Add standard interface for file diff functions

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

2 files changed, 86 insertions, 0 deletions

diff --git a/cgit.h b/cgit.h
index 24b02d7..43de375 100644
--- a/cgit.h
+++ b/cgit.h
@@ -20,6 +20,7 @@
 
 typedef void (*configfn)(const char *name, const char *value);
 typedef void (*filepair_fn)(struct diff_filepair *pair);
+typedef void (*linediff_fn)(char *line, int len);
 
 struct cacheitem {
         char *name;
@@ -117,9 +118,15 @@ extern int chk_positive(int result, char *msg);
 extern int hextoint(char c);
 
 extern void *cgit_free_commitinfo(struct commitinfo *info);
+
+extern int cgit_diff_files(const unsigned char *old_sha1,
+                           const unsigned char *new_sha1,
+                           linediff_fn fn);
+
 extern void cgit_diff_tree(const unsigned char *old_sha1,
                            const unsigned char *new_sha1,
                            filepair_fn fn);
+
 extern void cgit_diff_commit(struct commit *commit, filepair_fn fn);
 
 extern char *fmt(const char *format,...);
diff --git a/shared.c b/shared.c
index f8a17b6..801f68d 100644
--- a/shared.c
+++ b/shared.c
@@ -207,6 +207,85 @@ void cgit_diff_tree_cb(struct diff_queue_struct *q,
         }
 }
 
+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)