Add plain patch view

The new view mimics the output from `git format-patch`, making it possible
to cherry-pick directly from cgit with something like `curl $url | git am`.

Inspired by a patch to `git-apply` by Mike Hommey:
  http://thread.gmane.org/gmane.comp.version-control.git/67611/focus=67610

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

6 files changed, 122 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 72c189c..eed59df 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ GIT_URL = http://www.kernel.org/pub/software/scm/git/git-$(GIT_VER).tar.bz2
 EXTLIBS = git/libgit.a git/xdiff/lib.a -lz -lcrypto
 OBJECTS = shared.o cache.o parsing.o html.o ui-shared.o ui-repolist.o \
 	ui-summary.o ui-log.o ui-tree.o ui-commit.o ui-diff.o \
-	ui-snapshot.o ui-blob.o ui-tag.o ui-refs.o
+	ui-snapshot.o ui-blob.o ui-tag.o ui-refs.o ui-patch.o
 
 
 ifdef NEEDS_LIBICONV
diff --git a/cgit.c b/cgit.c
index 142e416..9ca93a7 100644
--- a/cgit.c
+++ b/cgit.c
@@ -75,6 +75,11 @@ static void cgit_print_repo_page(struct cacheitem *item)
 		return;
 	}
 
+	if (cgit_cmd == CMD_PATCH) {
+		cgit_print_patch(cgit_query_sha1, item);
+		return;
+	}
+
 	if (cgit_cmd == CMD_BLOB) {
 		cgit_print_blob(item, cgit_query_sha1, cgit_query_path);
 		return;
diff --git a/cgit.h b/cgit.h
index f223dbc..66c40b9 100644
--- a/cgit.h
+++ b/cgit.h
@@ -30,6 +30,7 @@
 #define CMD_SNAPSHOT 6
 #define CMD_TAG      7
 #define CMD_REFS     8
+#define CMD_PATCH    9
 
 /*
  * Dateformats used on misc. pages
@@ -283,6 +284,7 @@ extern void cgit_print_commit(char *hex);
 extern void cgit_print_refs();
 extern void cgit_print_tag(char *revname);
 extern void cgit_print_diff(const char *new_hex, const char *old_hex, const char *prefix);
+extern void cgit_print_patch(char *hex, struct cacheitem *item);
 extern void cgit_print_snapshot(struct cacheitem *item, const char *head,
 				const char *hex, const char *prefix,
 				const char *filename, int snapshot);
diff --git a/shared.c b/shared.c
index 2c309f5..9c992c8 100644
--- a/shared.c
+++ b/shared.c
@@ -70,7 +70,7 @@ int htmlfd = 0;
 int cgit_get_cmd_index(const char *cmd)
 {
 	static char *cmds[] = {"log", "commit", "diff", "tree", "blob",
-			       "snapshot", "tag", "refs", NULL};
+			       "snapshot", "tag", "refs", "patch", NULL};
 	int i;
 
