From cef1cd19ff31c3bcb1f4b52b53aed1315f8a0264 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Sat, 3 Oct 2020 09:45:28 -0400
Subject: gsk: Avoid long lines in serialized nodes

When encoding big blobs of data in base64, insert newlines.
Base64 allows it, CSS allows it, so not need to make GtkTextView
struggle with multi-megabyte lines.

Update nodeparser tests to reflect this change.
---
 gsk/gskrendernodeparser.c | 71 ++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 61 insertions(+), 10 deletions(-)

(limited to 'gsk')

diff --git a/gsk/gskrendernodeparser.c b/gsk/gskrendernodeparser.c
index c07b749bf6..320f74a13c 100644
--- a/gsk/gskrendernodeparser.c
+++ b/gsk/gskrendernodeparser.c
@@ -2202,10 +2202,57 @@ cairo_destroy_array (gpointer array)
   g_byte_array_free (array, TRUE);
 }
 
+static void
+append_escaping_newlines (GString    *str,
+                          const char *string)
+{
+  gsize len;
+
+  do {
+    len = strcspn (string, "\n");
+    g_string_append_len (str, string, len);
+    string += len;
+    g_string_append (str, "\\\n");
+    string++;
+  } while (*string);
+}
+
+/* like g_base64 encode, but breaks lines
+ * in CSS-compatible way
+ */
+static char *
+base64_encode_with_linebreaks (const guchar *data,
+                               gsize         len)
+{
+  gsize max;
+  char *out;
+  int state = 0, outlen;
+  int save = 0;
+
+  g_return_val_if_fail (data != NULL || len == 0, NULL);
+
+  /* We can use a smaller limit here, since we know the saved state is 0,
+     +1 is needed for trailing \0, also check for unlikely integer overflow */
+  g_return_val_if_fail (len < ((G_MAXSIZE - 1) / 4 - 1) * 3, NULL);
+
+  max = (len / 3 + 1) * 4 + 1;
+  max += 2 * (max / 76);
+
+  out = g_malloc (max);
+
+  outlen = g_base64_encode_step (data, len, TRUE, out, &state, &save);
+  outlen += g_base64_encode_close (TRUE, out + outlen, &state, &save);
+  out[outlen] = '\0';
+
+  return out;
+}
+
 static void
 render_node_print (Printer       *p,
                    GskRenderNode *node)
 {
+  char *b64;
+
   switch (gsk_render_node_get_node_type (node))
     {
     case GSK_CONTAINER_NODE:
@@ -2518,7 +2565,6 @@ render_node_print (Printer       *p,
         GdkTexture *texture = gsk_texture_node_get_texture (node);
         cairo_surface_t *surface;
         GByteArray *array;
-        char *b64;
 
         start_node (p, "texture");
         append_rect_param (p, "bounds", &node->bounds);
@@ -2526,13 +2572,15 @@ render_node_print (Printer       *p,
         surface = gdk_texture_download_surface (texture);
         array = g_byte_array_new ();
         cairo_surface_write_to_png_stream (surface, cairo_write_array, array);
-        b64 = g_base64_encode (array->data, array->len);
 
         _indent (p);
-        g_string_append_printf (p->str, "texture: url(\"data:image/png;base64,%s\");\n", b64);
+        g_string_append (p->str, "texture: url(\"data:image/png;base64,");
+        b64 = base64_encode_with_linebreaks (array->data, array->len);
+        append_escaping_newlines (p->str, b64);
+        g_free (b64);
+        g_string_append (p->str, "\");\n");
         end_node (p);
 
-        g_free (b64);
         g_byte_array_free (array, TRUE);
         cairo_surface_destroy (surface);
       }
@@ -2828,7 +2876,6 @@ render_node_print (Printer       *p,
       {
         cairo_surface_t *surface = gsk_cairo_node_peek_surface (node);
         GByteArray *array;
-        char *b64;
 
         start_node (p, "cairo");
         append_rect_param (p, "bounds", &node->bounds);
@@ -2837,12 +2884,14 @@ render_node_print (Printer       *p,
           {
             array = g_byte_array_new ();
             cairo_surface_write_to_png_stream (surface, cairo_write_array, array);
-            b64 = g_base64_encode (array->data, array->len);
 
             _indent (p);
-            g_string_append_printf (p->str, "pixels: url(\"data:image/png;base64,%s\");\n", b64);
-
+            g_string_append (p->str, "pixels: url(\"data:image/png;base64,");
+            b64 = base64_encode_with_linebreaks (array->data, array->len);
+            append_escaping_newlines (p->str, b64);
             g_free (b64);
+            g_string_append (p->str, "\");\n");
+
             g_byte_array_free (array, TRUE);
 
 #ifdef CAIRO_HAS_SCRIPT_SURFACE
@@ -2856,10 +2905,12 @@ render_node_print (Printer       *p,
 
                 if (cairo_script_from_recording_surface (script, surface) == CAIRO_STATUS_SUCCESS)
                   {
-                    b64 = g_base64_encode (array->data, array->len);
                     _indent (p);
-                    g_string_append_printf (p->str, "script: url(\"data:;base64,%s\");\n", b64);
+                    g_string_append (p->str, "script: url(\"data:;base64,");
+                    b64 = base64_encode_with_linebreaks (array->data, array->len);
+                    append_escaping_newlines (p->str, b64);
                     g_free (b64);
+                    g_string_append (p->str, "\");\n");
                   }
 
                 /* because Cairo is stupid and writes to the device after we finished it,
-- 
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