Expose v8::TypedArray::kMaxLength.

jeremyroman · Commit Bot · commit 19fee8b24b2f · 2017-08-02T22:15:57.000Z
There is an API check failure if values larger than i::Smi::kMaxValue are provided, but it is inconvenient for API users to know what this value is (and SIZE_MAX and INT_MAX are both incorrect). This is analogous to v8::String::kMaxLength. Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng Bug: chromium:750788 Change-Id: Ic3e0da62aeacfeb996122595232aa0ea8744517e Reviewed-on: https://chromium-review.googlesource.com/594677 Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Commit-Queue: Jeremy Roman <jbroman@chromium.org> Cr-Commit-Position: refs/heads/master@{#47099}
diff --git a/include/v8.h b/include/v8.h
@@ -4492,6 +4492,12 @@ class V8_EXPORT ArrayBufferView : public Object {
  */
 class V8_EXPORT TypedArray : public ArrayBufferView {
  public:
+  /*
+   * The largest typed array size that can be constructed using New.
+   */
+  static constexpr size_t kMaxLength =
+      sizeof(void*) == 4 ? (1u << 30) - 1 : (1u << 31) - 1;
+
   /**
    * Number of elements in this typed array
    * (e.g. for Int16Array, |ByteLength|/2).
diff --git a/src/api.cc b/src/api.cc
@@ -8041,13 +8041,16 @@ size_t v8::TypedArray::Length() {
   return static_cast<size_t>(obj->length_value());
 }
 
+static_assert(v8::TypedArray::kMaxLength == i::Smi::kMaxValue,
+              "v8::TypedArray::kMaxLength must match i::Smi::kMaxValue");
+
 #define TYPED_ARRAY_NEW(Type, type, TYPE, ctype, size)                     \
   Local<Type##Array> Type##Array::New(Local<ArrayBuffer> array_buffer,     \
                                       size_t byte_offset, size_t length) { \
     i::Isolate* isolate = Utils::OpenHandle(*array_buffer)->GetIsolate();  \
     LOG_API(isolate, Type##Array, New);                                    \
     ENTER_V8_NO_SCRIPT_NO_EXCEPTION(isolate);                              \
-    if (!Utils::ApiCheck(length <= static_cast<size_t>(i::Smi::kMaxValue), \
+    if (!Utils::ApiCheck(length <= kMaxLength,                             \
                          "v8::" #Type                                      \
                          "Array::New(Local<ArrayBuffer>, size_t, size_t)", \
                          "length exceeds max allowed value")) {            \
@@ -8067,7 +8070,7 @@ size_t v8::TypedArray::Length() {
     LOG_API(isolate, Type##Array, New);                                    \
     ENTER_V8_NO_SCRIPT_NO_EXCEPTION(isolate);                              \
     if (!Utils::ApiCheck(                                                  \
-            length <= static_cast<size_t>(i::Smi::kMaxValue),              \
+            length <= kMaxLength,                                          \
             "v8::" #Type                                                   \
             "Array::New(Local<SharedArrayBuffer>, size_t, size_t)",        \
             "length exceeds max allowed value")) {                         \
