add support for snapshot tarballs

- reworked cgit_print_snapshot to use a list of supported archivers and pick
	one for the suffix supplied
- moved printing of snaphot links into ui-snapshot and make it iterate through
	the said list

cgit.c

@@ -68,7 +68,7 @@ static void cgit_print_repo_page(struct cacheitem *item)
 	setenv("GIT_DIR", cgit_repo->path, 1);
 
 	if ((cgit_cmd == CMD_SNAPSHOT) && cgit_repo->snapshots) {
-		cgit_print_snapshot(item, cgit_query_sha1, "zip",
+		cgit_print_snapshot(item, cgit_query_sha1,
 				    cgit_repo->url, cgit_query_name);
 		return;
 	}

cgit.h

@@ -230,7 +230,7 @@ extern void cgit_print_tree(const char *rev, char *path);
 extern void cgit_print_commit(char *hex);
 extern void cgit_print_diff(const char *new_hex, const char *old_hex);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *hex,
-				const char *format, const char *prefix,
-				const char *filename);
+				const char *prefix, const char *filename);
+extern void cgit_print_snapshot_links(const char *repo, const char *hex);
 
 #endif /* CGIT_H */

ui-commit.c

@@ -139,7 +139,6 @@ void cgit_print_commit(char *hex)
 	struct commitinfo *info;
 	struct commit_list *p;
 	unsigned char sha1[20];
-	char *filename;
 	char *tmp;
 	int i;
 
@@ -196,11 +195,9 @@ void cgit_print_commit(char *hex)
 		html(")</td></tr>");
 	}
 	if (cgit_repo->snapshots) {
-		htmlf("<tr><th>download</th><td colspan='2' class='sha1'><a href='");
-		filename = fmt("%s-%s.zip", cgit_query_repo, hex);
-		html_attr(cgit_pageurl(cgit_query_repo, "snapshot",
-				       fmt("id=%s&amp;name=%s", hex, filename)));
-		htmlf("'>%s</a></td></tr>", filename);
+		html("<tr><th>download</th><td colspan='2' class='sha1'>");
+		cgit_print_snapshot_links(cgit_query_repo,hex);
+		html("</td></tr>");
 	}
 	html("</table>\n");
 	html("<div class='commit-subject'>");

ui-snapshot.c

@@ -8,40 +8,61 @@
 
 #include "cgit.h"
 
-static void cgit_print_zip(struct cacheitem *item, const char *hex, 
-			   const char *prefix, const char *filename)
+static const struct snapshot_archive_t {
+    	const char *suffix;
+	const char *mimetype;
+	write_archive_fn_t write_func;
+}	snapshot_archives[] = {
+	{ ".zip", "application/x-zip", write_zip_archive },
+	{ ".tar.gz", "application/x-gzip", write_tar_archive }
+};
+
+void cgit_print_snapshot(struct cacheitem *item, const char *hex, 
+			 const char *prefix, const char *filename)
 {
-	struct archiver_args args;
-	struct commit *commit;
-	unsigned char sha1[20];
+	int fnl = strlen(filename);
+	int f;
+    	for(f=0;f<(sizeof(snapshot_archives)/sizeof(*snapshot_archives));++f) {
+		const struct snapshot_archive_t* sat = &snapshot_archives[f];
+		int sl = strlen(sat->suffix);
+		if(fnl<sl || strcmp(&filename[fnl-sl],sat->suffix))
+			continue;
 
-	if (get_sha1(hex, sha1)) {
-		cgit_print_error(fmt("Bad object id: %s", hex));
-		return;
-	}
-	commit = lookup_commit_reference(sha1);
+		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;
+		}
+		commit = lookup_commit_reference(sha1);
+
+		if(!commit) {
+			cgit_print_error(fmt("Not a commit reference: %s", hex));
+			return;;
+		}
 
-	if (!commit) {
-		cgit_print_error(fmt("Not a commit reference: %s", hex));
+		memset(&args,0,sizeof(args));
+		args.base = fmt("%s/", prefix);
+		args.tree = commit->tree;
+
+		cgit_print_snapshot_start(sat->mimetype, filename, item);
+		(*sat->write_func)(&args);
 		return;
 	}
-
-	memset(&args, 0, sizeof(args));
-	args.base = fmt("%s/", prefix);
-	args.tree = commit->tree;
-	
-	cgit_print_snapshot_start("application/x-zip", filename, item);
-	write_zip_archive(&args);
+	cgit_print_error(fmt("Unsupported snapshot format: %s", filename));
 }
 
-
-void cgit_print_snapshot(struct cacheitem *item, const char *hex, 
-			 const char *format, const char *prefix,
-			 const char *filename)
+void cgit_print_snapshot_links(const char *repo,const char *hex)
 {
-	if (!strcmp(format, "zip"))
-		cgit_print_zip(item, hex, prefix, filename);
-	else
-		cgit_print_error(fmt("Unsupported snapshot format: %s", 
-				     format));
+    	char *filename;
+	int f;
+    	for(f=0;f<(sizeof(snapshot_archives)/sizeof(*snapshot_archives));++f) {
+		const struct snapshot_archive_t* sat = &snapshot_archives[f];
+		filename = fmt("%s-%s%s",repo,hex,sat->suffix);
+		htmlf("<a href='%s'>%s</a><br/>",
+			cgit_pageurl(repo,"snapshot",
+			    fmt("id=%s&amp;name=%s",hex,filename)), filename);
+	}
 }