Add hunk/file headers to git_diff_patch_size

This allows git_diff_patch_size to account for hunk headers and
file headers in the returned size.  This required some refactoring
of the code that is used to print file headers so that it could be
invoked by the git_diff_patch_size API.

Also this increases the test coverage and fixes an off-by-one bug
in the size calculation when newline changes happen at the end of
the file.

include/git2/diff.h

@@ -391,7 +391,7 @@ typedef enum {
 	 */
 	GIT_DIFF_LINE_FILE_HDR  = 'F',
 	GIT_DIFF_LINE_HUNK_HDR  = 'H',
-	GIT_DIFF_LINE_BINARY    = 'B'
+	GIT_DIFF_LINE_BINARY    = 'B'  /**< Deprecated, will not be returned */
 } git_diff_line_t;
 
 /**
@@ -954,11 +954,15 @@ GIT_EXTERN(int) git_diff_patch_get_line_in_hunk(
  *
  * @param patch A git_diff_patch representing changes to one file
  * @param include_context Include context lines in size if non-zero
+ * @param include_hunk_headers Include hunk header lines if non-zero
+ * @param include_file_headers Include file header lines if non-zero
  * @return The number of bytes of data
  */
 GIT_EXTERN(size_t) git_diff_patch_size(
 	git_diff_patch *patch,
-	int include_context);
+	int include_context,
+	int include_hunk_headers,
+	int include_file_headers);
 
 /**
  * Serialize the patch to text via callback.

src/diff.h

@@ -81,6 +81,13 @@ extern const char *git_diff_delta__path(const git_diff_delta *delta);
 extern bool git_diff_delta__should_skip(
 	const git_diff_options *opts, const git_diff_delta *delta);
 
+extern int git_diff_delta__format_file_header(
+	git_buf *out,
+	const git_diff_delta *delta,
+	const char *oldpfx,
+	const char *newpfx,
+	int oid_strlen);
+
 extern int git_diff__oid_for_file(
 	git_repository *, const char *, uint16_t, git_off_t, git_oid *);
 

src/diff_patch.c

@@ -42,7 +42,7 @@ struct git_diff_patch {
 	git_array_t(diff_patch_hunk) hunks;
 	git_array_t(diff_patch_line) lines;
 	size_t oldno, newno;
-	size_t content_size, context_size;
+	size_t content_size, context_size, header_size;
 	git_pool flattened;
 };
 
@@ -806,7 +806,11 @@ notfound:
 	return diff_error_outofrange(thing);
 }
 
-size_t git_diff_patch_size(git_diff_patch *patch, int include_context)
+size_t git_diff_patch_size(
+	git_diff_patch *patch,
+	int include_context,
+	int include_hunk_headers,
+	int include_file_headers)
 {
 	size_t out;
 
@@ -817,6 +821,21 @@ size_t git_diff_patch_size(git_diff_patch *patch, int include_context)
 	if (!include_context)
 		out -= patch->context_size;
 
+	if (include_hunk_headers)
+		out += patch->header_size;
+
+	if (include_file_headers) {
+		git_buf file_header = GIT_BUF_INIT;
+
+		if (git_diff_delta__format_file_header(
+				&file_header, patch->delta, NULL, NULL, 0) < 0)
+			giterr_clear();
+		else
+			out += git_buf_len(&file_header);
+
+		git_buf_free(&file_header);
+	}
+
 	return out;
 }
 
@@ -914,6 +933,8 @@ static int diff_patch_hunk_cb(
 	hunk->header[header_len] = '\0';
 	hunk->header_len = header_len;
 
+	patch->header_size += header_len;
+
 	hunk->line_start = git_array_size(patch->lines);
 	hunk->line_count = 0;
 
@@ -934,6 +955,7 @@ static int diff_patch_line_cb(
 	git_diff_patch *patch = payload;
 	diff_patch_hunk *hunk;
 	diff_patch_line *line;
+	const char *content_end = content + content_len;
 
 	GIT_UNUSED(delta);
 	GIT_UNUSED(range);
@@ -948,38 +970,43 @@ static int diff_patch_line_cb(
 	line->len = content_len;
 	line->origin = line_origin;
 
