4 files changed, 116 insertions, 11 deletions

diff --git a/source/shared.c b/source/shared.cindex c189b11..fcdcd24 100644--- a/source/shared.c+++ b/source/shared.c@@ -87,15 +87,19 @@ struct cgit_repo *cgit_get_repoinfo(const char *url) 	return NULL; } -void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options UNUSED, void *data)+void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options, void *data) { 	filepair_fn fn = *(filepair_fn *)data;+	const char *wanted = options->single_follow; 	int i;  	for (i = 0; i < q->nr; i++) { 		// An unmerged path has no single pair of blobs to show. 		if (q->queue[i]->status == 'U') 			continue;+		// A diff aimed at one path ran over the whole commit.+		if (wanted && strcmp(q->queue[i]->two->path, wanted))+			continue; 		fn(q->queue[i]); 	} }@@ -215,11 +219,48 @@ int cgit_diff_files(const struct object_id *old_oid, const struct object_id *new 	return 0; } +static void set_literal_item(struct pathspec_item *item, const char *path)+{+	int len = path ? strlen(path) : 0;++	// nowildcard_len matching len makes git treat the path as literal+	// rather than as a glob.+	*item = (struct pathspec_item){ .match = path, .len = len, .nowildcard_len = len };+}+ void cgit_diff_limit_path(struct diff_options *opt, const char *prefix) { 	cgit_literal_pathspec(&opt->pathspec, xmalloc(sizeof(struct pathspec_item)), xstrdup(prefix)); } +void cgit_diff_limit_rename(struct diff_options *opt, const char *path, const char *source)+{+	struct pathspec_item *items = xcalloc(2, sizeof(*items));++	set_literal_item(&items[0], xstrdup(path));+	set_literal_item(&items[1], xstrdup(source));+	opt->pathspec.nr = 2;+	opt->pathspec.items = items;+	opt->detect_rename = DIFF_DETECT_RENAME;+}++/*+ * Whether path names something other than a directory in the new tree that+ * the old tree lacks, which is where a rename lands.+ */+static int path_is_new(const struct object_id *old_oid, const struct object_id *new_oid,+	const char *path)+{+	struct object_id oid;+	unsigned short mode;++	if (!*path || !old_oid || is_null_oid(old_oid))+		return 0;+	if (get_tree_entry(the_repository, new_oid, path, &oid, &mode) || S_ISDIR(mode))+		return 0;+	return get_tree_entry(the_repository, old_oid, path, &oid, &mode) != 0;+}+ void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new_oid, 	filepair_fn fn, const char *prefix, int ignorews) {@@ -234,7 +275,12 @@ void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new 		DIFF_XDL_SET(&opt, IGNORE_WHITESPACE); 	opt.format_callback = cgit_diff_tree_cb; 	opt.format_callback_data = &fn;-	if (prefix)+	// The source of a rename lies outside a limit naming its destination,+	// so a new path is diffed across the whole commit instead, with+	// rename detection aimed at that path alone.+	if (prefix && path_is_new(old_oid, new_oid, prefix))+		opt.single_follow = prefix;+	else if (prefix) 		cgit_diff_limit_path(&opt, prefix); 	diff_setup_done(&opt); @@ -246,6 +292,29 @@ void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new 	diff_flush(&opt); } +// The old name cgit_rename_source's diff finds, which a filepair_fn has no+// other way to hand back.+static char *rename_source;++static void note_rename_source(struct diff_filepair *pair)+{+	if (pair->status == DIFF_STATUS_RENAMED && !rename_source)+		rename_source = xstrdup(pair->one->path);+}++char *cgit_rename_source(const struct object_id *old_oid, const struct object_id *new_oid,+	const char *path)+{+	char *source;++	if (!path_is_new(old_oid, new_oid, path))+		return NULL;+	cgit_diff_tree(old_oid, new_oid, note_rename_source, path, 0);+	source = rename_source;+	rename_source = NULL;+	return source;+}+ void cgit_diff_commit(struct commit *commit, filepair_fn fn, const char *prefix) { 	const struct object_id *old_oid = NULL;@@ -262,11 +331,7 @@ int cgit_blob_too_large(size_t size)  void cgit_literal_pathspec(struct pathspec *ps, struct pathspec_item *item, const char *path) {-	int len = path ? strlen(path) : 0;--	// nowildcard_len matching len makes git treat the path as literal-	// rather than as a glob.-	*item = (struct pathspec_item){ .match = path, .len = len, .nowildcard_len = len };+	set_literal_item(item, path); 	ps->nr = path ? 1 : 0; 	ps->items = item; }
diff --git a/source/shared.c b/source/shared.c
index c189b11..fcdcd24 100644
--- a/source/shared.c
+++ b/source/shared.c
@@ -87,15 +87,19 @@ struct cgit_repo *cgit_get_repoinfo(const char *url)
 	return NULL;
 }
 
