diff-tree: clean up diff_tree_stdin() function

Split it into the "one commit" vs "two trees" case, since we'll
want to use the "one commit" case for other things too.

diff --git a/diff-tree.c b/diff-tree.c
index 51e3274..24b24dc 100644 (file)
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -342,27 +342,11 @@ static char *generate_header(const char *commit, const char *parent, const char
        return this_header;
 }
 
-static int diff_tree_stdin(char *line)
+static int diff_tree_commit(const unsigned char *commit, const char *name)
 {
-       int len = strlen(line);
-       unsigned char commit[20], parent[20];
        unsigned long size, offset;
-       static char this_header[1000];
-       char *buf;
+       char *buf = read_object_with_reference(commit, "commit", &size, NULL);
 
-       if (!len || line[len-1] != '\n')
-               return -1;
-       line[len-1] = 0;
-       if (get_sha1_hex(line, commit))
-               return -1;
-       if (isspace(line[40]) && !get_sha1_hex(line+41, parent)) {
-               line[40] = 0;
-               line[81] = 0;
-               sprintf(this_header, "%s (from %s)\n", line, line+41);
-               header = this_header;
-               return diff_tree_sha1(parent, commit, "");
-       }
-       buf = read_object_with_reference(commit, "commit", &size, NULL);
        if (!buf)
                return -1;
 
@@ -372,18 +356,40 @@ static int diff_tree_stdin(char *line)
                        return 0;
        }
 
-       line[40] = 0;
        offset = 46;
        while (offset + 48 < size && !memcmp(buf + offset, "parent ", 7)) {
+               unsigned char parent[20];
                if (get_sha1_hex(buf + offset + 7, parent))
                        return -1;
-               header = generate_header(line, sha1_to_hex(parent), buf, size);
+               header = generate_header(name, sha1_to_hex(parent), buf, size);
                diff_tree_sha1(parent, commit, "");
                if (!header && verbose_header)
                        header_prefix = "\ndiff-tree ";
                offset += 48;
        }
-       return -1;
+       return 0;
+}
+
+static int diff_tree_stdin(char *line)
+{
+       int len = strlen(line);
+       unsigned char commit[20], parent[20];
+       static char this_header[1000];
+
+       if (!len || line[len-1] != '\n')
+               return -1;
+       line[len-1] = 0;
+       if (get_sha1_hex(line, commit))
+               return -1;
+       if (isspace(line[40]) && !get_sha1_hex(line+41, parent)) {
+               line[40] = 0;
+               line[81] = 0;
+               sprintf(this_header, "%s (from %s)\n", line, line+41);
+               header = this_header;
+               return diff_tree_sha1(parent, commit, "");
+       }
+       line[40] = 0;
+       return diff_tree_commit(commit, line);
 }
 
 static char *diff_tree_usage =