-	patch->content_size += content_len + 1; /* +1 for line_origin */
-
-	if (line_origin == GIT_DIFF_LINE_CONTEXT ||
-		line_origin == GIT_DIFF_LINE_CONTEXT_EOFNL)
-		patch->context_size += content_len + 1;
-
 	/* do some bookkeeping so we can provide old/new line numbers */
 
-	for (line->lines = 0; content_len > 0; --content_len) {
+	line->lines = 0;
+	while (content < content_end)
 		if (*content++ == '\n')
 			++line->lines;
-	}
+
+	patch->content_size += content_len;
 
 	switch (line_origin) {
 	case GIT_DIFF_LINE_ADDITION:
+		patch->content_size += 1;
 	case GIT_DIFF_LINE_DEL_EOFNL:
 		line->oldno = -1;
 		line->newno = patch->newno;
 		patch->newno += line->lines;
 		break;
 	case GIT_DIFF_LINE_DELETION:
+		patch->content_size += 1;
 	case GIT_DIFF_LINE_ADD_EOFNL:
 		line->oldno = patch->oldno;
 		line->newno = -1;
 		patch->oldno += line->lines;
 		break;
-	default:
+	case GIT_DIFF_LINE_CONTEXT:
+		patch->content_size += 1;
+		patch->context_size += 1;
+	case GIT_DIFF_LINE_CONTEXT_EOFNL:
+		patch->context_size += content_len;
 		line->oldno = patch->oldno;
 		line->newno = patch->newno;
 		patch->oldno += line->lines;
 		patch->newno += line->lines;
 		break;
+	default:
+		assert(false);
+		break;
 	}
 
 	hunk->line_count++;

src/diff_print.c

@@ -198,13 +198,13 @@ int git_diff_print_raw(
 	return error;
 }
 
-static int diff_print_oid_range(diff_print_info *pi, const git_diff_delta *delta)
+static int diff_print_oid_range(
+	git_buf *out, const git_diff_delta *delta, int oid_strlen)
 {
-	git_buf *out = pi->buf;
 	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
 
-	git_oid_tostr(start_oid, pi->oid_strlen, &delta->old_file.oid);
-	git_oid_tostr(end_oid, pi->oid_strlen, &delta->new_file.oid);
+	git_oid_tostr(start_oid, oid_strlen, &delta->old_file.oid);
+	git_oid_tostr(end_oid, oid_strlen, &delta->new_file.oid);
 
 	/* TODO: Match git diff more closely */
 	if (delta->old_file.mode == delta->new_file.mode) {
@@ -228,35 +228,29 @@ static int diff_print_oid_range(diff_print_info *pi, const git_diff_delta *delta
 	return 0;
 }
 
-static int diff_print_patch_file(
-	const git_diff_delta *delta, float progress, void *data)
+int git_diff_delta__format_file_header(
+	git_buf *out,
+	const git_diff_delta *delta,
+	const char *oldpfx,
+	const char *newpfx,
+	int oid_strlen)
 {
-	diff_print_info *pi = data;
-	const char *oldpfx = pi->diff ? pi->diff->opts.old_prefix : NULL;
 	const char *oldpath = delta->old_file.path;
-	const char *newpfx = pi->diff ? pi->diff->opts.new_prefix : NULL;
 	const char *newpath = delta->new_file.path;
-	uint32_t opts_flags = pi->diff ? pi->diff->opts.flags : GIT_DIFF_NORMAL;
-
-	GIT_UNUSED(progress);
-
-	if (S_ISDIR(delta->new_file.mode) ||
-		delta->status == GIT_DELTA_UNMODIFIED ||
-		delta->status == GIT_DELTA_IGNORED ||
-		(delta->status == GIT_DELTA_UNTRACKED &&
-		 (opts_flags & GIT_DIFF_INCLUDE_UNTRACKED_CONTENT) == 0))
-		return 0;
 
 	if (!oldpfx)
 		oldpfx = DIFF_OLD_PREFIX_DEFAULT;
 	if (!newpfx)
 		newpfx = DIFF_NEW_PREFIX_DEFAULT;
+	if (!oid_strlen)
+		oid_strlen = GIT_ABBREV_DEFAULT + 1;
 