-void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options UNUSED, void *data)
+void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options, void *data)
 {
 	filepair_fn fn = *(filepair_fn *)data;
+	const char *wanted = options->single_follow;
 	int i;
 
 	for (i = 0; i < q->nr; i++) {
 		// An unmerged path has no single pair of blobs to show.
 		if (q->queue[i]->status == 'U')
 			continue;
+		// A diff aimed at one path ran over the whole commit.
+		if (wanted && strcmp(q->queue[i]->two->path, wanted))
+			continue;
 		fn(q->queue[i]);
 	}
 }
@@ -215,11 +219,48 @@ int cgit_diff_files(const struct object_id *old_oid, const struct object_id *new
 	return 0;
 }
 
+static void set_literal_item(struct pathspec_item *item, const char *path)
+{
+	int len = path ? strlen(path) : 0;
+
+	// nowildcard_len matching len makes git treat the path as literal
+	// rather than as a glob.
+	*item = (struct pathspec_item){ .match = path, .len = len, .nowildcard_len = len };
+}
+
 void cgit_diff_limit_path(struct diff_options *opt, const char *prefix)
 {
 	cgit_literal_pathspec(&opt->pathspec, xmalloc(sizeof(struct pathspec_item)), xstrdup(prefix));
 }
 
+void cgit_diff_limit_rename(struct diff_options *opt, const char *path, const char *source)
+{
+	struct pathspec_item *items = xcalloc(2, sizeof(*items));
+
+	set_literal_item(&items[0], xstrdup(path));
+	set_literal_item(&items[1], xstrdup(source));
+	opt->pathspec.nr = 2;
+	opt->pathspec.items = items;
+	opt->detect_rename = DIFF_DETECT_RENAME;
+}
+
+/*
+ * Whether path names something other than a directory in the new tree that
+ * the old tree lacks, which is where a rename lands.
+ */
+static int path_is_new(const struct object_id *old_oid, const struct object_id *new_oid,
+	const char *path)
+{
+	struct object_id oid;
+	unsigned short mode;
+
+	if (!*path || !old_oid || is_null_oid(old_oid))
+		return 0;
+	if (get_tree_entry(the_repository, new_oid, path, &oid, &mode) || S_ISDIR(mode))
+		return 0;
+	return get_tree_entry(the_repository, old_oid, path, &oid, &mode) != 0;
+}
+
 void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new_oid,
 	filepair_fn fn, const char *prefix, int ignorews)
 {
@@ -234,7 +275,12 @@ void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new
 		DIFF_XDL_SET(&opt, IGNORE_WHITESPACE);
 	opt.format_callback = cgit_diff_tree_cb;
 	opt.format_callback_data = &fn;
-	if (prefix)
+	// The source of a rename lies outside a limit naming its destination,
+	// so a new path is diffed across the whole commit instead, with
+	// rename detection aimed at that path alone.
+	if (prefix && path_is_new(old_oid, new_oid, prefix))
+		opt.single_follow = prefix;
+	else if (prefix)
 		cgit_diff_limit_path(&opt, prefix);
 	diff_setup_done(&opt);
 
@@ -246,6 +292,29 @@ void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new
 	diff_flush(&opt);
 }
 
+// The old name cgit_rename_source's diff finds, which a filepair_fn has no
+// other way to hand back.
+static char *rename_source;
+
+static void note_rename_source(struct diff_filepair *pair)
+{
+	if (pair->status == DIFF_STATUS_RENAMED && !rename_source)
+		rename_source = xstrdup(pair->one->path);
+}
+
+char *cgit_rename_source(const struct object_id *old_oid, const struct object_id *new_oid,
+	const char *path)
+{
+	char *source;
+
+	if (!path_is_new(old_oid, new_oid, path))
+		return NULL;
+	cgit_diff_tree(old_oid, new_oid, note_rename_source, path, 0);
+	source = rename_source;
+	rename_source = NULL;
+	return source;
+}
+
 void cgit_diff_commit(struct commit *commit, filepair_fn fn, const char *prefix)
 {
 	const struct object_id *old_oid = NULL;
@@ -262,11 +331,7 @@ int cgit_blob_too_large(size_t size)
 
