ui-snapshot: improve extraction of revision from snapshot name

The modified get_ref_from_filename() supports the following snapshot
formats:
* $REV.$EXT
* $REPO[-_]*v?$REV.$EXT

This implies that the following urls will retrieve the expected revision:
* http://hjemli.net/git/cgit/snapshot/v0.8.1.tar.gz
* http://hjemli.net/git/cgit/snapshot/0.8.1.tar.gz
* http://hjemli.net/git/cgit/snapshot/cgit-0.8.1.tar.gz
* http://hjemli.net/git/cgit/snapshot/cgit-140012d7a8.tar.gz

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 37 insertions, 43 deletions

diff --git a/ui-snapshot.c b/ui-snapshot.c
index 76457d6..6f09151 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -21,178 +21,172 @@ static int write_compressed_tar_archive(struct archiver_args *args,const char *f
         stdout2 = chk_non_negative(dup(STDIN_FILENO), "Preserving STDOUT before compressing");
         chk_zero(pipe(rw), "Opening pipe from compressor subprocess");
         gzpid = chk_non_negative(fork(), "Forking compressor subprocess");
         if(gzpid==0) {
                 /* child */
                 chk_zero(close(rw[1]), "Closing write end of pipe in child");
                 chk_zero(close(STDIN_FILENO), "Closing STDIN");
                 chk_non_negative(dup2(rw[0],STDIN_FILENO), "Redirecting compressor input to stdin");
                 execlp(filter,filter,NULL);
                 _exit(-1);
         }
         /* parent */
         chk_zero(close(rw[0]), "Closing read end of pipe");
         chk_non_negative(dup2(rw[1],STDOUT_FILENO), "Redirecting output to compressor");
 
         rv = write_tar_archive(args);
 
         chk_zero(close(STDOUT_FILENO), "Closing STDOUT redirected to compressor");
         chk_non_negative(dup2(stdout2,STDOUT_FILENO), "Restoring uncompressed STDOUT");
         chk_zero(close(stdout2), "Closing uncompressed STDOUT");
         chk_zero(close(rw[1]), "Closing write end of pipe in parent");
         chk_positive(waitpid(gzpid,&status,0), "Waiting on compressor process");
         if(! ( WIFEXITED(status) && WEXITSTATUS(status)==0 ) )
                 cgit_print_error("Failed to compress archive");
 
         return rv;
 }
 
 static int write_tar_gzip_archive(struct archiver_args *args)
 {
         return write_compressed_tar_archive(args,"gzip");
 }
 
 static int write_tar_bzip2_archive(struct archiver_args *args)
 {
         return write_compressed_tar_archive(args,"bzip2");
 }
 
 const struct cgit_snapshot_format cgit_snapshot_formats[] = {
         { ".zip", "application/x-zip", write_zip_archive, 0x1 },
         { ".tar.gz", "application/x-tar", write_tar_gzip_archive, 0x2 },
         { ".tar.bz2", "application/x-tar", write_tar_bzip2_archive, 0x4 },
         { ".tar", "application/x-tar", write_tar_archive, 0x8 },
         {}
 };
 
 static const struct cgit_snapshot_format *get_format(const char *filename)
 {
         const struct cgit_snapshot_format *fmt;
         int fl, sl;
 
         fl = strlen(filename);
         for(fmt = cgit_snapshot_formats; fmt->suffix; fmt++) {
                 sl = strlen(fmt->suffix);
                 if (sl >= fl)
                         continue;
                 if (!strcmp(fmt->suffix, filename + fl - sl))
                         return fmt;
         }
         return NULL;
 }
 
 static int make_snapshot(const struct cgit_snapshot_format *format,
                          const char *hex, const char *prefix,
                          const char *filename)
 {
         struct archiver_args args;
         struct commit *commit;
         unsigned char sha1[20];
 
         if(get_sha1(hex, sha1)) {
                 cgit_print_error(fmt("Bad object id: %s", hex));
                 return 1;
         }
         commit = lookup_commit_reference(sha1);
         if(!commit) {
                 cgit_print_error(fmt("Not a commit reference: %s", hex));
                 return 1;
         }
         memset(&args, 0, sizeof(args));
         if (prefix) {
                 args.base = fmt("%s/", prefix);
                 args.baselen = strlen(prefix) + 1;
         } else {
                 args.base = "";
                 args.baselen = 0;
         }
         args.tree = commit->tree;
         args.time = commit->date;
         ctx.page.mimetype = xstrdup(format->mimetype);
         ctx.page.filename = xstrdup(filename);
         cgit_print_http_headers(&ctx);
         format->write_func(&args);
         return 0;
 }
 
