Add standard interface for file diff functions

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

1 files changed, 79 insertions, 0 deletions

diff --git a/shared.c b/shared.c
index f8a17b6..801f68d 100644
--- a/shared.c
+++ b/shared.c
@@ -162,79 +162,158 @@ void cgit_querystring_cb(const char *name, const char *value)
                 cgit_query_has_sha1 = 1;
         } else if (!strcmp(name, "id2")) {
                 cgit_query_sha2 = xstrdup(value);
                 cgit_query_has_sha1 = 1;
         } else if (!strcmp(name, "ofs")) {
                 cgit_query_ofs = atoi(value);
         } else if (!strcmp(name, "path")) {
                 cgit_query_path = xstrdup(value);
         } else if (!strcmp(name, "name")) {
                 cgit_query_name = xstrdup(value);
         }
 }
 
 void *cgit_free_commitinfo(struct commitinfo *info)
 {
         free(info->author);
         free(info->author_email);
         free(info->committer);
         free(info->committer_email);
         free(info->subject);
         free(info);
         return NULL;
 }
 
 int hextoint(char c)
 {
         if (c >= 'a' && c <= 'f')
                 return 10 + c - 'a';
         else if (c >= 'A' && c <= 'F')
                 return 10 + c - 'A';
         else if (c >= '0' && c <= '9')
                 return c - '0';
         else
                 return -1;
 }
 
 void cgit_diff_tree_cb(struct diff_queue_struct *q,
                        struct diff_options *options, void *data)
 {
         int i;
 
         for (i = 0; i < q->nr; i++) {
                 if (q->queue[i]->status == 'U')
                         continue;
                 ((filepair_fn)data)(q->queue[i]);
         }
 }
 
+static int load_mmfile(mmfile_t *file, const unsigned char *sha1)
+{
+        enum object_type type;
+
+        if (is_null_sha1(sha1)) {
+                file->ptr = (char *)"";
+                file->size = 0;
+        } else {
+                file->ptr = read_sha1_file(sha1, &type, &file->size);
+        }
+        return 1;
+}
+
+/*
+ * Receive diff-buffers from xdiff and concatenate them as
+ * needed across multiple callbacks.
+ *
+ * This is basically a copy of xdiff-interface.c/xdiff_outf(),
+ * ripped from git and modified to use globals instead of
+ * a special callback-struct.
+ */
+char *diffbuf = NULL;
+int buflen = 0;
+
+int filediff_cb(void *priv, mmbuffer_t *mb, int nbuf)
+{
+        int i;
+
+        for (i = 0; i < nbuf; i++) {
+                if (mb[i].ptr[mb[i].size-1] != '\n') {
+                        /* Incomplete line */
+                        diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
+                        memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
+                        buflen += mb[i].size;
+                        continue;
+                }
+
+                /* we have a complete line */
+                if (!diffbuf) {
+                        ((linediff_fn)priv)(mb[i].ptr, mb[i].size);
+                        continue;
+                }
+                diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
+                memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
+                ((linediff_fn)priv)(diffbuf, buflen + mb[i].size);
+                free(diffbuf);
+                diffbuf = NULL;
+                buflen = 0;
+        }
+        if (diffbuf) {
+                ((linediff_fn)priv)(diffbuf, buflen);
+                free(diffbuf);
+                diffbuf = NULL;
+                buflen = 0;
+        }
+        return 0;
+}
+
+int cgit_diff_files(const unsigned char *old_sha1,
+                     const unsigned char *new_sha1,
+                     linediff_fn fn)
+{
+        mmfile_t file1, file2;
+        xpparam_t diff_params;
+        xdemitconf_t emit_params;
+        xdemitcb_t emit_cb;
+
+        if (!load_mmfile(&file1, old_sha1) || !load_mmfile(&file2, new_sha1))
+                return 1;
+
+        diff_params.flags = XDF_NEED_MINIMAL;
+        emit_params.ctxlen = 3;
+        emit_params.flags = XDL_EMIT_FUNCNAMES;
+        emit_cb.outf = filediff_cb;
+        emit_cb.priv = fn;
+        xdl_diff(&file1, &file2, &diff_params, &emit_params, &emit_cb);
+        return 0;
+}
+
 void cgit_diff_tree(const unsigned char *old_sha1,
                     const unsigned char *new_sha1,
                     filepair_fn fn)
 {
         struct diff_options opt;
         int ret;
 
         diff_setup(&opt);
         opt.output_format = DIFF_FORMAT_CALLBACK;
         opt.detect_rename = 1;
         opt.recursive = 1;
         opt.format_callback = cgit_diff_tree_cb;
         opt.format_callback_data = fn;
         diff_setup_done(&opt);
 
         if (old_sha1)
                 ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
         else
                 ret = diff_root_tree_sha1(new_sha1, "", &opt);
         diffcore_std(&opt);
         diff_flush(&opt);
 }
 
 void cgit_diff_commit(struct commit *commit, filepair_fn fn)
 {
         unsigned char *old_sha1 = NULL;
 
         if (commit->parents)
                 old_sha1 = commit->parents->item->object.sha1;
         cgit_diff_tree(old_sha1, commit->object.sha1, fn);
 }