src: extract AllocatedBuffer from env.h

node.gyp

@@ -643,6 +643,8 @@
         'src/aliased_buffer.h',
         'src/aliased_struct.h',
         'src/aliased_struct-inl.h',
+        'src/allocated_buffer.h',
+        'src/allocated_buffer-inl.h'
         'src/async_wrap.h',
         'src/async_wrap-inl.h',
         'src/base_object.h',

src/allocated_buffer-inl.h

@@ -0,0 +1,110 @@
+#ifndef SRC_ALLOCATED_BUFFER_INL_H_
+#define SRC_ALLOCATED_BUFFER_INL_H_
+
+#include "allocated_buffer.h"
+#include "base_object-inl.h"
+#include "node_buffer.h"
+#include "env-inl.h"
+#include "uv.h"
+#include "v8.h"
+#include "util-inl.h"
+#include "node_internals.h"
+
+namespace node {
+
+// It's a bit awkward to define this Buffer::New() overload here, but it
+// avoids a circular dependency with node_internals.h.
+namespace Buffer {
+v8::MaybeLocal<v8::Uint8Array> New(Environment* env,
+                                   v8::Local<v8::ArrayBuffer> ab,
+                                   size_t byte_offset,
+                                   size_t length);
+}
+
+NoArrayBufferZeroFillScope::NoArrayBufferZeroFillScope(
+    IsolateData* isolate_data)
+  : node_allocator_(isolate_data->node_allocator()) {
+  if (node_allocator_ != nullptr) node_allocator_->zero_fill_field()[0] = 0;
+}
+
+NoArrayBufferZeroFillScope::~NoArrayBufferZeroFillScope() {
+  if (node_allocator_ != nullptr) node_allocator_->zero_fill_field()[0] = 1;
+}
+
+AllocatedBuffer AllocatedBuffer::AllocateManaged(
+    Environment* env,
+    size_t size) {
+  NoArrayBufferZeroFillScope no_zero_fill_scope(env->isolate_data());
+  std::unique_ptr<v8::BackingStore> bs =
+      v8::ArrayBuffer::NewBackingStore(env->isolate(), size);
+  return AllocatedBuffer(env, std::move(bs));
+}
+
+AllocatedBuffer::AllocatedBuffer(
+    Environment* env, std::unique_ptr<v8::BackingStore> bs)
+    : env_(env), backing_store_(std::move(bs)) {}
+
+AllocatedBuffer::AllocatedBuffer(
+    Environment* env, uv_buf_t buffer)
+    : env_(env) {
+  if (buffer.base == nullptr) return;
+  auto map = env->released_allocated_buffers();
+  auto it = map->find(buffer.base);
+  CHECK_NE(it, map->end());
+  backing_store_ = std::move(it->second);
+  map->erase(it);
+}
+
+void AllocatedBuffer::Resize(size_t len) {
+  if (len == 0) {
+    backing_store_ = v8::ArrayBuffer::NewBackingStore(env_->isolate(), 0);
+    return;
+  }
+  NoArrayBufferZeroFillScope no_zero_fill_scope(env_->isolate_data());
+  backing_store_ = v8::BackingStore::Reallocate(
+      env_->isolate(), std::move(backing_store_), len);
+}
+
+uv_buf_t AllocatedBuffer::release() {
+  if (data() == nullptr) return uv_buf_init(nullptr, 0);
+
+  CHECK_NOT_NULL(env_);
+  uv_buf_t ret = uv_buf_init(data(), size());
+  env_->released_allocated_buffers()->emplace(
+      ret.base, std::move(backing_store_));
+  return ret;
+}
+
+char* AllocatedBuffer::data() {
+  if (!backing_store_) return nullptr;
+  return static_cast<char*>(backing_store_->Data());
+}
+
+const char* AllocatedBuffer::data() const {
+  if (!backing_store_) return nullptr;
+  return static_cast<char*>(backing_store_->Data());
+}
+
+
+size_t AllocatedBuffer::size() const {
+  if (!backing_store_) return 0;
+  return backing_store_->ByteLength();
+}
+
+void AllocatedBuffer::clear() {
+  backing_store_.reset();
+}
+
+v8::MaybeLocal<v8::Object> AllocatedBuffer::ToBuffer() {
+  v8::Local<v8::ArrayBuffer> ab = ToArrayBuffer();
+  return Buffer::New(env_, ab, 0, ab->ByteLength())
+      .FromMaybe(v8::Local<v8::Uint8Array>());
+}
+
+v8::Local<v8::ArrayBuffer> AllocatedBuffer::ToArrayBuffer() {
+  return v8::ArrayBuffer::New(env_->isolate(), std::move(backing_store_));
+}
+
+}  // namespace node
+
+#endif  // SRC_ALLOCATED_BUFFER_INL_H_

