Unify jumping to line IDs using a git-rev-parse-able expression

This allows to create keybindings to go to the 2nd parent and jumping to
a commit by branch name.

NEWS.adoc

@@ -34,6 +34,8 @@ Improvements:
  - Compact relative date display mode. (GH #331)
  - Add date column option controlling whether to show local date.
  - Move to parent commit in the main view. (GH #388)
+ - Add `:goto <rev>` prompt command to go to a `git-rev-parse`d revision, e.g.
+   `:goto some/branch` or `:goto %(commit)^2`.
  - Respect the XDG standard for configuration files. (GH #513)
  - Support for custom `strftime(3)` date formats, e.g.:
 

doc/manual.adoc

@@ -468,6 +468,10 @@ Prompt
 |:<x>			|Execute the corresponding key binding, e.g. `:q`.
 |:!<command>		|Execute a system command in a pager, e.g. `:!git log -p`.
 |:<action>		|Execute a Tig command, e.g. `:edit`.
+|:goto <rev>		|Jump to a specific revision, e.g. `:goto %(commit)^2`
+			 to goto the current commit's 2nd parent or
+			 `:goto some/branch` to goto the commit denoting the
+			 branch `some/branch`.
 |:save-display <file>	|Save current display to `<file>`.
 |:save-options <file>	|Save current options to `<file>`.
 |:script <file>		|Execute commands from `<file>`.

include/tig/io.h

@@ -87,8 +87,8 @@ ssize_t io_read(struct io *io, void *buf, size_t bufsize);
 bool io_get(struct io *io, struct buffer *buf, int c, bool can_read);
 bool io_write(struct io *io, const void *buf, size_t bufsize);
 bool io_printf(struct io *io, const char *fmt, ...) PRINTF_LIKE(2, 3);
-bool io_read_buf(struct io *io, char buf[], size_t bufsize);
-bool io_run_buf(const char **argv, char buf[], size_t bufsize);
+bool io_read_buf(struct io *io, char buf[], size_t bufsize, bool allow_empty);
+bool io_run_buf(const char **argv, char buf[], size_t bufsize, bool allow_empty);
 enum status_code io_load(struct io *io, const char *separators,
 	    io_read_fn read_property, void *data);
 enum status_code io_load_span(struct io *io, const char *separators,

include/tig/view.h

@@ -258,6 +258,7 @@ void select_view_line(struct view *view, unsigned long lineno);
 void do_scroll_view(struct view *view, int lines);
 void scroll_view(struct view *view, enum request request);
 void move_view(struct view *view, enum request request);
+void goto_id(struct view *view, const char *expression, bool from_start, bool save_search);
 
 /*
  * View history

src/blob.c

@@ -71,7 +71,7 @@ blob_open(struct view *view, enum open_flags flags)
 		};
 
 		if (!string_format(blob_spec, "%s:%s", commit, view->env->file) ||
-		    !io_run_buf(rev_parse_argv, view->env->blob, sizeof(view->env->blob))) {
+		    !io_run_buf(rev_parse_argv, view->env->blob, sizeof(view->env->blob), false)) {
 			report("Failed to resolve blob from file name");
 			return false;
 		}

src/io.c

@@ -109,7 +109,7 @@ get_path_encoding(const char *path, struct encoding *default_encoding)
 
 	/* <path>: encoding: <encoding> */
 
-	if (!*path || !io_run_buf(check_attr_argv, buf, sizeof(buf))
+	if (!*path || !io_run_buf(check_attr_argv, buf, sizeof(buf), false)
 	    || !(encoding = strstr(buf, ENCODING_SEP)))
 		return default_encoding;
 
@@ -121,7 +121,7 @@ get_path_encoding(const char *path, struct encoding *default_encoding)
 			"file", "-I", "--", path, NULL
 		};
 
-		if (!*path || !io_run_buf(file_argv, buf, sizeof(buf))
+		if (!*path || !io_run_buf(file_argv, buf, sizeof(buf), false)
 		    || !(encoding = strstr(buf, CHARSET_SEP)))
 			return default_encoding;
 
