Add text object to cover lines with same indentation level

By default it is mapped to i<Tab> and a<Tab> however there
is currently no difference between the inner and regular
version.

config.def.h

@@ -123,6 +123,8 @@ static const KeyBinding bindings_textobjects[] = {
 	{ "ie",                 ACTION(TEXT_OBJECT_ENTIRE_INNER)            },
 	{ "if",                 ACTION(TEXT_OBJECT_FUNCTION_INNER)          },
 	{ "il",                 ACTION(TEXT_OBJECT_LINE_INNER)              },
+	{ "i<Tab>",             ACTION(TEXT_OBJECT_INDENTATION)             },
+	{ "a<Tab>",             ACTION(TEXT_OBJECT_INDENTATION)             },
 	{ "gn",                 ACTION(TEXT_OBJECT_SEARCH_FORWARD)          },
 	{ "gN",                 ACTION(TEXT_OBJECT_SEARCH_BACKWARD)         },
 	{ 0 /* empty last element, array terminator */                      },

main.c

@@ -272,6 +272,7 @@ enum {
 	VIS_ACTION_TEXT_OBJECT_FUNCTION_INNER,
 	VIS_ACTION_TEXT_OBJECT_LINE_OUTER,
 	VIS_ACTION_TEXT_OBJECT_LINE_INNER,
+	VIS_ACTION_TEXT_OBJECT_INDENTATION,
 	VIS_ACTION_TEXT_OBJECT_SEARCH_FORWARD,
 	VIS_ACTION_TEXT_OBJECT_SEARCH_BACKWARD,
 	VIS_ACTION_MOTION_CHARWISE,
@@ -1060,6 +1061,11 @@ static const KeyAction vis_action[] = {
 		"The whole line, excluding leading and trailing whitespace",
 		textobj, { .i = VIS_TEXTOBJECT_INNER_LINE }
 	},
+	[VIS_ACTION_TEXT_OBJECT_INDENTATION] = {
+		"text-object-indentation",
+		"All adjacent lines with the same indentation level as the current one",
+		textobj, { .i = VIS_TEXTOBJECT_INDENTATION }
+	},
 	[VIS_ACTION_TEXT_OBJECT_SEARCH_FORWARD] = {
 		"text-object-search-forward",
 		"The next search match in forward direction",

text-objects.c

@@ -359,6 +359,62 @@ Filerange text_object_search_backward(Text *txt, size_t pos, Regex *regex) {
 	return text_range_empty();
 }
 
+Filerange text_object_indentation(Text *txt, size_t pos) {
+	char c;
+	size_t bol = text_line_begin(txt, pos);
+	size_t sol = text_line_start(txt, bol);
+	size_t start = bol;
+	size_t end = text_line_next(txt, bol);
+	size_t line_indent = sol - bol;
+	bool line_empty = text_byte_get(txt, bol, &c) && (c == '\r' || c == '\n');
+
+	char *buf = text_bytes_alloc0(txt, bol, line_indent);
+	char *tmp = malloc(line_indent);
+
+	if (!buf || !tmp) {
+		free(buf);
+		free(tmp);
+		return text_range_empty();
+	}
+
+	while ((bol = text_line_begin(txt, text_line_prev(txt, start))) != start) {
+		sol = text_line_start(txt, bol);
+		size_t indent = sol - bol;
+		if (indent < line_indent)
+			break;
+		bool empty = text_byte_get(txt, bol, &c) && (c == '\r' || c == '\n');
+		if (line_empty && !empty)
+			break;
+		if (line_indent == 0 && empty)
+			break;
+		text_bytes_get(txt, bol, line_indent, tmp);
+		if (memcmp(buf, tmp, line_indent))
+			break;
+		start = bol;
+	}
+
+	do {
+		bol = end;
+		sol = text_line_start(txt, bol);
+		size_t indent = sol - bol;
+		if (indent < line_indent)
+			break;
+		bool empty = text_byte_get(txt, bol, &c) && (c == '\r' || c == '\n');
+		if (line_empty && !empty)
+			break;
+		if (line_indent == 0 && empty)
+			break;
+		text_bytes_get(txt, bol, line_indent, tmp);
+		if (memcmp(buf, tmp, line_indent))
+			break;
+		end = text_line_next(txt, bol);
+	} while (bol != end);
+
+	free(buf);
+	free(tmp);
+	return text_range_new(start, end);
+}
+
 Filerange text_range_linewise(Text *txt, Filerange *rin) {
 	Filerange rout = *rin;
 	rout.start = text_line_begin(txt, rin->start);

text-objects.h

@@ -51,6 +51,8 @@ Filerange text_object_filename(Text*, size_t pos);
 /* match a search term in either forward or backward direction */
 Filerange text_object_search_forward(Text*, size_t pos, Regex*);
 Filerange text_object_search_backward(Text*, size_t pos, Regex*);
+/* match all lines with same indendation level than the current one */
+Filerange text_object_indentation(Text*, size_t pos);
 
 /* extend a range to cover whole lines */
 Filerange text_range_linewise(Text*, Filerange*);

vis-text-objects.c

@@ -44,6 +44,7 @@ const TextObject vis_textobjects[] = {
 	[VIS_TEXTOBJECT_INNER_FUNCTION]       = { .txt = text_object_function_inner,               },
 	[VIS_TEXTOBJECT_OUTER_LINE]           = { .txt = text_object_line,                         },
 	[VIS_TEXTOBJECT_INNER_LINE]           = { .txt = text_object_line_inner,                   },
+	[VIS_TEXTOBJECT_INDENTATION]          = { .txt = text_object_indentation,                  },
 	[VIS_TEXTOBJECT_SEARCH_FORWARD]       = { .vis = search_forward,             .type = SPLIT },
 	[VIS_TEXTOBJECT_SEARCH_BACKWARD]      = { .vis = search_backward,            .type = SPLIT },
 };

vis.h

@@ -300,6 +300,7 @@ enum VisTextObject {
 	VIS_TEXTOBJECT_INNER_FUNCTION,
 	VIS_TEXTOBJECT_OUTER_LINE,
 	VIS_TEXTOBJECT_INNER_LINE,
+	VIS_TEXTOBJECT_INDENTATION,
 	VIS_TEXTOBJECT_SEARCH_FORWARD,
 	VIS_TEXTOBJECT_SEARCH_BACKWARD,
 	VIS_TEXTOBJECT_INVALID,