Restrict cursor navigation to actionable linesgh-255-actionable-lines

This updates the status, grep, tree and help views to only allow the
cursor to move to actionable lines.

Fixes #255

7 files changed, 84 insertions, 33 deletions

diff --git a/include/tig/view.h b/include/tig/view.h
index 64876869..d02123ed 100644
--- a/include/tig/view.h
+++ b/include/tig/view.h
@@ -31,6 +31,7 @@ struct line {
 	unsigned int dirty:1;
 	unsigned int cleareol:1;
 	unsigned int wrapped:1;
+	unsigned int noaction:1;
 
 	unsigned int user_flags:6;
 	void *data;		/* User data */
@@ -295,14 +296,14 @@ void update_view_title(struct view *view);
  * Line utilities.
  */
 
-struct line *add_line_at(struct view *view, unsigned long pos, const void *data, enum line_type type, size_t data_size, bool custom);
+struct line *add_line_at(struct view *view, unsigned long pos, const void *data, enum line_type type, size_t data_size, bool custom, bool noaction);
 struct line *add_line(struct view *view, const void *data, enum line_type type, size_t data_size, bool custom);
 struct line *add_line_alloc_(struct view *view, void **ptr, enum line_type type, size_t data_size, bool custom);
 
 #define add_line_alloc(view, data_ptr, type, extra_size, custom) \
 	add_line_alloc_(view, (void **) data_ptr, type, sizeof(**data_ptr) + extra_size, custom)
 
-struct line *add_line_nodata(struct view *view, enum line_type type);
+struct line *add_line_nodata(struct view *view, enum line_type type, bool noaction);
 struct line *add_line_text(struct view *view, const char *text, enum line_type type);
 struct line * PRINTF_LIKE(3, 4) add_line_format(struct view *view, enum line_type type, const char *fmt, ...);
 
diff --git a/src/grep.c b/src/grep.c
index bdc0038b..47a80e0c 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -123,6 +123,9 @@ grep_open(struct view *view, enum open_flags flags)
 		opt_cmdline_argv = NULL;
 	}
 
+	if (!view->pos.lineno) //!check_position(&view->pos))
+		view->pos.lineno = 1;
+
 	if (!argv_append_array(&argv, grep_args) ||
 	    !argv_append_array(&argv, grep_argv))
 		return FALSE;
@@ -204,7 +207,7 @@ grep_read(struct view *view, char *line)
 	}
 
 	if (!strcmp(line, "--"))
-		return add_line_nodata(view, LINE_DELIMITER) != NULL;
+		return add_line_nodata(view, LINE_DELIMITER, TRUE) != NULL;
 
 	lineno = io_memchr(&view->io, line, 0);
 	text = io_memchr(&view->io, lineno + 1, 0);
@@ -217,10 +220,17 @@ grep_read(struct view *view, char *line)
 	textlen = strlen(text);
 
 	file = get_path(line);
-	if (!file ||
-	    (file != state->last_file && !add_line_text(view, file, LINE_FILENAME)))
+	if (!file)
 		return FALSE;
 
+	if (file != state->last_file) {
+		struct line *filename = add_line_text(view, file, LINE_FILENAME);
+
+		if (!filename)
+			return FALSE;
+		filename->noaction = TRUE;
+	}
+
 	if (!add_line_alloc(view, &grep, LINE_DEFAULT, textlen, FALSE))
 		return FALSE;
 
diff --git a/src/help.c b/src/help.c
index d3509d86..1f4362e5 100644
--- a/src/help.c
+++ b/src/help.c
@@ -132,17 +132,19 @@ struct help_request_iterator {
 	const char *group;
 };
 
-static bool
+static struct line *
 add_help_line(struct view *view, struct help **help_ptr, struct keymap *keymap, enum line_type type)
 {
 	struct help *help;
+	struct line *line = add_line_alloc(view, &help, type, 0, FALSE);
 
-	if (!add_line_alloc(view, &help, type, 0, FALSE))
-		return FALSE;
+	if (!line)
+		return NULL;
 	help->keymap = keymap;
 	if (help_ptr)
 		*help_ptr = help;
-	return TRUE;
+	line->noaction = !keymap;
+	return line;
 }
 
 static bool
@@ -229,17 +231,21 @@ help_open(struct view *view, enum open_flags flags)
 {
 	struct keymap *keymap;
 	struct help *help;
+	struct line *line;
 
 	reset_view(view);
 