src/allocated_buffer.h

@@ -0,0 +1,73 @@
+#ifndef SRC_ALLOCATED_BUFFER_H_
+#define SRC_ALLOCATED_BUFFER_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "base_object.h"
+#include "uv.h"
+#include "v8.h"
+#include "env.h"
+
+namespace node {
+
+class Environment;
+
+// Disables zero-filling for ArrayBuffer allocations in this scope. This is
+// similar to how we implement Buffer.allocUnsafe() in JS land.
+class NoArrayBufferZeroFillScope{
+ public:
+  inline explicit NoArrayBufferZeroFillScope(IsolateData* isolate_data);
+  inline ~NoArrayBufferZeroFillScope();
+
+ private:
+  NodeArrayBufferAllocator* node_allocator_;
+
+  friend class Environment;
+};
+
+// A unique-pointer-ish object that is compatible with the JS engine's
+// ArrayBuffer::Allocator.
+// TODO(addaleax): We may want to start phasing this out as it's only a
+// thin wrapper around v8::BackingStore at this point
+struct AllocatedBuffer {
+ public:
+  // Utilities that allocate memory using the Isolate's ArrayBuffer::Allocator.
+  // In particular, using AllocateManaged() will provide a RAII-style object
+  // with easy conversion to `Buffer` and `ArrayBuffer` objects.
+  inline static AllocatedBuffer AllocateManaged(Environment* env, size_t size);
+
+  AllocatedBuffer() = default;
+  inline AllocatedBuffer(
+      Environment* env, std::unique_ptr<v8::BackingStore> bs);
+  // For this constructor variant, `buffer` *must* come from an earlier call
+  // to .release
+  inline AllocatedBuffer(Environment* env, uv_buf_t buffer);
+
+  inline void Resize(size_t len);
+
+  inline uv_buf_t release();
+  inline char* data();
+  inline const char* data() const;
+  inline size_t size() const;
+  inline void clear();
+
+  inline v8::MaybeLocal<v8::Object> ToBuffer();
+  inline v8::Local<v8::ArrayBuffer> ToArrayBuffer();
+
+  AllocatedBuffer(AllocatedBuffer&& other) = default;
+  AllocatedBuffer& operator=(AllocatedBuffer&& other) = default;
+  AllocatedBuffer(const AllocatedBuffer& other) = delete;
+  AllocatedBuffer& operator=(const AllocatedBuffer& other) = delete;
+
+ private:
+  Environment* env_ = nullptr;
+  std::unique_ptr<v8::BackingStore> backing_store_;
+
+  friend class Environment;
+};
+
+}  // namespace node
+
+#endif  // NODE_WANT_INTERNALS
+
+#endif  // SRC_ALLOCATED_BUFFER_H_

src/env-inl.h

@@ -867,117 +867,9 @@ inline IsolateData* Environment::isolate_data() const {
   return isolate_data_;
 }
 