@@ -532,7 +532,7 @@ io_printf(struct io *io, const char *fmt, ...)
 }
 
 bool
-io_read_buf(struct io *io, char buf[], size_t bufsize)
+io_read_buf(struct io *io, char buf[], size_t bufsize, bool allow_empty)
 {
 	struct buffer result = {0};
 
@@ -541,15 +541,15 @@ io_read_buf(struct io *io, char buf[], size_t bufsize)
 		string_ncopy_do(buf, bufsize, result.data, strlen(result.data));
 	}
 
-	return io_done(io) && result.data;
+	return io_done(io) && (result.data || allow_empty);
 }
 
 bool
-io_run_buf(const char **argv, char buf[], size_t bufsize)
+io_run_buf(const char **argv, char buf[], size_t bufsize, bool allow_empty)
 {
 	struct io io;
 
-	return io_run(&io, IO_RD, NULL, NULL, argv) && io_read_buf(&io, buf, bufsize);
+	return io_run(&io, IO_RD, NULL, NULL, argv) && io_read_buf(&io, buf, bufsize, allow_empty);
 }
 
 bool

src/main.c

@@ -500,43 +500,6 @@ main_read(struct view *view, struct buffer *buf, bool force_stop)
 	return true;
 }
 
-static void
-main_move_to_parent(struct view *view)
-{
-	struct line *line = &view->line[view->pos.lineno];
-	struct commit *commit = line->data;
-
-	/* Handle staged and unstaged commit lines. */
-	if (string_rev_is_null(commit->id)) {
-		line++;
-
-	} else {
-		const char *rev_list_parents_argv[] = {
-			"git", "log", "--no-color", "-n1", "--pretty=format:%P",
-				commit->id, NULL
-		};
-		char parents[SIZEOF_STR] = "";
-
-		if (!io_run_buf(rev_list_parents_argv, parents, sizeof(parents))) {
-			report("Failed to read commit parent(s)");
-			return;
-		}
-
-		/* Find a commit line matching the first parent commit ID. */
-		for (line++; view_has_line(view, line); line++) {
-			commit = line->data;
-
-			if (!strncasecmp(commit->id, parents, strlen(commit->id)))
-				break;
-		}
-	}
-
-	if (view_has_line(view, line)) {
-		select_view_line(view, line - view->line);
-		report_clear();
-	}
-}
-
 enum request
 main_request(struct view *view, enum request request, struct line *line)
 {
@@ -570,7 +533,7 @@ main_request(struct view *view, enum request request, struct line *line)
 		break;
 
 	case REQ_PARENT:
-		main_move_to_parent(view);
+		goto_id(view, "%(commit)^", true, false);
 		break;
 
 	default:

src/prompt.c

@@ -234,6 +234,7 @@ readline_action_generator(const char *text, int state)
 		"bind",
 		"set",
 		"toggle",
+		"goto",
 		"save-display",
 		"save-options",
 		"exec",
@@ -753,28 +754,7 @@ run_prompt_command(struct view *view, const char *argv[])
 			report("Unable to parse '%s' as a line number", cmd);
 		}
 	} else if (iscommit(cmd)) {
-		int lineno;
-
-		if (!(view->ops->column_bits & view_column_bit(ID))) {
-			report("Jumping to commits is not supported by the %s view", view->name);
-			return REQ_NONE;
-		}
-
-		for (lineno = 0; lineno < view->lines; lineno++) {
-			struct view_column_data column_data = {0};
-			struct line *line = &view->line[lineno];
-
-			if (view->ops->get_column_data(view, line, &column_data) &&
-			    column_data.id &&
-			    !strncasecmp(column_data.id, cmd, cmdlen)) {
-				string_ncopy(view->env->search, cmd, cmdlen);
-				select_view_line(view, lineno);
-				report_clear();
-				return REQ_NONE;
-			}
-		}
-
-		report("Unable to find commit '%s'", view->env->search);
+		goto_id(view, cmd, true, true);
 		return REQ_NONE;
 
