WIPjc/diff-blobfind

5 files changed, 55 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index ee9d5eb11e..fdfa8f38f6 100644
--- a/Makefile
+++ b/Makefile
@@ -775,6 +775,7 @@ LIB_OBJS += date.o
 LIB_OBJS += decorate.o
 LIB_OBJS += diffcore-break.o
 LIB_OBJS += diffcore-delta.o
+LIB_OBJS += diffcore-blobfind.o
 LIB_OBJS += diffcore-order.o
 LIB_OBJS += diffcore-pickaxe.o
 LIB_OBJS += diffcore-rename.o
diff --git a/diff.c b/diff.c
index 0763e89263..8861f89ab1 100644
--- a/diff.c
+++ b/diff.c
@@ -4082,6 +4082,7 @@ void diff_setup(struct diff_options *options)
 	options->interhunkcontext = diff_interhunk_context_default;
 	options->ws_error_highlight = ws_error_highlight_default;
 	options->flags.rename_empty = 1;
+	options->blobfind = NULL;
 
 	/* pathchange left =NULL by default */
 	options->change = diff_change;
@@ -4487,6 +4488,19 @@ static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *ar
 	return 1;
 }
 
+static int parse_blobfind_opt(struct diff_options *opt, const char *arg)
+{
+	struct object_id oid;
+
+	if (get_oid_blob(arg, &oid) || sha1_object_info(oid.hash, NULL) != OBJ_BLOB)
+		return error("object '%s' is not a blob", arg);
+
+	if (!opt->blobfind)
+		opt->blobfind = xcalloc(1, sizeof(*opt->blobfind));
+	oidset_insert(opt->blobfind, &oid);
+	return 1;
+}
+
 int diff_opt_parse(struct diff_options *options,
 		   const char **av, int ac, const char *prefix)
 {
@@ -4736,7 +4750,8 @@ int diff_opt_parse(struct diff_options *options,
 	else if ((argcount = short_opt('O', av, &optarg))) {
 		options->orderfile = prefix_filename(prefix, optarg);
 		return argcount;
-	}
+	} else if (skip_prefix(arg, "--blobfind=", &arg))
+		return parse_blobfind_opt(options, arg);
 	else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
 		int offending = parse_diff_filter_opt(optarg, options);
 		if (offending)
@@ -5770,6 +5785,9 @@ void diffcore_std(struct diff_options *options)
 		diffcore_skip_stat_unmatch(options);
 	if (!options->found_follow) {
 		/* See try_to_follow_renames() in tree-diff.c */
+
+		if (options->blobfind)
+			diffcore_blobfind(options);
 		if (options->break_opt != -1)
 			diffcore_break(options->break_opt);
 		if (options->detect_rename)
diff --git a/diff.h b/diff.h
index 0fb18dd735..9178e498fa 100644
--- a/diff.h
+++ b/diff.h
@@ -7,6 +7,7 @@
 #include "tree-walk.h"
 #include "pathspec.h"
 #include "object.h"
+#include "oidset.h"
 
 struct rev_info;
 struct diff_options;
@@ -174,6 +175,8 @@ struct diff_options {
 	enum diff_words_type word_diff;
 	enum diff_submodule_format submodule_format;
 
+	struct oidset *blobfind;
+
 	/* this is set by diffcore for DIFF_FORMAT_PATCH */
 	int found_changes;
 
diff --git a/diffcore-blobfind.c b/diffcore-blobfind.c
new file mode 100644
index 0000000000..64bf6922b0
--- /dev/null
+++ b/diffcore-blobfind.c
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2017 Google Inc.
+ */
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+
+void diffcore_blobfind(struct diff_options *options)
+{
+	struct diff_queue_struct *q = &diff_queued_diff;
+	struct diff_queue_struct outq;
+	int i;
+
+	if (!options->blobfind)
+		BUG("blobfind oidset not initialized???");
+
+	DIFF_QUEUE_CLEAR(&outq);
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+
+		if (!DIFF_PAIR_UNMERGED(p) &&
+		    ((DIFF_FILE_VALID(p->one) &&
+		      oidset_contains(options->blobfind, &p->one->oid)) ||
+		     (DIFF_FILE_VALID(p->two) &&
+		      oidset_contains(options->blobfind, &p->two->oid))))
+			diff_q(&outq, p);
+		else
+			diff_free_filepair(p);
+	}
+	*q = outq;
+}
diff --git a/diffcore.h b/diffcore.h
index a30da161da..431917672f 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -107,6 +107,7 @@ extern struct diff_filepair *diff_queue(struct diff_queue_struct *,
 					struct diff_filespec *);
 extern void diff_q(struct diff_queue_struct *, struct diff_filepair *);
 
+extern void diffcore_blobfind(struct diff_options *);
 extern void diffcore_break(int);
 extern void diffcore_rename(struct diff_options *);
 extern void diffcore_merge_broken(void);