-inline char* Environment::AllocateUnchecked(size_t size) {
-  return static_cast<char*>(
-      isolate_data()->allocator()->AllocateUninitialized(size));
-}
-
-inline char* Environment::Allocate(size_t size) {
-  char* ret = AllocateUnchecked(size);
-  CHECK_NE(ret, nullptr);
-  return ret;
-}
-
-inline void Environment::Free(char* data, size_t size) {
-  if (data != nullptr)
-    isolate_data()->allocator()->Free(data, size);
-}
-
-inline AllocatedBuffer Environment::AllocateManaged(size_t size, bool checked) {
-  char* data = checked ? Allocate(size) : AllocateUnchecked(size);
-  if (data == nullptr) size = 0;
-  return AllocatedBuffer(this, uv_buf_init(data, size));
-}
-
-inline AllocatedBuffer::AllocatedBuffer(Environment* env, uv_buf_t buf)
-    : env_(env), buffer_(buf) {}
-
-inline void AllocatedBuffer::Resize(size_t len) {
-  // The `len` check is to make sure we don't end up with `nullptr` as our base.
-  char* new_data = env_->Reallocate(buffer_.base, buffer_.len,
-                                    len > 0 ? len : 1);
-  CHECK_NOT_NULL(new_data);
-  buffer_ = uv_buf_init(new_data, len);
-}
-
-inline uv_buf_t AllocatedBuffer::release() {
-  uv_buf_t ret = buffer_;
-  buffer_ = uv_buf_init(nullptr, 0);
-  return ret;
-}
-
-inline char* AllocatedBuffer::data() {
-  return buffer_.base;
-}
-
-inline const char* AllocatedBuffer::data() const {
-  return buffer_.base;
-}
-
-inline size_t AllocatedBuffer::size() const {
-  return buffer_.len;
-}
-
-inline AllocatedBuffer::AllocatedBuffer(Environment* env)
-    : env_(env), buffer_(uv_buf_init(nullptr, 0)) {}
-
-inline AllocatedBuffer::AllocatedBuffer(AllocatedBuffer&& other)
-    : AllocatedBuffer() {
-  *this = std::move(other);
-}
-
-inline AllocatedBuffer& AllocatedBuffer::operator=(AllocatedBuffer&& other) {
-  clear();
-  env_ = other.env_;
-  buffer_ = other.release();
-  return *this;
-}
-
-inline AllocatedBuffer::~AllocatedBuffer() {
-  clear();
-}
-
-inline void AllocatedBuffer::clear() {
-  uv_buf_t buf = release();
-  if (buf.base != nullptr) {
-    CHECK_NOT_NULL(env_);
-    env_->Free(buf.base, buf.len);
-  }
-}
-
-// It's a bit awkward to define this Buffer::New() overload here, but it
-// avoids a circular dependency with node_internals.h.
-namespace Buffer {
-v8::MaybeLocal<v8::Object> New(Environment* env,
-                               char* data,
-                               size_t length,
-                               bool uses_malloc);
-}
-
-inline v8::MaybeLocal<v8::Object> AllocatedBuffer::ToBuffer() {
-  CHECK_NOT_NULL(env_);
-  v8::MaybeLocal<v8::Object> obj = Buffer::New(env_, data(), size(), false);
-  if (!obj.IsEmpty()) release();
-  return obj;
-}
-
-inline v8::Local<v8::ArrayBuffer> AllocatedBuffer::ToArrayBuffer() {
-  CHECK_NOT_NULL(env_);
-  uv_buf_t buf = release();
-  auto callback = [](void* data, size_t length, void* deleter_data){
-    CHECK_NOT_NULL(deleter_data);
-
-    static_cast<v8::ArrayBuffer::Allocator*>(deleter_data)
-        ->Free(data, length);
-  };
-  std::unique_ptr<v8::BackingStore> backing =
-      v8::ArrayBuffer::NewBackingStore(buf.base,
-                                       buf.len,
-                                       callback,
-                                       env_->isolate()
-                                          ->GetArrayBufferAllocator());
-  return v8::ArrayBuffer::New(env_->isolate(),
-                              std::move(backing));
+std::unordered_map<char*, std::unique_ptr<v8::BackingStore>>*
+    Environment::released_allocated_buffers() {
+  return &released_allocated_buffers_;
 }
 
 inline void Environment::ThrowError(const char* errmsg) {

src/env.cc

@@ -1,5 +1,5 @@
 #include "env.h"
-
+#include "allocated_buffer-inl.h"
 #include "async_wrap.h"
 #include "base_object-inl.h"
 #include "debug_utils-inl.h"
@@ -1104,25 +1104,6 @@ void Environment::MemoryInfo(MemoryTracker* tracker) const {
   // node, we shift its sizeof() size out of the Environment node.
 }
 
-char* Environment::Reallocate(char* data, size_t old_size, size_t size) {
-  if (old_size == size) return data;
-  // If we know that the allocator is our ArrayBufferAllocator, we can let
-  // if reallocate directly.
-  if (isolate_data()->uses_node_allocator()) {
-    return static_cast<char*>(
-        isolate_data()->node_allocator()->Reallocate(data, old_size, size));
-  }
-  // Generic allocators do not provide a reallocation method; we need to
-  // allocate a new chunk of memory and copy the data over.
-  char* new_data = AllocateUnchecked(size);
-  if (new_data == nullptr) return nullptr;
-  memcpy(new_data, data, std::min(size, old_size));
-  if (size > old_size)
-    memset(new_data + old_size, 0, size - old_size);
-  Free(data, old_size);
-  return new_data;
-}
-
 void Environment::RunWeakRefCleanup() {
   isolate()->ClearKeptObjects();
 }