Merge pull request #96 from olin/brushmode-mouse-segfault

Fix brush mode segfaults

src/cursor.c

@@ -25,12 +25,21 @@ Cursor *cursor_newyx(int y, int x) {
 }
 
 /* Make a copy of an existing cursor.
- *
  */
 Cursor *cursor_copy(Cursor *original) {
   return cursor_newyx(original->y, original->x);
 }
 
+void cursor_free(Cursor *cursor) {
+  free(cursor);
+}
+
+/* Check if a cursor is contained in the view.
+ */
+bool cursor_isin_view(Cursor *cursor, View *view) {
+  return view_isin(view, cursor->y, cursor->x);
+}
+
 void cursor_move_up(Cursor *cursor, View *view) {
   if (cursor->y == 0) {
     view_move_up(view);
@@ -79,6 +88,12 @@ int cursor_y_to_canvas(Cursor *cursor) {
   return cursor->y + 1;
 }
 
+/* Attempt to move the cursor given an arrow key input.
+ *
+ * If the move would push the cursor beyond the current view (the cursor is
+ * at an edge of the screen) the view will be shifted if there is more canvas,
+ * otherwise it is a no-op.
+ */
 void cursor_key_to_move(int arrow, Cursor *cursor, View *view) {
   switch (arrow) {
     case KEY_LEFT:
@@ -109,7 +124,3 @@ int cursor_opposite_dir(int arrow) {
   }
   return -1;
 }
-
-void cursor_free(Cursor *cursor) {
-  free(cursor);
-}

src/cursor.h

@@ -20,6 +20,8 @@ Cursor *cursor_newyx(int y, int x);
 Cursor *cursor_copy(Cursor *original);
 void cursor_free(Cursor *cursor);
 
+bool cursor_isin_view(Cursor *cursor, View *view);
+
 void cursor_move_up(Cursor *cursor, View *view);
 void cursor_move_down(Cursor *cursor, View *view);
 void cursor_move_left(Cursor *cursor, View *view);

src/fe_modes.c

@@ -47,10 +47,13 @@ typedef struct {
 } mode_brush_config_t;
 
 mode_brush_config_t mode_brush_config = {
-    .pattern = 'B', .state = PAINT_OFF,
+    .pattern = 'B',
+    .state = PAINT_OFF,
 };
 
-typedef struct { Cursor *last_dir_change; } mode_insert_config_t;
+typedef struct {
+  Cursor *last_dir_change;
+} mode_insert_config_t;
 
 mode_insert_config_t mode_insert_config = {NULL};
 
@@ -497,10 +500,14 @@ int mode_brush(reason_t reason, State *state) {
     } else if (state->mevent_in->bstate & BUTTON1_RELEASED) {
       mode_cfg->state = PAINT_OFF;
     }
-    // only update cursor position on mouse move if we're painting
+    // only update cursor position on mouse move if we're painting and in view
     if (mode_cfg->state == PAINT_ON) {
-      state->cursor->x = state->mevent_in->x - 1;
-      state->cursor->y = state->mevent_in->y - 1;
+      const int x = state->mevent_in->x - 1;
+      const int y = state->mevent_in->y - 1;
+      if (view_isin(state->view, y, x)) {
+        state->cursor->x = x;
+        state->cursor->y = y;
+      }
     }
   } else if (reason == NEW_KEY) {
     if ((state->ch_in == KEY_LEFT) || (state->ch_in == KEY_RIGHT) ||

src/frontend.c

@@ -373,7 +373,7 @@ int main(int argc, char *argv[]) {
   mmask |= REPORT_MOUSE_POSITION;
 #endif
   mmask_t return_mask = mousemask(mmask, NULL);
-  logd("Returned mouse mask: %li\n", return_mask);
+  logd("Returned mouse mask: %i\n", return_mask);
   // get mouse updates faster at the expense of not registering "clicks"
   mouseinterval(0);
 #ifdef ENABLE_MOUSE_MOVEMENT
@@ -487,6 +487,9 @@ void setup_colors() {
 /* Update canvas with character at cursor current position.
  *
  * Changes the canvas and updates the ncurses `canvas_win` with the change.
+ *
+ * This will assert the cursor is within canvas bounds in DEBUG mode ONLY, so
+ * bounds checking should be done before calling this.
  */
 void front_setcharcursor(char ch) {
   canvas_scharyx(view->canvas, cursor->y + view->y, cursor->x + view->x, ch);

src/view.c

@@ -68,3 +68,11 @@ void view_pan_ch(int arrow, View *view) {
 void view_free(View *view) {
   free(view);
 }
+
+/* Check if a coordinate is inside of a view.
+ */
+bool view_isin(View *view, int y, int x) {
+  return ((x < view_max_x) && (x >= 0) &&  // horizontal
+          (y < view_max_y) && (y >= 0)     // vertical
+  );
+}

src/view.h

@@ -24,4 +24,5 @@ void view_move_right(View *view);
 
 void view_pan_ch(int ch, View *view);
 
+bool view_isin(View *view, int y, int x);
 #endif