-	git_buf_clear(pi->buf);
-	git_buf_printf(pi->buf, "diff --git %s%s %s%s\n",
-		oldpfx, delta->old_file.path, newpfx, delta->new_file.path);
+	git_buf_clear(out);
+
+	git_buf_printf(out, "diff --git %s%s %s%s\n",
+		oldpfx, oldpath, newpfx, newpath);
 
-	if (diff_print_oid_range(pi, delta) < 0)
+	if (diff_print_oid_range(out, delta, oid_strlen) < 0)
 		return -1;
 
 	if (git_oid_iszero(&delta->old_file.oid)) {
@@ -269,28 +263,39 @@ static int diff_print_patch_file(
 	}
 
 	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0) {
-		git_buf_printf(pi->buf, "--- %s%s\n", oldpfx, oldpath);
-		git_buf_printf(pi->buf, "+++ %s%s\n", newpfx, newpath);
+		git_buf_printf(out, "--- %s%s\n", oldpfx, oldpath);
+		git_buf_printf(out, "+++ %s%s\n", newpfx, newpath);
+	} else {
+		git_buf_printf(
+			out, "Binary files %s%s and %s%s differ\n",
+			oldpfx, oldpath, newpfx, newpath);
 	}
 
-	if (git_buf_oom(pi->buf))
-		return -1;
+	return git_buf_oom(out) ? -1 : 0;
+}
 
-	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
-			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
-		return callback_error();
+static int diff_print_patch_file(
+	const git_diff_delta *delta, float progress, void *data)
+{
+	diff_print_info *pi = data;
+	const char *oldpfx = pi->diff ? pi->diff->opts.old_prefix : NULL;
+	const char *newpfx = pi->diff ? pi->diff->opts.new_prefix : NULL;
+	uint32_t opts_flags = pi->diff ? pi->diff->opts.flags : GIT_DIFF_NORMAL;
 
-	if ((delta->flags & GIT_DIFF_FLAG_BINARY) == 0)
+	GIT_UNUSED(progress);
+
+	if (S_ISDIR(delta->new_file.mode) ||
+		delta->status == GIT_DELTA_UNMODIFIED ||
+		delta->status == GIT_DELTA_IGNORED ||
+		(delta->status == GIT_DELTA_UNTRACKED &&
+		 (opts_flags & GIT_DIFF_INCLUDE_UNTRACKED_CONTENT) == 0))
 		return 0;
 
-	git_buf_clear(pi->buf);
-	git_buf_printf(
-		pi->buf, "Binary files %s%s and %s%s differ\n",
-		oldpfx, oldpath, newpfx, newpath);
-	if (git_buf_oom(pi->buf))
+	if (git_diff_delta__format_file_header(
+			pi->buf, delta, oldpfx, newpfx, pi->oid_strlen) < 0)
 		return -1;
 
-	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_BINARY,
+	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
 			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
 		return callback_error();
 

tests-clar/diff/patch.c

@@ -128,8 +128,10 @@ void test_diff_patch__to_string(void)
 
 	cl_assert_equal_s(expected, text);
 
-	cl_assert_equal_sz(31, git_diff_patch_size(patch, 0));
-	cl_assert_equal_sz(31, git_diff_patch_size(patch, 1));
+	cl_assert_equal_sz(31, git_diff_patch_size(patch, 0, 0, 0));
+	cl_assert_equal_sz(31, git_diff_patch_size(patch, 1, 0, 0));
+	cl_assert_equal_sz(31 + 16, git_diff_patch_size(patch, 1, 1, 0));
+	cl_assert_equal_sz(strlen(expected), git_diff_patch_size(patch, 1, 1, 1));
 
 	git__free(text);
 	git_diff_patch_free(patch);
@@ -411,8 +413,7 @@ void test_diff_patch__hunks_have_correct_line_numbers(void)
 
 static void check_single_patch_stats(
 	git_repository *repo, size_t hunks,
-	size_t adds, size_t dels, size_t ctxt,
-	size_t size_with_context, size_t size_without_context,
+	size_t adds, size_t dels, size_t ctxt, size_t *sizes,
 	const char *expected)
 {
 	git_diff_list *diff;
@@ -441,14 +442,19 @@ static void check_single_patch_stats(
 		cl_git_pass(git_diff_patch_to_str(&text, patch));
 		cl_assert_equal_s(expected, text);
 		git__free(text);
-	}
 
