diff: provide more context to the consumer of the callbacks

Update the callback to provide some information related to the file change being processed and the range of the hunk, when applicable.

include/git2/diff.h

@@ -154,19 +154,22 @@ typedef int (*git_diff_hunk_fn)(
  * Line origin constants.
  *
  * These values describe where a line came from and will be passed to
- * the git_diff_line_fn when iterating over a diff.  There are some
+ * the git_diff_data_fn when iterating over a diff.  There are some
  * special origin contants at the end that are used for the text
  * output callbacks to demarcate lines that are actually part of
  * the file or hunk headers.
  */
 enum {
-	/* these values will be sent to `git_diff_line_fn` along with the line */
+	/* these values will be sent to `git_diff_data_fn` along with the line */
 	GIT_DIFF_LINE_CONTEXT   = ' ',
 	GIT_DIFF_LINE_ADDITION  = '+',
 	GIT_DIFF_LINE_DELETION  = '-',
 	GIT_DIFF_LINE_ADD_EOFNL = '\n', /**< LF was added at end of file */
 	GIT_DIFF_LINE_DEL_EOFNL = '\0', /**< LF was removed at end of file */
-	/* these values will only be sent to a `git_diff_output_fn` */
+	/* these values will only be sent to a `git_diff_data_fn` when the content
+	 * of a diff is being formatted (eg. through git_diff_print_patch() or
+	 * git_diff_print_compact(), for instance).
+	 */
 	GIT_DIFF_LINE_FILE_HDR  = 'F',
 	GIT_DIFF_LINE_HUNK_HDR  = 'H',
 	GIT_DIFF_LINE_BINARY    = 'B'
@@ -174,25 +177,19 @@ enum {
 
 /**
  * When iterating over a diff, callback that will be made per text diff
- * line.
- */
-typedef int (*git_diff_line_fn)(
-	void *cb_data,
-	git_diff_delta *delta,
-	char line_origin, /**< GIT_DIFF_LINE_... value from above */
-	const char *content,
-	size_t content_len);
-
-/**
+ * line. In this context, the provided range will be NULL.
+ *
  * When printing a diff, callback that will be made to output each line
  * of text.  This uses some extra GIT_DIFF_LINE_... constants for output
  * of lines of file and hunk headers.
  */
-typedef int (*git_diff_output_fn)(
+typedef int (*git_diff_data_fn)(
 	void *cb_data,
+	git_diff_delta *delta,
+	git_diff_range *range,
 	char line_origin, /**< GIT_DIFF_LINE_... value from above */
-	const char *formatted_output);
-
+	const char *content,
+	size_t content_len);
 
 /** @name Diff List Generator Functions
  *
@@ -311,7 +308,7 @@ GIT_EXTERN(int) git_diff_foreach(
 	void *cb_data,
 	git_diff_file_fn file_cb,
 	git_diff_hunk_fn hunk_cb,
-	git_diff_line_fn line_cb);
+	git_diff_data_fn line_cb);
 
 /**
  * Iterate over a diff generating text output like "git diff --name-status".
@@ -319,7 +316,7 @@ GIT_EXTERN(int) git_diff_foreach(
 GIT_EXTERN(int) git_diff_print_compact(
 	git_diff_list *diff,
 	void *cb_data,
-	git_diff_output_fn print_cb);
+	git_diff_data_fn print_cb);
 
 /**
  * Iterate over a diff generating text output like "git diff".
@@ -329,7 +326,7 @@ GIT_EXTERN(int) git_diff_print_compact(
 GIT_EXTERN(int) git_diff_print_patch(
 	git_diff_list *diff,
 	void *cb_data,
-	git_diff_output_fn print_cb);
+	git_diff_data_fn print_cb);
 
 /**@}*/
 
@@ -348,7 +345,7 @@ GIT_EXTERN(int) git_diff_blobs(
 	git_diff_options *options,
 	void *cb_data,
 	git_diff_hunk_fn hunk_cb,
-	git_diff_line_fn line_cb);
+	git_diff_data_fn line_cb);
 
 GIT_END_DECL
 

src/diff_output.c

@@ -18,9 +18,10 @@ typedef struct {
 	git_diff_list *diff;
 	void *cb_data;
 	git_diff_hunk_fn hunk_cb;
-	git_diff_line_fn line_cb;
+	git_diff_data_fn line_cb;
 	unsigned int index;
 	git_diff_delta *delta;
+	git_diff_range range;
 } diff_output_info;
 
 static int read_next_int(const char **str, int *value)
@@ -62,6 +63,8 @@ static int diff_output_cb(void *priv, mmbuffer_t *bufs, int len)
 		if (range.old_start < 0 || range.new_start < 0)
 			return -1;
 
