Tell V8 about the extra memory being held by FileReader objects.

third_party/WebKit/Source/core/fileapi/FileReaderLoader.cpp

 /*
  * Copyright (C) 2010 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 32 matching lines @@
 #include "platform/loader/fetch/ResourceError.h"
 #include "platform/loader/fetch/ResourceRequest.h"
 #include "platform/loader/fetch/ResourceResponse.h"
 #include "platform/wtf/PassRefPtr.h"
 #include "platform/wtf/PtrUtil.h"
 #include "platform/wtf/RefPtr.h"
 #include "platform/wtf/Vector.h"
 #include "platform/wtf/text/Base64.h"
 #include "platform/wtf/text/StringBuilder.h"
 #include "public/platform/WebURLRequest.h"
+#include "v8/include/v8.h"
 
 namespace blink {
 
 FileReaderLoader::FileReaderLoader(ReadType read_type,
                                    FileReaderLoaderClient* client)
     : read_type_(read_type),
       client_(client),
       is_raw_data_converted_(false),
       string_result_(""),
       finished_loading_(false),
       bytes_loaded_(0),
       total_bytes_(-1),
       has_range_(false),
       range_start_(0),
       range_end_(0),
       error_code_(FileError::kOK) {}
 
 FileReaderLoader::~FileReaderLoader() {
   Cleanup();
+  UnreportMemoryUsageToV8();
   if (!url_for_reading_.IsEmpty()) {
     BlobRegistry::RevokePublicBlobURL(url_for_reading_);
   }
 }
 
 void FileReaderLoader::Start(ExecutionContext* execution_context,
                              PassRefPtr<BlobDataHandle> blob_data) {
   DCHECK(execution_context);
   // The blob is read by routing through the request handling layer given a
   // temporary public url.
@@ skipping 54 matching lines @@
     loader_->Cancel();
     loader_ = nullptr;
   }
 
   // If we get any error, we do not need to keep a buffer around.
   if (error_code_) {
     raw_data_.reset();
     string_result_ = "";
     is_raw_data_converted_ = true;
     decoder_.reset();
+    array_buffer_result_ = nullptr;
+    UnreportMemoryUsageToV8();
   }
 }
 
+void FileReaderLoader::ReportAdditionalMemoryUsageToV8(int64_t usage) {
+  if (!usage)
+    return;
+  memory_usage_reported_to_v8_ += usage;

[dmurph, 2017/04/28 02:33:48]

do a bounds check so it doesn't go negative (dcheck maybe)

[michaeln, 2017/04/28 23:08:50]

Done.

+  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(usage);
+}
+
+void FileReaderLoader::UnreportMemoryUsageToV8() {
+  if (!memory_usage_reported_to_v8_)
+    return;
+  v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(
+      -memory_usage_reported_to_v8_);
+  memory_usage_reported_to_v8_ = 0;
+}
+
 void FileReaderLoader::DidReceiveResponse(
     unsigned long,
     const ResourceResponse& response,
     std::unique_ptr<WebDataConsumerHandle> handle) {
   DCHECK(!handle);
   if (response.HttpStatusCode() != 200) {
     Failed(HttpStatusCodeToErrorCode(response.HttpStatusCode()));
     return;
   }
 
@@ skipping 64 matching lines @@
 
   unsigned bytes_appended = raw_data_->Append(data, data_length);
   if (!bytes_appended) {
     raw_data_.reset();
     bytes_loaded_ = 0;
     Failed(FileError::kNotReadableErr);
     return;
   }
   bytes_loaded_ += bytes_appended;
   is_raw_data_converted_ = false;
+  ReportAdditionalMemoryUsageToV8(bytes_appended);
 
   if (client_)
     client_->DidReceiveData();
 }
 
 void FileReaderLoader::DidFinishLoading(unsigned long, double) {
   if (read_type_ != kReadByClient && raw_data_) {
     raw_data_->ShrinkToFit();
     is_raw_data_converted_ = false;
   }
@@ skipping 35 matching lines @@
       return FileError::kSecurityErr;
     case 404:
       return FileError::kNotFoundErr;
     default:
       return FileError::kNotReadableErr;
   }
 }
 
 DOMArrayBuffer* FileReaderLoader::ArrayBufferResult() {
   DCHECK_EQ(read_type_, kReadAsArrayBuffer);
+  if (array_buffer_result_)
+    return array_buffer_result_;
 
   // If the loading is not started or an error occurs, return an empty result.
   if (!raw_data_ || error_code_)
     return nullptr;
 
-  if (array_buffer_result_)
-    return array_buffer_result_;
-
   DOMArrayBuffer* result = DOMArrayBuffer::Create(raw_data_->ToArrayBuffer());
   if (finished_loading_) {
     array_buffer_result_ = result;
+    ReportAdditionalMemoryUsageToV8(-1 * raw_data_->ByteLength());

[dmurph, 2017/04/28 02:33:48]

change to AdjustReportedV8MemoryUsage?

