1 files changed, 47 insertions, 17 deletions

diff --git a/builtin/merge-file.c b/builtin/merge-file.c
index d7eb4c6540..832c93d8d5 100644
--- a/builtin/merge-file.c
+++ b/builtin/merge-file.c
@@ -1,5 +1,8 @@
 #include "builtin.h"
 #include "abspath.h"
+#include "hex.h"
+#include "object-name.h"
+#include "object-store.h"
 #include "config.h"
 #include "gettext.h"
 #include "setup.h"
@@ -31,10 +34,11 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	mmfile_t mmfs[3] = { 0 };
 	mmbuffer_t result = { 0 };
 	xmparam_t xmp = { 0 };
-	int ret = 0, i = 0, to_stdout = 0;
+	int ret = 0, i = 0, to_stdout = 0, object_id = 0;
 	int quiet = 0;
 	struct option options[] = {
 		OPT_BOOL('p', "stdout", &to_stdout, N_("send results to standard output")),
+		OPT_BOOL(0,   "object-id", &object_id, N_("use object IDs instead of filenames")),
 		OPT_SET_INT(0, "diff3", &xmp.style, N_("use a diff3 based merge"), XDL_MERGE_DIFF3),
 		OPT_SET_INT(0, "zdiff3", &xmp.style, N_("use a zealous diff3 based merge"),
 				XDL_MERGE_ZEALOUS_DIFF3),
@@ -71,8 +75,12 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 			return error_errno("failed to redirect stderr to /dev/null");
 	}
 
+	if (object_id)
+		setup_git_directory();
+
 	for (i = 0; i < 3; i++) {
 		char *fname;
+		struct object_id oid;
 		mmfile_t *mmf = mmfs + i;
 
 		if (!names[i])
@@ -80,12 +88,22 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 
 		fname = prefix_filename(prefix, argv[i]);
 
-		if (read_mmfile(mmf, fname))
+		if (object_id) {
+			if (repo_get_oid(the_repository, argv[i], &oid))
+				ret = error(_("object '%s' does not exist"),
+					      argv[i]);
+			else if (!oideq(&oid, the_hash_algo->empty_blob))
+				read_mmblob(mmf, &oid);
+			else
+				read_mmfile(mmf, "/dev/null");
+		} else if (read_mmfile(mmf, fname)) {
 			ret = -1;
-		else if (mmf->size > MAX_XDIFF_SIZE ||
-			 buffer_is_binary(mmf->ptr, mmf->size))
+		}
+		if (ret != -1 && (mmf->size > MAX_XDIFF_SIZE ||
+		    buffer_is_binary(mmf->ptr, mmf->size))) {
 			ret = error("Cannot merge binary files: %s",
 				    argv[i]);
+		}
 
 		free(fname);
 		if (ret)
@@ -99,20 +117,32 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	ret = xdl_merge(mmfs + 1, mmfs + 0, mmfs + 2, &xmp, &result);
 
 	if (ret >= 0) {
-		const char *filename = argv[0];
-		char *fpath = prefix_filename(prefix, argv[0]);
-		FILE *f = to_stdout ? stdout : fopen(fpath, "wb");
-
-		if (!f)
-			ret = error_errno("Could not open %s for writing",
-					  filename);
-		else if (result.size &&
-			 fwrite(result.ptr, result.size, 1, f) != 1)
-			ret = error_errno("Could not write to %s", filename);
-		else if (fclose(f))
-			ret = error_errno("Could not close %s", filename);
+		if (object_id && !to_stdout) {
+			struct object_id oid;
+			if (result.size) {
+				if (write_object_file(result.ptr, result.size, OBJ_BLOB, &oid) < 0)
+					ret = error(_("Could not write object file"));
+			} else {
+				oidcpy(&oid, the_hash_algo->empty_blob);
+			}
+			if (ret >= 0)
+				printf("%s\n", oid_to_hex(&oid));
+		} else {
+			const char *filename = argv[0];
+			char *fpath = prefix_filename(prefix, argv[0]);
+			FILE *f = to_stdout ? stdout : fopen(fpath, "wb");
+
+			if (!f)
+				ret = error_errno("Could not open %s for writing",
+						  filename);
+			else if (result.size &&
+				 fwrite(result.ptr, result.size, 1, f) != 1)
+				ret = error_errno("Could not write to %s", filename);
+			else if (fclose(f))
+				ret = error_errno("Could not close %s", filename);
+			free(fpath);
+		}
 		free(result.ptr);
-		free(fpath);
 	}
 
 	if (ret > 127)