 	for(i = 0; cmds[i]; i++)
diff --git a/ui-patch.c b/ui-patch.c
new file mode 100644
index 0000000..ef79c7c
--- /dev/null
+++ b/ui-patch.c
@@ -0,0 +1,105 @@
+/* ui-patch.c: generate patch view
+ *
+ * Copyright (C) 2007 Lars Hjemli
+ *
+ * Licensed under GNU General Public License v2
+ *   (see COPYING for full license text)
+ */
+
+#include "cgit.h"
+
+static void print_line(char *line, int len)
+{
+	char c = line[len-1];
+
+	line[len-1] = '\0';
+	htmlf("%s\n", line);
+	line[len-1] = c;
+}
+
+static void header(unsigned char *sha1, char *path1, int mode1,
+		   unsigned char *sha2, char *path2, int mode2)
+{
+	char *abbrev1, *abbrev2;
+	int subproject;
+
+	subproject = (S_ISGITLINK(mode1) || S_ISGITLINK(mode2));
+	htmlf("diff --git a/%s b/%s\n", path1, path2);
+
+	if (is_null_sha1(sha1))
+		path1 = "dev/null";
+	if (is_null_sha1(sha2))
+		path2 = "dev/null";
+
+	if (mode1 == 0)
+		htmlf("new file mode %.6o\n", mode2);
+
+	if (mode2 == 0)
+		htmlf("deleted file mode %.6o\n", mode1);
+
+	if (!subproject) {
+		abbrev1 = xstrdup(find_unique_abbrev(sha1, DEFAULT_ABBREV));
+		abbrev2 = xstrdup(find_unique_abbrev(sha2, DEFAULT_ABBREV));
+		htmlf("index %s..%s", abbrev1, abbrev2);
+		free(abbrev1);
+		free(abbrev2);
+		if (mode1 != 0 && mode2 != 0) {
+			htmlf(" %.6o", mode1);
+			if (mode2 != mode1)
+				htmlf("..%.6o", mode2);
+		}
+		htmlf("\n--- a/%s\n", path1);
+		htmlf("+++ b/%s\n", path2);
+	}
+}
+
+static void filepair_cb(struct diff_filepair *pair)
+{
+	header(pair->one->sha1, pair->one->path, pair->one->mode,
+	       pair->two->sha1, pair->two->path, pair->two->mode);
+	if (S_ISGITLINK(pair->one->mode) || S_ISGITLINK(pair->two->mode)) {
+		if (S_ISGITLINK(pair->one->mode))
+			print_line(fmt("-Subproject %s", sha1_to_hex(pair->one->sha1)), 52);
+		if (S_ISGITLINK(pair->two->mode))
+			print_line(fmt("+Subproject %s", sha1_to_hex(pair->two->sha1)), 52);
+		return;
+	}
+	if (cgit_diff_files(pair->one->sha1, pair->two->sha1, print_line))
+		html("Error running diff");
+}
+
+void cgit_print_patch(char *hex, struct cacheitem *item)
+{
+	struct commit *commit;
+	struct commitinfo *info;
+	unsigned char sha1[20], old_sha1[20];
+	char *patchname;
+
+	if (!hex)
+		hex = cgit_query_head;
+
+	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("Bad commit reference: %s", hex));
+		return;
+	}
+	info = cgit_parse_commit(commit);
+	hashcpy(old_sha1, commit->parents->item->object.sha1);
+
+	patchname = fmt("%s.patch", sha1_to_hex(sha1));
+	cgit_print_snapshot_start("text/plain", patchname, item);
+	htmlf("From %s Mon Sep 17 00:00:00 2001\n", sha1_to_hex(sha1));
+	htmlf("From: %s%s\n", info->author, info->author_email);
+	html("Date: ");
+	cgit_print_date(info->author_date, "%a, %d  %b  %Y  %H:%M:%S  %z%n");
+	htmlf("Subject: %s\n\n%s", info->subject, info->msg);
+	html("---\n");
+	cgit_diff_tree(old_sha1, sha1, filepair_cb, NULL);
+	html("--\n");
+	htmlf("cgit %s\n", CGIT_VERSION);
+	cgit_free_commitinfo(info);
+}
diff --git a/ui-shared.c b/ui-shared.c
index ece041c..60aa2e3 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -272,6 +272,12 @@ void cgit_diff_link(char *name, char *title, char *class, char *head,
 	html("</a>");
 }
 
+void cgit_patch_link(char *name, char *title, char *class, char *head,
+		     char *rev)
+{
+	reporevlink("patch", name, title, class, head, rev, NULL);
+}
+
 void cgit_object_link(struct object *obj)
 {
 	char *page, *arg, *url;
@@ -490,6 +496,8 @@ void cgit_print_pageheader(char *title, int show_search)
 			      cgit_query_sha1);
 		cgit_diff_link("diff", NULL, "menu", cgit_query_head,
 			       cgit_query_sha1, cgit_query_sha2, NULL);
+		cgit_patch_link("patch", NULL, "menu", cgit_query_head,
+				cgit_query_sha1);
 
 		for_each_ref(print_archive_ref, &header);