Implement a remote helper for svn in C
Enable basic fetching from subversion repositories. When processing remote URLs starting with testsvn::, git invokes this remote-helper. It starts svnrdump to extract revisions from the subversion repository in the 'dump file format', and converts them to a git-fast-import stream using the functions of vcs-svn/. Imported refs are created in a private namespace at refs/svn/<remote-name>/master. The revision history is imported linearly (no branch detection) and completely, i.e. from revision 0 to HEAD. The 'bidi-import' capability is used. The remote-helper expects data from fast-import on its stdin. It buffers a batch of 'import' command lines in a string_list before starting to process them. Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com> Acked-by: David Michael Barr <b@rr-dav.id.au> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Florian Achleitner committed
Sep 19, 2012 at 17:21 UTC
68f64ff8b49ce5b32b11fe136ac89f0ba838a61c
1 file changed
+176
remote-testsvn.c
new
+176
@@ -0,0 +1,176 @@
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+#include "cache.h"
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+#include "remote.h"
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+#include "strbuf.h"
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+#include "url.h"
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+#include "exec_cmd.h"
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+#include "run-command.h"
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+#include "vcs-svn/svndump.h"
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+#include "notes.h"
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+#include "argv-array.h"
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+
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+static const char *url;
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+static const char *private_ref;
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+static const char *remote_ref = "refs/heads/master";
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+
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+static int cmd_capabilities(const char *line);
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+static int cmd_import(const char *line);
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+static int cmd_list(const char *line);
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+
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+typedef int (*input_command_handler)(const char *);
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+struct input_command_entry {
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+ const char *name;
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+ input_command_handler fn;
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+ unsigned char batchable; /* whether the command starts or is part of a batch */
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+};
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+
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+static const struct input_command_entry input_command_list[] = {
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+ { "capabilities", cmd_capabilities, 0 },
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+ { "import", cmd_import, 1 },
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+ { "list", cmd_list, 0 },
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+ { NULL, NULL }
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+};
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+
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+static int cmd_capabilities(const char *line)
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+{
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+ printf("import\n");
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+ printf("bidi-import\n");
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+ printf("refspec %s:%s\n\n", remote_ref, private_ref);
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+ fflush(stdout);
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+ return 0;
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+}
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+
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+static void terminate_batch(void)
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+{
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+ /* terminate a current batch's fast-import stream */
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+ printf("done\n");
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+ fflush(stdout);
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+}
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+
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+static int cmd_import(const char *line)
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+{
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+ int code;
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+ int dumpin_fd;
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+ unsigned int startrev = 0;
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+ struct argv_array svndump_argv = ARGV_ARRAY_INIT;
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+ struct child_process svndump_proc;
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+
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+ memset(&svndump_proc, 0, sizeof(struct child_process));
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+ svndump_proc.out = -1;
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+ argv_array_push(&svndump_argv, "svnrdump");
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+ argv_array_push(&svndump_argv, "dump");
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+ argv_array_push(&svndump_argv, url);
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+ argv_array_pushf(&svndump_argv, "-r%u:HEAD", startrev);
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+ svndump_proc.argv = svndump_argv.argv;
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+
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+ code = start_command(&svndump_proc);
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+ if (code)
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+ die("Unable to start %s, code %d", svndump_proc.argv[0], code);
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+ dumpin_fd = svndump_proc.out;
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+
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+ svndump_init_fd(dumpin_fd, STDIN_FILENO);
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+ svndump_read(url, private_ref);
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+ svndump_deinit();
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+ svndump_reset();
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+
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+ close(dumpin_fd);
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+ code = finish_command(&svndump_proc);
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+ if (code)
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+ warning("%s, returned %d", svndump_proc.argv[0], code);
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+ argv_array_clear(&svndump_argv);
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+
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+ return 0;
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+}
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+
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+static int cmd_list(const char *line)
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+{
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+ printf("? %s\n\n", remote_ref);
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+ fflush(stdout);
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+ return 0;
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+}
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+
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+static int do_command(struct strbuf *line)
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+{
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+ const struct input_command_entry *p = input_command_list;
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+ static struct string_list batchlines = STRING_LIST_INIT_DUP;
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+ static const struct input_command_entry *batch_cmd;
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+ /*
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+ * commands can be grouped together in a batch.
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+ * Batches are ended by \n. If no batch is active the program ends.
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+ * During a batch all lines are buffered and passed to the handler function
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+ * when the batch is terminated.
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+ */
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+ if (line->len == 0) {
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+ if (batch_cmd) {
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+ struct string_list_item *item;
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+ for_each_string_list_item(item, &batchlines)
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+ batch_cmd->fn(item->string);
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+ terminate_batch();
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+ batch_cmd = NULL;
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+ string_list_clear(&batchlines, 0);
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+ return 0; /* end of the batch, continue reading other commands. */
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+ }
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+ return 1; /* end of command stream, quit */
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+ }
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+ if (batch_cmd) {
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+ if (prefixcmp(batch_cmd->name, line->buf))
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+ die("Active %s batch interrupted by %s", batch_cmd->name, line->buf);
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+ /* buffer batch lines */
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+ string_list_append(&batchlines, line->buf);
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+ return 0;
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+ }
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+
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+ for (p = input_command_list; p->name; p++) {
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+ if (!prefixcmp(line->buf, p->name) && (strlen(p->name) == line->len ||
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+ line->buf[strlen(p->name)] == ' ')) {
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+ if (p->batchable) {
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+ batch_cmd = p;
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+ string_list_append(&batchlines, line->buf);
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+ return 0;
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+ }
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+ return p->fn(line->buf);
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+ }
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+ }
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+ die("Unknown command '%s'\n", line->buf);
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+ return 0;
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+}
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+
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+int main(int argc, const char **argv)
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+{
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+ struct strbuf buf = STRBUF_INIT, url_sb = STRBUF_INIT,
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+ private_ref_sb = STRBUF_INIT;
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+ static struct remote *remote;
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+ const char *url_in;
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+
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+ git_extract_argv0_path(argv[0]);
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+ setup_git_directory();
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+ if (argc < 2 || argc > 3) {
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+ usage("git-remote-svn <remote-name> [<url>]");
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+ return 1;
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+ }
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+
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+ remote = remote_get(argv[1]);
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+ url_in = (argc == 3) ? argv[2] : remote->url[0];
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+
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+ end_url_with_slash(&url_sb, url_in);
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+ url = url_sb.buf;
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+
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+ strbuf_addf(&private_ref_sb, "refs/svn/%s/master", remote->name);
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+ private_ref = private_ref_sb.buf;
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+
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+ while (1) {
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+ if (strbuf_getline(&buf, stdin, '\n') == EOF) {
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+ if (ferror(stdin))
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+ die("Error reading command stream");
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+ else
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+ die("Unexpected end of command stream");
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+ }
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+ if (do_command(&buf))
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+ break;
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+ strbuf_reset(&buf);
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+ }
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+
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+ strbuf_release(&buf);
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+ strbuf_release(&url_sb);
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+ strbuf_release(&private_ref_sb);
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+ return 0;
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+}