-	if (!add_help_line(view, &help, NULL, LINE_DEFAULT))
+	if (!(line = add_help_line(view, &help, NULL, LINE_DEFAULT)))
 		return FALSE;
 	help->data.text = "Quick reference for tig keybindings:";
 
-	if (!add_help_line(view, &help, NULL, LINE_DEFAULT))
+	if (!(line = add_help_line(view, &help, NULL, LINE_DEFAULT)))
 		return FALSE;
 	help->data.text = "";
 
+	if (!check_position(&view->prev_pos))
+		view->prev_pos.lineno = 2;
+
 	for (keymap = get_keymaps(); keymap; keymap = keymap->next) {
 		struct help_request_iterator iterator = { view, keymap, TRUE };
 
diff --git a/src/stage.c b/src/stage.c
index fd646509..6d673546 100644
--- a/src/stage.c
+++ b/src/stage.c
@@ -263,13 +263,13 @@ stage_insert_chunk(struct view *view, struct chunk_header *header,
 	if (!to)
 		return from;
 
-	if (!add_line_at(view, after_lineno++, buf, LINE_DIFF_CHUNK, strlen(buf) + 1, FALSE))
+	if (!add_line_at(view, after_lineno++, buf, LINE_DIFF_CHUNK, strlen(buf) + 1, FALSE, FALSE))
 		return NULL;
 
 	while (from_lineno < to_lineno) {
 		struct line *line = &view->line[from_lineno++];
 
-		if (!add_line_at(view, after_lineno++, line->data, line->type, strlen(line->data) + 1, FALSE))
+		if (!add_line_at(view, after_lineno++, line->data, line->type, strlen(line->data) + 1, FALSE, FALSE))
 			return FALSE;
 	}
 
diff --git a/src/status.c b/src/status.c
index 4e345031..c1f9eae6 100644
--- a/src/status.c
+++ b/src/status.c
@@ -77,12 +77,12 @@ status_run(struct view *view, const char *argv[], char status, enum line_type ty
 	struct status *unmerged = NULL;
 	char *buf;
 	struct io io;
+	struct line *section_line;
 
-	if (!io_run(&io, IO_RD, repo.cdup, opt_env, argv))
+	if (!io_run(&io, IO_RD, repo.cdup, opt_env, argv) ||
+	    !(section_line = add_line_nodata(view, type, FALSE)))
 		return FALSE;
 
-	add_line_nodata(view, type);
-
 	while ((buf = io_get(&io, 0, TRUE))) {
 		struct status *file = unmerged;
 
@@ -140,8 +140,10 @@ error_out:
 		return FALSE;
 	}
 
-	if (!view->line[view->lines - 1].data)
-		add_line_nodata(view, LINE_STAT_NONE);
+	if (!view->line[view->lines - 1].data) {
+		section_line->noaction = TRUE;
+		add_line_nodata(view, LINE_STAT_NONE, TRUE);
+	}
 
 	io_done(&io);
 	return TRUE;
@@ -255,8 +257,10 @@ status_open(struct view *view, enum open_flags flags)
 	}
 
 	reset_view(view);
+	if (!check_position(&view->prev_pos))
+		view->prev_pos.lineno = 1;
 
-	add_line_nodata(view, LINE_STAT_HEAD);
+	add_line_nodata(view, LINE_STAT_HEAD, TRUE);
 	status_update_onbranch();
 
 	io_run_bg(update_index_argv);
diff --git a/src/tree.c b/src/tree.c
index cac154fc..80634e70 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -147,6 +147,8 @@ tree_entry(struct view *view, enum line_type type, const char *path,
 	if (id)
 		string_copy_rev(entry->id, id);
 	entry->size = size;
+	if (type == LINE_TREE_HEAD)
+		line->noaction = TRUE;
 
 	return line;
 }
diff --git a/src/view.c b/src/view.c
index fac1f003..fda2a234 100644
--- a/src/view.c
+++ b/src/view.c
@@ -32,7 +32,7 @@ goto_view_line(struct view *view, unsigned long offset, unsigned long lineno)
 	if (offset > lineno || offset + view->height <= lineno) {
 		unsigned long half = view->height / 2;
 
