06"PRIo32" %s \"", mode, dataref);
+	pool_print_seq_q(depth, path, '/', stdout);
+	printf("\"\n");
 }
 
 static char gitsvnline[MAX_GITSVN_LINE_LEN];
-void fast_export_commit(uint32_t revision, const char *author,
+void fast_export_begin_commit(uint32_t revision, const char *author,
 			const struct strbuf *log,
 			const char *uuid, const char *url,
 			unsigned long timestamp)
@@ -47,6 +75,7 @@ void fast_export_commit(uint32_t revision, const char *author,
 		*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",
@@ -57,15 +86,44 @@ void fast_export_commit(uint32_t revision, const char *author,
 	printf("%s\n", gitsvnline);
 	if (!first_commit_done) {
 		if (revision > 1)
-			printf("from refs/heads/master^0\n");
+			printf("from :%"PRIu32"\n", revision - 1);
 		first_commit_done = 1;
 	}
-	repo_diff(revision - 1, revision);
-	fputc('\n', stdout);
+}
 
+void fast_export_end_commit(uint32_t revision)
+{
 	printf("progress Imported commit %"PRIu32".\n\n", revision);
 }
 
+static void ls_from_rev(uint32_t rev, uint32_t depth, const uint32_t *path)
+{
+	/* ls :5 path/to/old/file */
+	printf("ls :%"PRIu32" \"", rev);
+	pool_print_seq_q(depth, path, '/', stdout);
+	printf("\"\n");
+	fflush(stdout);
+}
+
+static void ls_from_active_commit(uint32_t depth, const uint32_t *path)
+{
+	/* ls "path/to/file" */
+	printf("ls \"");
+	pool_print_seq_q(depth, path, '/', stdout);
+	printf("\"\n");
+	fflush(stdout);
+}
+
+static const char *get_response_line(void)
+{
+	const char *line = buffer_read_line(&report_buffer);
+	if (line)
+		return line;
+	if (buffer_ferror(&report_buffer))
+		die_errno("error reading from fast-import");
+	die("unexpected end of fast-import feedback");
+}
+
 static void die_short_read(struct line_buffer *input)
 {
 	if (buffer_ferror(input))
@@ -73,7 +131,7 @@ static void die_short_read(struct line_buffer *input)
 	die("invalid dump: unexpected end of file");
 }
 
-void fast_export_blob(uint32_t mode, uint32_t mark, uint32_t len, struct line_buffer *input)
+void fast_export_data(uint32_t mode, uint32_t len, struct line_buffer *input)
 {
 	if (mode == REPO_MODE_LNK) {
 		/* svn symlink blobs start with "link " */
@@ -81,8 +139,63 @@ void fast_export_blob(uint32_t mode, uint32_t mark, uint32_t len, struct line_bu
 		if (buffer_skip_bytes(input, 5) != 5)
 			die_short_read(input);
 	}
-	printf("blob\nmark :%"PRIu32"\ndata %"PRIu32"\n", mark, len);
+	printf("data %"PRIu32"\n", len);
 	if (buffer_copy_bytes(input, len) != len)
 		die_short_read(input);
 	fputc('\n', stdout);
 }
+
+static int parse_ls_response(const char *response, uint32_t *mode,
+					struct strbuf *dataref)
+{
+	const char *tab;
+	const char *response_end;
+
+	assert(response);
+	response_end = response + strlen(response);
+
+	if (*response == 'm') {	/* Missing. */
+		errno = ENOENT;
+		return -1;
+	}
+
+	/* Mode. */
+	if (response_end - response < strlen("100644") ||
+	    response[strlen("100644")] != ' ')
+		die("invalid ls response: missing mode: %s", response);
+	*mode = 0;
+	for (; *response != ' '; response++) {
+		char ch = *response;
+		if (ch < '0' || ch > '7')
+			die("invalid ls response: mode is not octal: %s", response);
+		*mode *= 8;
+		*mode += ch - '0';
+	}
+
+	/* ' blob ' or ' tree ' */
+	if (response_end - response < strlen(" blob ") ||
+	    (response[1] != 'b' && response[1] != 't'))
+		die("unexpected ls response: not a tree or blob: %s", response);
+	response += strlen(" blob ");
+
+	/* Dataref. */
+	tab = memchr(response, '\t', response_end - response);
+	if (!tab)
+		die("invalid ls response: missing tab: %s", response);
+	strbuf_add(dataref, response, tab - response);
+	return 0;
+}
+
+int fast_export_ls_rev(uint32_t rev, uint32_t depth, const uint32_t *path,
+				uint32_t *mode, struct strbuf *dataref)
+{
+	ls_from_rev(rev, depth, path);
+	return parse_ls_response(get_response_line(), mode, dataref);
+}
+
+int fast_export_ls(uint32_t depth, const uint32_t *path,
+				uint32_t *mode, struct strbuf *dataref)
+{
+	ls_from_active_commit(depth, path);
+	return parse_ls_response(get_response_line(), mode, dataref);
+}