+		memcpy(&info->range, &range, sizeof(git_diff_range));
+
 		return info->hunk_cb(
 			info->cb_data, info->delta, &range, bufs[0].ptr, bufs[0].size);
 	}
@@ -76,7 +79,7 @@ static int diff_output_cb(void *priv, mmbuffer_t *bufs, int len)
 			GIT_DIFF_LINE_CONTEXT;
 
 		if (info->line_cb(
-			info->cb_data, info->delta, origin, bufs[1].ptr, bufs[1].size) < 0)
+			info->cb_data, info->delta, &info->range, origin, bufs[1].ptr, bufs[1].size) < 0)
 			return -1;
 
 		/* deal with adding and removing newline at EOF */
@@ -87,7 +90,7 @@ static int diff_output_cb(void *priv, mmbuffer_t *bufs, int len)
 				origin = GIT_DIFF_LINE_DEL_EOFNL;
 
 			return info->line_cb(
-				info->cb_data, info->delta, origin, bufs[2].ptr, bufs[2].size);
+				info->cb_data, info->delta, &info->range, origin, bufs[2].ptr, bufs[2].size);
 		}
 	}
 
@@ -291,7 +294,7 @@ int git_diff_foreach(
 	void *data,
 	git_diff_file_fn file_cb,
 	git_diff_hunk_fn hunk_cb,
-	git_diff_line_fn line_cb)
+	git_diff_data_fn line_cb)
 {
 	int error = 0;
 	diff_output_info info;
@@ -433,7 +436,7 @@ cleanup:
 
 typedef struct {
 	git_diff_list *diff;
-	git_diff_output_fn print_cb;
+	git_diff_data_fn print_cb;
 	void *cb_data;
 	git_buf *buf;
 } diff_print_info;
@@ -491,13 +494,13 @@ static int print_compact(void *data, git_diff_delta *delta, float progress)
 	if (git_buf_oom(pi->buf))
 		return -1;
 
-	return pi->print_cb(pi->cb_data, GIT_DIFF_LINE_FILE_HDR, pi->buf->ptr);
+	return pi->print_cb(pi->cb_data, delta, NULL, GIT_DIFF_LINE_FILE_HDR, git_buf_cstr(pi->buf), git_buf_len(pi->buf));
 }
 
 int git_diff_print_compact(
 	git_diff_list *diff,
 	void *cb_data,
-	git_diff_output_fn print_cb)
+	git_diff_data_fn print_cb)
 {
 	int error;
 	git_buf buf = GIT_BUF_INIT;
@@ -586,7 +589,7 @@ static int print_patch_file(void *data, git_diff_delta *delta, float progress)
 	if (git_buf_oom(pi->buf))
 		return -1;
 
-    result = pi->print_cb(pi->cb_data, GIT_DIFF_LINE_FILE_HDR, pi->buf->ptr);
+    result = pi->print_cb(pi->cb_data, delta, NULL, GIT_DIFF_LINE_FILE_HDR, git_buf_cstr(pi->buf), git_buf_len(pi->buf));
     if (result < 0)
         return result;
 
@@ -600,7 +603,7 @@ static int print_patch_file(void *data, git_diff_delta *delta, float progress)
 	if (git_buf_oom(pi->buf))
 		return -1;
 
-	return pi->print_cb(pi->cb_data, GIT_DIFF_LINE_BINARY, pi->buf->ptr);
+	return pi->print_cb(pi->cb_data, delta, NULL, GIT_DIFF_LINE_BINARY, git_buf_cstr(pi->buf), git_buf_len(pi->buf));
 }
 
 static int print_patch_hunk(
@@ -612,27 +615,23 @@ static int print_patch_hunk(
 {
 	diff_print_info *pi = data;
 
-	GIT_UNUSED(d);
-	GIT_UNUSED(r);
-
 	git_buf_clear(pi->buf);
 	if (git_buf_printf(pi->buf, "%.*s", (int)header_len, header) < 0)
 		return -1;
 
-	return pi->print_cb(pi->cb_data, GIT_DIFF_LINE_HUNK_HDR, pi->buf->ptr);
+	return pi->print_cb(pi->cb_data, d, r, GIT_DIFF_LINE_HUNK_HDR, git_buf_cstr(pi->buf), git_buf_len(pi->buf));
 }
 
 static int print_patch_line(
 	void *data,
 	git_diff_delta *delta,
+	git_diff_range *range,
 	char line_origin, /* GIT_DIFF_LINE value from above */
 	const char *content,
 	size_t content_len)
 {
 	diff_print_info *pi = data;
 