-char *dwim_filename = NULL;
-const char *dwim_refname = NULL;
-
-static int ref_cb(const char *refname, const unsigned char *sha1, int flags,
-                  void *cb_data)
-{
-        const char *r = refname;
-        while (r && *r) {
-                fprintf(stderr, "  cmp %s with %s:", dwim_filename, r);
-                if (!strcmp(dwim_filename, r)) {
-                        fprintf(stderr, "MATCH!\n");
-                        dwim_refname = refname;
-                        return 1;
-                }
-                fprintf(stderr, "no match\n");
-                if (isdigit(*r))
-                        break;
-                r++;
-        }
-        return 0;
-}
-
-/* Try to guess the requested revision by combining repo name and tag name
- * and comparing this to the requested snapshot name. E.g. the requested
- * snapshot is "cgit-0.7.2.tar.gz" while repo name is "cgit" and tag name
- * is "v0.7.2". First, the reponame is stripped off, leaving "-0.7.2.tar.gz".
- * Next, any '-' and '_' characters are stripped, leaving "0.7.2.tar.gz".
- * Finally, the requested format suffix is removed and we end up with "0.7.2".
- * Then we test each tag against this dwimmed filename, and for each tag
- * we even try to remove any leading characters which are non-digits. I.e.
- * we first compare with "v0.7.2", then with "0.7.2" and we've got a match.
+/* Try to guess the requested revision from the requested snapshot name.
+ * First the format extension is stripped, e.g. "cgit-0.7.2.tar.gz" become
+ * "cgit-0.7.2". If this is a valid commit object name we've got a winner.
+ * Otherwise, if the snapshot name has a prefix matching the result from
+ * repo_basename(), we strip the basename and any following '-' and '_'
+ * characters ("cgit-0.7.2" -> "0.7.2") and check the resulting name once
+ * more. If this still isn't a valid commit object name, we check if pre-
+ * pending a 'v' to the remaining snapshot name ("0.7.2" -> "v0.7.2") gives
+ * us something valid.
  */
 static const char *get_ref_from_filename(const char *url, const char *filename,
-                                         const struct cgit_snapshot_format *fmt)
+                                         const struct cgit_snapshot_format *format)
 {
-        const char *reponame = cgit_repobasename(url);
-        fprintf(stderr, "reponame=%s, filename=%s\n", reponame, filename);
-        if (prefixcmp(filename, reponame))
-                return NULL;
-        filename += strlen(reponame);
-        while (filename && (*filename == '-' || *filename == '_'))
-                filename++;
-        dwim_filename = xstrdup(filename);
-        dwim_filename[strlen(filename) - strlen(fmt->suffix)] = '\0';
-        for_each_tag_ref(ref_cb, NULL);
-        return dwim_refname;
+        const char *reponame;
+        unsigned char sha1[20];
+        char *snapshot;
+
+        snapshot = xstrdup(filename);
+        snapshot[strlen(snapshot) - strlen(format->suffix)] = '\0';
+        fprintf(stderr, "snapshot=%s\n", snapshot);
+
+        if (get_sha1(snapshot, sha1) == 0)
+                return snapshot;
+
+        reponame = cgit_repobasename(url);
+        fprintf(stderr, "reponame=%s\n", reponame);
+        if (prefixcmp(snapshot, reponame) == 0) {
+                snapshot += strlen(reponame);
+                while (snapshot && (*snapshot == '-' || *snapshot == '_'))
+                        snapshot++;
+        }
+
+        if (get_sha1(snapshot, sha1) == 0)
+                return snapshot;
+
+        snapshot = fmt("v%s", snapshot);
+        if (get_sha1(snapshot, sha1) == 0)
+                return snapshot;
+
+        return NULL;
 }
 
 void cgit_print_snapshot(const char *head, const char *hex,
                          const char *filename, int snapshots, int dwim)
 {
         const struct cgit_snapshot_format* f;
         char *prefix = NULL;
 
         f = get_format(filename);
         if (!f) {
                 ctx.page.mimetype = "text/html";
                 cgit_print_http_headers(&ctx);
                 cgit_print_docstart(&ctx);
                 cgit_print_pageheader(&ctx);
                 cgit_print_error(fmt("Unsupported snapshot format: %s", filename));
                 cgit_print_docend();
                 return;
         }
 
         if (!hex && dwim) {
                 hex = get_ref_from_filename(ctx.repo->url, filename, f);
                 if (hex != NULL) {
                         prefix = xstrdup(filename);
                         prefix[strlen(filename) - strlen(f->suffix)] = '\0';
                 }
         }
 
         if (!hex)
                 hex = head;
 
         if (!prefix)
                 prefix = xstrdup(cgit_repobasename(ctx.repo->url));
 
         make_snapshot(f, hex, prefix, filename);
         free(prefix);
 }