From 16ecb96922e2f1389cd634a2b908df0a72f8ac1f Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 24 Feb 2023 19:53:47 -0700
Subject: [PATCH] [wasm-api] Return success from buffer_contents_realloc

---
 src/hb-wasm-api-buffer.hh  | 38 ++++++++++++++++++++++++++------------
 src/hb-wasm-api-list.hh    |  2 +-
 src/hb-wasm-api.h          |  6 +++---
 src/wasm-graphite/shape.cc |  3 ++-
 4 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/src/hb-wasm-api-buffer.hh b/src/hb-wasm-api-buffer.hh
index a89fc3968..78d44b572 100644
--- a/src/hb-wasm-api-buffer.hh
+++ b/src/hb-wasm-api-buffer.hh
@@ -35,35 +35,49 @@ namespace wasm {
 static_assert (sizeof (glyph_info_t) == sizeof (hb_glyph_info_t), "");
 static_assert (sizeof (glyph_position_t) == sizeof (hb_glyph_position_t), "");
 
-HB_WASM_API (void, buffer_contents_realloc) (HB_WASM_EXEC_ENV
-					     ptr_d(buffer_contents_t, contents),
-					     uint32_t size)
+HB_WASM_API (bool_t, buffer_contents_realloc) (HB_WASM_EXEC_ENV
+					       ptr_d(buffer_contents_t, contents),
+					       uint32_t size)
 {
   HB_PTR_PARAM (buffer_contents_t, contents);
   if (unlikely (!contents))
-    return;
+    return false;
 
   if (size <= contents->length)
-    return;
+    return true;
 
   unsigned bytes;
   if (hb_unsigned_mul_overflows (size, sizeof (glyph_info_t), &bytes))
-    return;
+    return false;
 
   // TODO bounds check?
   uint32_t infoptr = contents->info;
   uint32_t posptr = contents->pos;
+
   const char *info = (const char *) addr_app_to_native (infoptr);
   const char *pos = (const char *) addr_app_to_native (posptr);
 
-  contents->info = wasm_runtime_module_dup_data (module_inst, info, bytes);
-  contents->pos = wasm_runtime_module_dup_data (module_inst, pos, bytes);
+  uint32_t new_info = wasm_runtime_module_dup_data (module_inst, info, bytes);
+  uint32_t new_pos = wasm_runtime_module_dup_data (module_inst, pos, bytes);
 
-  module_free (infoptr);
-  module_free (posptr);
+  if (likely (new_info))
+  {
+    contents->info = new_info;
+    module_free (infoptr);
+  }
+  if (likely (new_pos))
+  {
+    contents->pos = new_pos;
+    module_free (posptr);
+  }
 
-  // TODO Check success
-  contents->length = size;
+  if (likely (new_info && new_pos))
+  {
+    contents->length = size;
+    return true;
+  }
+
+  return false;
 }
 
 HB_WASM_API (void, buffer_contents_free) (HB_WASM_EXEC_ENV
diff --git a/src/hb-wasm-api-list.hh b/src/hb-wasm-api-list.hh
index 8d05f2914..14ba384fa 100644
--- a/src/hb-wasm-api-list.hh
+++ b/src/hb-wasm-api-list.hh
@@ -58,7 +58,7 @@ static NativeSymbol _hb_wasm_native_symbols[] =
 
   /* buffer */
   NATIVE_SYMBOL ("(i)",		buffer_contents_free),
-  NATIVE_SYMBOL ("(ii)",	buffer_contents_realloc),
+  NATIVE_SYMBOL ("(ii)i",	buffer_contents_realloc),
   NATIVE_SYMBOL ("(ii)",	buffer_copy_contents),
   NATIVE_SYMBOL ("(ii)i",	buffer_set_contents),
   NATIVE_SYMBOL ("(i)i",	buffer_get_direction),
diff --git a/src/hb-wasm-api.h b/src/hb-wasm-api.h
index 515883566..ea3aa6190 100644
--- a/src/hb-wasm-api.h
+++ b/src/hb-wasm-api.h
@@ -140,9 +140,9 @@ typedef struct
   ptr_t(glyph_position_t) pos;
 } buffer_contents_t;
 
-HB_WASM_API (void, buffer_contents_realloc) (HB_WASM_EXEC_ENV
-					     ptr_d(buffer_contents_t, contents),
-					     uint32_t size);
+HB_WASM_API (bool_t, buffer_contents_realloc) (HB_WASM_EXEC_ENV
+					       ptr_d(buffer_contents_t, contents),
+					       uint32_t size);
 
 HB_WASM_API (void, buffer_contents_free) (HB_WASM_EXEC_ENV
 					  ptr_d(buffer_contents_t, contents));
diff --git a/src/wasm-graphite/shape.cc b/src/wasm-graphite/shape.cc
index 24b1b5fe1..80ef1c500 100644
--- a/src/wasm-graphite/shape.cc
+++ b/src/wasm-graphite/shape.cc
@@ -113,7 +113,8 @@ shape (void *shape_plan,
   };
 
   length = glyph_count;
-  buffer_contents_realloc (&contents, length);
+  if (!buffer_contents_realloc (&contents, length))
+    return false;
   cluster_t *clusters = (cluster_t *) malloc (length * sizeof (cluster_t));
   uint32_t *gids = (uint32_t *) malloc (length * sizeof (uint32_t));
   if (!clusters || !gids)