-	if (size_with_context)
-		cl_assert_equal_sz(
-			size_with_context, git_diff_patch_size(patch, 1));
-	if (size_without_context)
 		cl_assert_equal_sz(
-			size_without_context, git_diff_patch_size(patch, 0));
+			strlen(expected), git_diff_patch_size(patch, 1, 1, 1));
+	}
+
+	if (sizes) {
+		if (sizes[0])
+			cl_assert_equal_sz(sizes[0], git_diff_patch_size(patch, 0, 0, 0));
+		if (sizes[1])
+			cl_assert_equal_sz(sizes[1], git_diff_patch_size(patch, 1, 0, 0));
+		if (sizes[2])
+			cl_assert_equal_sz(sizes[2], git_diff_patch_size(patch, 1, 1, 0));
+	}
 
 	/* walk lines in hunk with basic sanity checks */
 	for (; hunks > 0; --hunks) {
@@ -492,6 +498,23 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	git_buf content = GIT_BUF_INIT;
 	const char *end;
 	git_index *index;
+	const char *expected =
+		/* below is pasted output of 'git diff' with fn context removed */
+		"diff --git a/songof7cities.txt b/songof7cities.txt\n"
+		"index 378a7d9..3d0154e 100644\n"
+		"--- a/songof7cities.txt\n"
+		"+++ b/songof7cities.txt\n"
+		"@@ -42,7 +42,7 @@ With peoples undefeated of the dark, enduring blood.\n"
+		" \n"
+		" To the sound of trumpets shall their seed restore my Cities\n"
+		" Wealthy and well-weaponed, that once more may I behold\n"
+		"-All the world go softly when it walks before my Cities,\n"
+		"+#All the world go softly when it walks before my Cities,\n"
+		" And the horses and the chariots fleeing from them as of old!\n"
+		" \n"
+		"   -- Rudyard Kipling\n"
+		"\\ No newline at end of file\n";
+	size_t expected_sizes[3] = { 115, 119 + 115 + 114, 119 + 115 + 114 + 71 };
 
 	g_repo = cl_git_sandbox_init("renames");
 
@@ -506,14 +529,14 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	git_buf_consume(&content, end);
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 1, 0, 1, 3, 0, 0, NULL);
+	check_single_patch_stats(g_repo, 1, 0, 1, 3, NULL, NULL);
 
 	/* remove trailing whitespace */
 
 	git_buf_rtrim(&content);
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 2, 1, 2, 6, 0, 0, NULL);
+	check_single_patch_stats(g_repo, 2, 1, 2, 6, NULL, NULL);
 
 	/* add trailing whitespace */
 
@@ -525,7 +548,7 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	cl_git_pass(git_buf_putc(&content, '\n'));
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
-	check_single_patch_stats(g_repo, 1, 1, 1, 3, 0, 0, NULL);
+	check_single_patch_stats(g_repo, 1, 1, 1, 3, NULL, NULL);
 
 	/* no trailing whitespace as context line */
 
@@ -548,22 +571,7 @@ void test_diff_patch__line_counts_with_eofnl(void)
 	cl_git_rewritefile("renames/songof7cities.txt", content.ptr);
 
 	check_single_patch_stats(
-		g_repo, 1, 1, 1, 6, 349, 115,
-		/* below is pasted output of 'git diff' with fn context removed */
-		"diff --git a/songof7cities.txt b/songof7cities.txt\n"
-		"index 378a7d9..3d0154e 100644\n"
-		"--- a/songof7cities.txt\n"
-		"+++ b/songof7cities.txt\n"
-		"@@ -42,7 +42,7 @@ With peoples undefeated of the dark, enduring blood.\n"
-		" \n"
-		" To the sound of trumpets shall their seed restore my Cities\n"
-		" Wealthy and well-weaponed, that once more may I behold\n"
-		"-All the world go softly when it walks before my Cities,\n"
-		"+#All the world go softly when it walks before my Cities,\n"
-		" And the horses and the chariots fleeing from them as of old!\n"
-		" \n"
-		"   -- Rudyard Kipling\n"
-		"\\ No newline at end of file\n");
+		g_repo, 1, 1, 1, 6, expected_sizes, expected);
 
 	git_buf_free(&content);
 	git_config_free(cfg);