[michaeln, 2017/04/28 23:08:50]

Done.

+    raw_data_.reset();
   }
   return result;
 }
 
 String FileReaderLoader::StringResult() {
   DCHECK_NE(read_type_, kReadAsArrayBuffer);
   DCHECK_NE(read_type_, kReadByClient);
 
-  // If the loading is not started or an error occurs, return an empty result.
-  if (!raw_data_ || error_code_)
-    return string_result_;
-
-  // If already converted from the raw data, return the result now.
-  if (is_raw_data_converted_)
+  if (!raw_data_ || error_code_ || is_raw_data_converted_)
     return string_result_;
 
   switch (read_type_) {
     case kReadAsArrayBuffer:
       // No conversion is needed.
-      break;
+      return string_result_;
     case kReadAsBinaryString:
-      string_result_ = raw_data_->ToString();
-      is_raw_data_converted_ = true;
+      SetStringResult(raw_data_->ToString());
       break;
     case kReadAsText:
-      ConvertToText();
+      SetStringResult(ConvertToText());

[dmurph, 2017/04/28 02:33:48]

Do you need a std::move here?

[michaeln, 2017/04/28 23:08:50]

I don't think that would do anything, SetStringResult takes a const ref as
input.

       break;
     case kReadAsDataURL:
       // Partial data is not supported when reading as data URL.
       if (finished_loading_)
-        ConvertToDataURL();
+        SetStringResult(ConvertToDataURL());
       break;
     default:
       NOTREACHED();
   }
 
+  if (finished_loading_) {
+    DCHECK(is_raw_data_converted_);
+    ReportAdditionalMemoryUsageToV8(-1 * raw_data_->ByteLength());
+    raw_data_.reset();
+  }
   return string_result_;
 }
 
-void FileReaderLoader::ConvertToText() {
+void FileReaderLoader::SetStringResult(const String& result) {
+  ReportAdditionalMemoryUsageToV8(-1 * string_result_.CharactersSizeInBytes());
   is_raw_data_converted_ = true;
+  string_result_ = result;
+  ReportAdditionalMemoryUsageToV8(string_result_.CharactersSizeInBytes());
+}
 
-  if (!bytes_loaded_) {
-    string_result_ = "";
-    return;
-  }
+String FileReaderLoader::ConvertToText() {
+  if (!bytes_loaded_)
+    return "";
 
   // Decode the data.
   // The File API spec says that we should use the supplied encoding if it is
   // valid. However, we choose to ignore this requirement in order to be
   // consistent with how WebKit decodes the web content: always has the BOM
   // override the provided encoding.
   // FIXME: consider supporting incremental decoding to improve the perf.
   StringBuilder builder;
   if (!decoder_)
     decoder_ = TextResourceDecoder::Create(
         "text/plain", encoding_.IsValid() ? encoding_ : UTF8Encoding());
   builder.Append(decoder_->Decode(static_cast<const char*>(raw_data_->Data()),
                                   raw_data_->ByteLength()));
 
   if (finished_loading_)
     builder.Append(decoder_->Flush());
 
-  string_result_ = builder.ToString();
+  return builder.ToString();
 }
 
-void FileReaderLoader::ConvertToDataURL() {
-  is_raw_data_converted_ = true;
-
+String FileReaderLoader::ConvertToDataURL() {
   StringBuilder builder;
   builder.Append("data:");
 
-  if (!bytes_loaded_) {
-    string_result_ = builder.ToString();
-    return;
-  }
+  if (!bytes_loaded_)
+    return builder.ToString();
 
   builder.Append(data_type_);
   builder.Append(";base64,");
 
   Vector<char> out;
   Base64Encode(static_cast<const char*>(raw_data_->Data()),
                raw_data_->ByteLength(), out);
   out.push_back('\0');
   builder.Append(out.data());
 
-  string_result_ = builder.ToString();
+  return builder.ToString();
 }
 
 void FileReaderLoader::SetEncoding(const String& encoding) {
   if (!encoding.IsEmpty())
     encoding_ = WTF::TextEncoding(encoding);
 }
 
 }  // namespace blink