 	} else if (cmdlen > 1 && (cmd[0] == '/' || cmd[0] == '?')) {
@@ -812,6 +792,13 @@ run_prompt_command(struct view *view, const char *argv[])
 			open_pager_view(view, OPEN_PREPARED | OPEN_WITH_STDERR);
 		}
 
+	} else if (!strcmp(cmd, "goto")) {
+		if (!argv[1] || !strlen(argv[1]))
+			report("goto requires an argument");
+		else
+			goto_id(view, argv[1], true, true);
+		return REQ_NONE;
+
 	} else if (!strcmp(cmd, "save-display")) {
 		const char *path = argv[1] ? argv[1] : "tig-display.txt";
 

src/status.c

@@ -299,7 +299,7 @@ status_update_onbranch(void)
 			struct io io;
 
 			if (io_open(&io, "%s/%s", repo.git_dir, paths[i][1]) &&
-			    io_read_buf(&io, buf, sizeof(buf))) {
+			    io_read_buf(&io, buf, sizeof(buf), false)) {
 				head = buf;
 				if (!prefixcmp(head, "refs/heads/"))
 					head += STRING_SIZE("refs/heads/");

src/view.c

@@ -288,6 +288,61 @@ select_view_line(struct view *view, unsigned long lineno)
 	}
 }
 
+void
+goto_id(struct view *view, const char *expr, bool from_start, bool save_search)
+{
+	struct view_column_data column_data = {0};
+	char id[SIZEOF_STR] = "";
+	size_t idlen;
+	struct line *line = &view->line[view->pos.lineno];
+
+	if (!(view->ops->column_bits & view_column_bit(ID))) {
+		report("Jumping to ID is not supported by the %s view", view->name);
+		return;
+	} else {
+		char *rev = argv_format_arg(view->env, expr);
+		const char *rev_parse_argv[] = {
+			"git", "rev-parse", "--revs-only", rev, NULL
+		};
+		bool ok = rev && io_run_buf(rev_parse_argv, id, sizeof(id), true);
+
+		free(rev);
+		if (!ok) {
+			report("Failed to parse expression '%s'", expr);
+			return;
+		}
+	}
+
+	if (!id[0]) {
+		if (view->ops->get_column_data(view, line, &column_data)
+		    && column_data.id && string_rev_is_null(column_data.id)) {
+			select_view_line(view, view->pos.lineno + 1);
+			report_clear();
+		} else {
+			report("Expression '%s' is not a meaningful revision", expr);
+		}
+		return;
+	}
+
+	line = from_start ? view->line : &view->line[view->pos.lineno];
+
+	for (idlen = strlen(id); view_has_line(view, line); line++) {
+		struct view_column_data column_data = {0};
+
+		if (view->ops->get_column_data(view, line, &column_data) &&
+		    column_data.id &&
+		    !strncasecmp(column_data.id, id, idlen)) {
+			if (save_search)
+				string_ncopy(view->env->search, id, idlen);
+			select_view_line(view, line - view->line);
+			report_clear();
+			return;
+		}
+	}
+
+	report("Unable to find commit '%s'", view->env->search);
+}
+
 /*
  * View history
  */

test/main/move-to-parent-test → test/main/goto-test

@@ -7,17 +7,18 @@
 export LINES=10
 
 steps '
+	:3
+	:save-display unstaged-changes.screen
+	:parent
+	:save-display commit-3.screen
+	:goto conflict-branch
 	:save-display commit-1.screen
 	:parent
 	:save-display commit-2.screen
 	:parent
 	:save-display commit-5.screen
 	:parent
 	:save-display commit-5-still.screen
-	:3
-	:save-display unstaged-changes.screen
-	:parent
-	:save-display commit-3.screen
 '
 
 tigrc <<EOF