-		if (lineno > half)
+		if (lineno > half && view->lines <= view->height)
 			offset = lineno - half;
 		else
 			offset = 0;
@@ -167,6 +167,7 @@ scroll_view(struct view *view, enum request request)
 void
 move_view(struct view *view, enum request request)
 {
+	struct position pos = view->pos;
 	int scroll_steps = 0;
 	int steps;
 
@@ -203,18 +204,33 @@ move_view(struct view *view, enum request request)
 		die("request %d not handled in switch", request);
 	}
 
-	if (steps <= 0 && view->pos.lineno == 0) {
-		report("Cannot move beyond the first line");
-		return;
+	while (TRUE) {
+		if (steps <= 0 && pos.lineno == 0) {
+			if (pos.lineno != view->pos.lineno)
+				report("No selectable line above this line");
+			else
+				report("Cannot move beyond the first line");
+			return;
 
-	} else if (steps >= 0 && view->pos.lineno + 1 >= view->lines) {
-		report("Cannot move beyond the last line");
-		return;
+		} else if (steps >= 0 && pos.lineno + 1 >= view->lines) {
+			if (pos.lineno != view->pos.lineno)
+				report("No selectable line below this line");
+			else
+				report("Cannot move beyond the last line");
+			return;
+		}
+
+		/* Move the current line */
+		pos.lineno += steps;
+		assert(0 <= pos.lineno && pos.lineno < view->lines);
+
+		if (!view->line[pos.lineno].noaction)
+			break;
+		steps = steps > 0 ? 1 : -1;
 	}
 
-	/* Move the current line */
-	view->pos.lineno += steps;
-	assert(0 <= view->pos.lineno && view->pos.lineno < view->lines);
+	steps = pos.lineno - view->pos.lineno;
+	view->pos = pos;
 
 	/* Check whether the view needs to be scrolled */
 	if (view->pos.lineno < view->pos.offset ||
@@ -477,6 +493,13 @@ restore_view_position(struct view *view)
 	    view_is_displayed(view))
 		werase(view->win);
 
+	if (view->line[view->pos.lineno].noaction) {
+		if (view->prev_pos.lineno < view->pos.lineno)
+			move_view(view, REQ_MOVE_UP);
+		else
+			move_view(view, REQ_MOVE_DOWN);
+	}
+
 	view->pos.col = view->prev_pos.col;
 	clear_position(&view->prev_pos);
 
@@ -849,7 +872,7 @@ find_line_by_type(struct view *view, struct line *line, enum line_type type, int
 DEFINE_ALLOCATOR(realloc_lines, struct line, 256)
 
 struct line *
-add_line_at(struct view *view, unsigned long pos, const void *data, enum line_type type, size_t data_size, bool custom)
+add_line_at(struct view *view, unsigned long pos, const void *data, enum line_type type, size_t data_size, bool custom, bool noaction)
 {
 	struct line *line;
 	unsigned long lineno;
@@ -887,6 +910,7 @@ add_line_at(struct view *view, unsigned long pos, const void *data, enum line_ty
 	line->type = type;
 	line->data = (void *) data;
 	line->dirty = 1;
+	line->noaction = noaction;
 
 	if (custom)
 		view->custom_lines++;
@@ -899,7 +923,7 @@ add_line_at(struct view *view, unsigned long pos, const void *data, enum line_ty
 struct line *
 add_line(struct view *view, const void *data, enum line_type type, size_t data_size, bool custom)
 {
-	return add_line_at(view, view->lines, data, type, data_size, custom);
+	return add_line_at(view, view->lines, data, type, data_size, custom, 0);
 }
 
 struct line *
@@ -913,9 +937,13 @@ add_line_alloc_(struct view *view, void **ptr, enum line_type type, size_t data_
 }
 
 struct line *
-add_line_nodata(struct view *view, enum line_type type)
+add_line_nodata(struct view *view, enum line_type type, bool noaction)
 {
-	return add_line(view, NULL, type, 0, FALSE);
+	struct line *line = add_line(view, NULL, type, 0, FALSE);
+
+	if (line)
+		line->noaction = !!noaction;
+	return line;
 }
 
 struct line *