 void cgit_literal_pathspec(struct pathspec *ps, struct pathspec_item *item, const char *path)
 {
-	int len = path ? strlen(path) : 0;
-
-	// nowildcard_len matching len makes git treat the path as literal
-	// rather than as a glob.
-	*item = (struct pathspec_item){ .match = path, .len = len, .nowildcard_len = len };
+	set_literal_item(item, path);
 	ps->nr = path ? 1 : 0;
 	ps->items = item;
 }
diff --git a/source/shared.h b/source/shared.hindex f182962..b24c690 100644--- a/source/shared.h+++ b/source/shared.h@@ -25,8 +25,9 @@ extern struct cgit_repo *cgit_get_repoinfo(const char *url);  /*  * A diff format callback that hands each filepair to the filepair_fn data- * points at. ISO C has no conversion between a function pointer and void *,- * so the function travels by address.+ * points at, or only the pair landing on single_follow when that is set. ISO+ * C has no conversion between a function pointer and void *, so the function+ * travels by address.  */ extern void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options, void *data); @@ -45,6 +46,25 @@ extern int cgit_diff_files(const struct object_id *old_oid, const struct object_  */ extern void cgit_diff_limit_path(struct diff_options *opt, const char *prefix); +/*+ * Limit a diff to path and to source, the name it was renamed from, both+ * taken literally, with rename detection on so that git pairs the two.+ */+extern void cgit_diff_limit_rename(struct diff_options *opt, const char *path, const char *source);++/*+ * The name path had in the old tree when the change between the two trees+ * renamed it, or NULL when path is no renamed file's new name. The result is+ * the caller's to free.+ */+extern char *cgit_rename_source(const struct object_id *old_oid, const struct object_id *new_oid,+	const char *path);++/*+ * Hand fn each filepair between the two trees, limited to the paths below+ * prefix when one is given. A prefix naming a file the old tree lacks still+ * comes back as the rename that produced it.+ */ extern void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new_oid, 	filepair_fn fn, const char *prefix, int ignorews); extern void cgit_diff_commit(struct commit *commit, filepair_fn fn, const char *prefix);
diff --git a/source/shared.h b/source/shared.h
index f182962..b24c690 100644
--- a/source/shared.h
+++ b/source/shared.h
@@ -25,8 +25,9 @@ extern struct cgit_repo *cgit_get_repoinfo(const char *url);
 
 /*
  * A diff format callback that hands each filepair to the filepair_fn data
- * points at. ISO C has no conversion between a function pointer and void *,
- * so the function travels by address.
+ * points at, or only the pair landing on single_follow when that is set. ISO
+ * C has no conversion between a function pointer and void *, so the function
+ * travels by address.
  */
 extern void cgit_diff_tree_cb(struct diff_queue_struct *q, struct diff_options *options, void *data);
 
@@ -45,6 +46,25 @@ extern int cgit_diff_files(const struct object_id *old_oid, const struct object_
  */
 extern void cgit_diff_limit_path(struct diff_options *opt, const char *prefix);
 
+/*
+ * Limit a diff to path and to source, the name it was renamed from, both
+ * taken literally, with rename detection on so that git pairs the two.
+ */
+extern void cgit_diff_limit_rename(struct diff_options *opt, const char *path, const char *source);
+
+/*
+ * The name path had in the old tree when the change between the two trees
+ * renamed it, or NULL when path is no renamed file's new name. The result is
+ * the caller's to free.
+ */
+extern char *cgit_rename_source(const struct object_id *old_oid, const struct object_id *new_oid,
+	const char *path);
+
+/*
+ * Hand fn each filepair between the two trees, limited to the paths below
+ * prefix when one is given. A prefix naming a file the old tree lacks still
+ * comes back as the rename that produced it.
+ */
 extern void cgit_diff_tree(const struct object_id *old_oid, const struct object_id *new_oid,
 	filepair_fn fn, const char *prefix, int ignorews);
 extern void cgit_diff_commit(struct commit *commit, filepair_fn fn, const char *prefix);
diff --git a/source/ui-diff.c b/source/ui-diff.cindex 315a8f0..0e2e75e 100644--- a/source/ui-diff.c+++ b/source/ui-diff.c@@ -510,8 +510,15 @@ static void print_raw_patch(const struct object_id *old_tree_oid, const struct o 	repo_diff_setup(the_repository, &diffopt); 	diffopt.output_format = DIFF_FORMAT_PATCH; 	diffopt.flags.recursive = 1;-	if (prefix)-		cgit_diff_limit_path(&diffopt, prefix);+	if (prefix) {+		char *source = cgit_rename_source(old_tree_oid, new_tree_oid, prefix);++		if (source)+			cgit_diff_limit_rename(&diffopt, prefix, source);+		else+			cgit_diff_limit_path(&diffopt, prefix);+		free(source);+	} 	diff_setup_done(&diffopt);  	ctx.page.mimetype = "text/plain";
diff --git a/source/ui-diff.c b/source/ui-diff.c
index 315a8f0..0e2e75e 100644
--- a/source/ui-diff.c
+++ b/source/ui-diff.c
@@ -510,8 +510,15 @@ static void print_raw_patch(const struct object_id *old_tree_oid, const struct o
 	repo_diff_setup(the_repository, &diffopt);
 	diffopt.output_format = DIFF_FORMAT_PATCH;
 	diffopt.flags.recursive = 1;
-	if (prefix)
-		cgit_diff_limit_path(&diffopt, prefix);
+	if (prefix) {
+		char *source = cgit_rename_source(old_tree_oid, new_tree_oid, prefix);
+
+		if (source)
+			cgit_diff_limit_rename(&diffopt, prefix, source);
+		else
+			cgit_diff_limit_path(&diffopt, prefix);
+		free(source);
+	}
 	diff_setup_done(&diffopt);
 
