Improved three-way blob merging code

diff --git a/merge-tree.c b/merge-tree.c
index fd0c2111c48dc13b9d0d713ec7aa4a181daedb6a..7cf00be6d51b17ca60979a9c856e67405906d9a7 100644 (file)
--- a/merge-tree.c
+++ b/merge-tree.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "tree-walk.h"
+#include "xdiff-interface.h"
 #include "blob.h"
 
 static const char merge_tree_usage[] = "git-merge-tree <base-tree> <branch1> <branch2>";
@@ -52,6 +53,77 @@ static const char *explanation(struct merge_list *entry)
        return "removed in remote";
 }
 
+extern void *merge_file(struct blob *, struct blob *, struct blob *, unsigned long *);
+
+static void *result(struct merge_list *entry, unsigned long *size)
+{
+       char type[20];
+       struct blob *base, *our, *their;
+
+       if (!entry->stage)
+               return read_sha1_file(entry->blob->object.sha1, type, size);
+       base = NULL;
+       if (entry->stage == 1) {
+               base = entry->blob;
+               entry = entry->link;
+       }
+       our = NULL;
+       if (entry && entry->stage == 2) {
+               our = entry->blob;
+               entry = entry->link;
+       }
+       their = NULL;
+       if (entry)
+               their = entry->blob;
+       return merge_file(base, our, their, size);
+}
+
+static void *origin(struct merge_list *entry, unsigned long *size)
+{
+       char type[20];
+       while (entry) {
+               if (entry->stage == 2)
+                       return read_sha1_file(entry->blob->object.sha1, type, size);
+               entry = entry->link;
+       }
+       return NULL;
+}
+
+static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+{
+       int i;
+       for (i = 0; i < nbuf; i++)
+               printf("%.*s", (int) mb[i].size, mb[i].ptr);
+       return 0;
+}
+
+static void show_diff(struct merge_list *entry)
+{
+       unsigned long size;
+       mmfile_t src, dst;
+       xpparam_t xpp;
+       xdemitconf_t xecfg;
+       xdemitcb_t ecb;
+
+       xpp.flags = XDF_NEED_MINIMAL;
+       xecfg.ctxlen = 3;
+       xecfg.flags = 0;
+       ecb.outf = show_outf;
+       ecb.priv = NULL;
+
+       src.ptr = origin(entry, &size);
+       if (!src.ptr)
+               size = 0;
+       src.size = size;
+       dst.ptr = result(entry, &size);
+       if (!dst.ptr)
+               size = 0;
+       dst.size = size;
+       xdl_diff(&src, &dst, &xpp, &xecfg, &ecb);
+       free(src.ptr);
+       free(dst.ptr);
+}
+
 static void show_result_list(struct merge_list *entry)
 {
        printf("%s\n", explanation(entry));
@@ -70,6 +142,7 @@ static void show_result(void)
        walk = merge_result;
        while (walk) {
                show_result_list(walk);
+               show_diff(walk);
                walk = walk->next;
        }
 }