Fix the support for 0x0 sized terminals (adb shell)

libr/cons/canvas.c

@@ -12,7 +12,7 @@ R_API void r_cons_canvas_free (RConsCanvas *c) {
 
 R_API void r_cons_canvas_clear (RConsCanvas *c) {
 	int y;
-	if (c->b) {
+	if (c && c->b) {
 		memset (c->b, '\n', c->blen);
 		c->b[c->blen] = 0;
 		for (y = 0; y<c->h; y++)
@@ -43,6 +43,7 @@ R_API RConsCanvas* r_cons_canvas_new (int w, int h) {
 
 R_API int r_cons_canvas_gotoxy(RConsCanvas *c, int x, int y) {
 	int ret = R_TRUE;
+	if (!c) return 0;
 	x += c->sx;
 	y += c->sy;
 	if (x >= c->w) {
@@ -85,7 +86,10 @@ static char *getrow (char *p, char **n) {
 
 static char *prefixline(RConsCanvas *c, int *left) {
 	int x;
-	char *p = c->b + (c->y * c->w);
+	char *p;
+	if (!c)
+		return NULL;
+	p = c->b + (c->y * c->w);
 	for (x = 0; x<c->x; x++) {
 		if (p[x] == '\n')
 			p[x] = ' ';
@@ -128,10 +132,11 @@ R_API void r_cons_canvas_write(RConsCanvas *c, const char *_s) {
 
 R_API char *r_cons_canvas_to_string(RConsCanvas *c) {
 	int x, y, olen = 0;
-	char *o = malloc (c->w*(c->h+1));
+	char *o, *b;
-	char *b = c->b;
+	if (!c) return NULL;
-	if (!o)
+	b = c->b;
-		return NULL;
+	o = malloc (c->w*(c->h+1));
+	if (!o) return NULL;
 	for (y = 0; y<c->h; y++) {
 		for (x = 0; x<c->w; x++) {
 			int p = x + (y*c->w);
@@ -156,7 +161,7 @@ R_API void r_cons_canvas_print(RConsCanvas *c) {
 R_API int r_cons_canvas_resize(RConsCanvas *c, int w, int h) {
 	int blen = (w+1)*h;
 	char *b = NULL;
-	if (w < 0) return R_FALSE;
+	if (!c || w < 0) return R_FALSE;
 	b = realloc (c->b, blen+1);
 	if (!b) return R_FALSE;
 	c->blen = blen;

libr/cons/cons.c

@@ -579,6 +579,7 @@ R_API int r_cons_get_cursor(int *rows) {
 	return col;
 }
 
+// XXX: if this function returns <0 in rows or cols expect MAYHEM
 R_API int r_cons_get_size(int *rows) {
 #if EMSCRIPTEN
 	I.columns = 80;
@@ -614,12 +615,25 @@ R_API int r_cons_get_size(int *rows) {
 		I.rows = 23;
 	}
 #endif
-	if (rows)
+#if SIMULATE_ADB_SHELL
-		*rows = I.rows;
+	I.rows = 0;
+	I.columns = 0;
+#endif
+#if SIMULATE_MAYHEM
+	// expect tons of crashes
+	I.rows = -1;
+	I.columns = -1;
+#endif
+	if (I.rows<0)
+		I.rows = 0;
+	if (I.columns<0)
+		I.columns = 0;
 	if (I.force_columns) I.columns = I.force_columns;
 	if (I.force_rows) I.rows = I.force_rows;
 	if (I.fix_columns) I.columns += I.fix_columns;
 	if (I.fix_rows) I.rows += I.fix_rows;
+	if (rows)
+		*rows = I.rows;
 	I.rows = R_MAX (0, I.rows);
 	return R_MAX (0, I.columns);
 }

libr/core/graph.c

@@ -46,6 +46,8 @@ static Edge edges[] = {
 static void Node_print(RConsCanvas *can, Node *n, int cur) {
 	char title[128];
 
+	if (!can)
+		return;
 	n->w = r_str_bounds (n->text, &n->h);
 	n->w += 4;
 	n->h += 3;
@@ -81,11 +83,11 @@ static void Node_print(RConsCanvas *can, Node *n, int cur) {
 static void Edge_print(RConsCanvas *can, Node *a, Node *b, int nth) {
 	int x, y, x2, y2;
 	int xinc = 3+(nth*3);
-	x = a->x+xinc;
+	x = a->x + xinc;
-	y = a->y+a->h;
+	y = a->y + a->h;
-	x2 = b->x+xinc;
+	x2 = b->x + xinc;
 	y2 = b->y;
-	L (x,y,x2,y2);
+	L (x, y, x2, y2);
 }
 
 static int Edge_node(Edge *edges, int cur, int nth) {
@@ -322,6 +324,9 @@ static void r_core_graph_refresh (RCore *core) {
 	char title[128];
 	int i, h, w = r_cons_get_size (&h);
 	r_cons_clear00 ();
+	if (!can) {
+		return;
+	}
 	r_cons_canvas_resize (can, w, h);
 	r_cons_canvas_clear (can);
 
@@ -362,6 +367,10 @@ R_API int r_core_visual_graph(RCore *core, RAnalFunction *_fcn) {
 	}
 	w = r_cons_get_size (&h);
 	can = r_cons_canvas_new (w-1, h-1);
+	if (!can) {
+		eprintf ("Cannot create RCons.canvas context\n");
+		return R_FALSE;
+	}
 
 	n_nodes = bbNodes (core, fcn, &nodes);
 	if (!nodes) {

libr/core/visual.c

@@ -1393,6 +1393,11 @@ R_API int r_core_visual(RCore *core, const char *input) {
 	ut64 scrseek;
 	int wheel, flags, ch;
 
+	if (r_cons_get_size(&ch)<1 || ch<1) {
+		eprintf ("Cannot create Visual context. Use scr.fix_{columns|rows}\n");
+		return 0;
+	}
+
 	obs = core->blocksize;
 	//r_cons_set_cup (R_TRUE);
 
@@ -1408,7 +1413,7 @@ R_API int r_core_visual(RCore *core, const char *input) {
 	teefile = r_cons_singleton ()->teefile;
 	r_cons_singleton ()->teefile = "";
 
-	core->print->flags |=  R_PRINT_FLAGS_ADDRMOD;
+	core->print->flags |= R_PRINT_FLAGS_ADDRMOD;
 	do {
 		wheel = r_config_get_i (core->config, "scr.wheel");
 		r_cons_show_cursor (R_FALSE);