 	ctx.page.mimetype = "text/plain";
diff --git a/source/ui-patch.c b/source/ui-patch.cindex 0fa9a2e..a60e7cc 100644--- a/source/ui-patch.c+++ b/source/ui-patch.c@@ -12,6 +12,7 @@ #include "html.h" #include "ui-patch.h" #include "ui-shared.h"+#include "shared.h"  // Room for two hex object ids, the two dots between them, and the null byte. #define REV_RANGE_LEN (2 * GIT_MAX_HEXSZ + 3)@@ -24,6 +25,7 @@ void cgit_print_patch(const char *new_rev, const char *old_rev, const char *pref 	struct strvec rev_argv = STRVEC_INIT; 	char rev_range[REV_RANGE_LEN]; 	const char *version;+	char *source = NULL;  	if (!new_rev) 		new_rev = ctx.qry.head;@@ -47,9 +49,20 @@ void cgit_print_patch(const char *new_rev, const char *old_rev, const char *pref 	else 		strvec_push(&rev_argv, "--format=format:From %H Mon Sep 17 00:00:00 2001%n" 			"From: %an%nDate: %aD%n%w(78,0,1)Subject: %s%n%n%w(0)%b");+	// A file the change renamed is limited by its old name as well, with+	// rename detection on, so that git pairs the two into the rename. That+	// name comes from the tree rather than the request, so it is matched+	// literally.+	if (prefix)+		source = cgit_rename_source(&old_oid, &new_oid, prefix);+	if (source)+		strvec_push(&rev_argv, "-M"); 	strvec_pushl(&rev_argv, rev_range, "--", NULL); 	if (prefix) 		strvec_push(&rev_argv, prefix);+	if (source)+		strvec_pushf(&rev_argv, ":(literal)%s", source);+	free(source);  	// Git inlines a blob up to its own big-file threshold, far past what 	// any other view inflates, so max-blob-size is applied through it.
diff --git a/source/ui-patch.c b/source/ui-patch.c
index 0fa9a2e..a60e7cc 100644
--- a/source/ui-patch.c
+++ b/source/ui-patch.c
@@ -12,6 +12,7 @@
 #include "html.h"
 #include "ui-patch.h"
 #include "ui-shared.h"
+#include "shared.h"
 
 // Room for two hex object ids, the two dots between them, and the null byte.
 #define REV_RANGE_LEN (2 * GIT_MAX_HEXSZ + 3)
@@ -24,6 +25,7 @@ void cgit_print_patch(const char *new_rev, const char *old_rev, const char *pref
 	struct strvec rev_argv = STRVEC_INIT;
 	char rev_range[REV_RANGE_LEN];
 	const char *version;
+	char *source = NULL;
 
 	if (!new_rev)
 		new_rev = ctx.qry.head;
@@ -47,9 +49,20 @@ void cgit_print_patch(const char *new_rev, const char *old_rev, const char *pref
 	else
 		strvec_push(&rev_argv, "--format=format:From %H Mon Sep 17 00:00:00 2001%n"
 			"From: %an%nDate: %aD%n%w(78,0,1)Subject: %s%n%n%w(0)%b");
+	// A file the change renamed is limited by its old name as well, with
+	// rename detection on, so that git pairs the two into the rename. That
+	// name comes from the tree rather than the request, so it is matched
+	// literally.
+	if (prefix)
+		source = cgit_rename_source(&old_oid, &new_oid, prefix);
+	if (source)
+		strvec_push(&rev_argv, "-M");
 	strvec_pushl(&rev_argv, rev_range, "--", NULL);
 	if (prefix)
 		strvec_push(&rev_argv, prefix);
+	if (source)
+		strvec_pushf(&rev_argv, ":(literal)%s", source);
+	free(source);
 
 	// Git inlines a blob up to its own big-file threshold, far past what
 	// any other view inflates, so max-blob-size is applied through it.