-	GIT_UNUSED(delta);
-
 	git_buf_clear(pi->buf);
 
 	if (line_origin == GIT_DIFF_LINE_ADDITION ||
@@ -645,13 +644,13 @@ static int print_patch_line(
 	if (git_buf_oom(pi->buf))
 		return -1;
 
-	return pi->print_cb(pi->cb_data, line_origin, pi->buf->ptr);
+	return pi->print_cb(pi->cb_data, delta, range, line_origin, git_buf_cstr(pi->buf), git_buf_len(pi->buf));
 }
 
 int git_diff_print_patch(
 	git_diff_list *diff,
 	void *cb_data,
-	git_diff_output_fn print_cb)
+	git_diff_data_fn print_cb)
 {
 	int error;
 	git_buf buf = GIT_BUF_INIT;
@@ -678,7 +677,7 @@ int git_diff_blobs(
 	git_diff_options *options,
 	void *cb_data,
 	git_diff_hunk_fn hunk_cb,
-	git_diff_line_fn line_cb)
+	git_diff_data_fn line_cb)
 {
 	diff_output_info info;
 	git_diff_delta delta;

tests-clar/diff/diff_helpers.c

@@ -60,12 +60,14 @@ int diff_hunk_fn(
 int diff_line_fn(
 	void *cb_data,
 	git_diff_delta *delta,
+	git_diff_range *range,
 	char line_origin,
 	const char *content,
 	size_t content_len)
 {
 	diff_expects *e = cb_data;
 	(void)delta;
+	(void)range;
 	(void)content;
 	(void)content_len;
 	e->lines++;

tests-clar/diff/diff_helpers.h

@@ -37,6 +37,7 @@ extern int diff_hunk_fn(
 extern int diff_line_fn(
 	void *cb_data,
 	git_diff_delta *delta,
+	git_diff_range *range,
 	char line_origin,
 	const char *content,
 	size_t content_len);

tests-clar/diff/patch.c

@@ -13,26 +13,56 @@ void test_diff_patch__cleanup(void)
 	cl_git_sandbox_cleanup();
 }
 
-#define EXPECTED_OUTPUT "diff --git a/subdir.txt b/subdir.txt\n" \
+#define EXPECTED_HEADER "diff --git a/subdir.txt b/subdir.txt\n" \
 	"deleted file mode 100644\n" \
 	"index e8ee89e..0000000\n" \
 	"--- a/subdir.txt\n" \
 	"+++ /dev/null\n"
 
+#define EXPECTED_HUNK "@@ -1,2 +0,0 @@\n"
+
 static int check_removal_cb(
 	void *cb_data,
+	git_diff_delta *delta,
+	git_diff_range *range,
 	char line_origin,
-	const char *formatted_output)
+	const char *formatted_output,
+	size_t output_len)
 {
 	GIT_UNUSED(cb_data);
 
-	if (line_origin != 'F')
-		return 0;
+	switch (line_origin) {
+	case GIT_DIFF_LINE_FILE_HDR:
+		cl_assert_equal_s(EXPECTED_HEADER, formatted_output);
+		cl_assert(range == NULL);
+		goto check_delta;
+
+	case GIT_DIFF_LINE_HUNK_HDR:
+		cl_assert_equal_s(EXPECTED_HUNK, formatted_output);
+		/* Fall through */
+
+	case GIT_DIFF_LINE_CONTEXT:
+	case GIT_DIFF_LINE_DELETION:
+		goto check_range;
+
+	default:
+		/* unexpected code path */
+		return -1;
+	}
+
+check_range:
+	cl_assert(range != NULL);
+	cl_assert_equal_i(1, range->old_start);
+	cl_assert_equal_i(2, range->old_lines);
+	cl_assert_equal_i(0, range->new_start);
+	cl_assert_equal_i(0, range->new_lines);
 
-	if (strcmp(EXPECTED_OUTPUT, formatted_output) == 0)
-		return 0;
+check_delta:
+	cl_assert_equal_s("subdir.txt", delta->old.path);
+	cl_assert_equal_s("subdir.txt", delta->new.path);
+	cl_assert_equal_i(GIT_DELTA_DELETED, delta->status);
 
-	return -1;
+	return 0;
 }
 
 void test_diff_patch__can_properly_display_the_removal_of_a_file(void)