[iOS] Re-enable JSON parsing in PromoResourceService

Following the WebResource componentization, the parsing of JSON resource
has to be updated on iOS.
The JSON parsing code was removed:
https://codereview.chromium.org/1291543004/diff/120001/ios/chrome/browser/web_resource/ios_web_resource_service.cc
This CL re-adds the code, adapted to the new architecture.

BUG=526299

Review URL: https://codereview.chromium.org/1310173009

Cr-Commit-Position: refs/heads/master@{#347710}

6 files changed, 229 insertions, 0 deletions

diff --git a/ios/chrome/browser/web_resource/OWNERS b/ios/chrome/browser/web_resource/OWNERS
new file mode 100644
index 0000000..58c6484
--- /dev/null
+++ b/ios/chrome/browser/web_resource/OWNERS
@@ -0,0 +1,3 @@
+achuith@chromium.org
+dbeam@chromium.org
+rsesek@chromium.org
diff --git a/ios/chrome/browser/web_resource/web_resource_util.cc b/ios/chrome/browser/web_resource/web_resource_util.cc
new file mode 100644
index 0000000..e11dedb
--- /dev/null
+++ b/ios/chrome/browser/web_resource/web_resource_util.cc
@@ -0,0 +1,79 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ios/chrome/browser/web_resource/web_resource_util.h"
+
+#include "base/bind.h"
+#include "base/json/json_reader.h"
+#include "base/location.h"
+#include "base/task_runner.h"
+#include "base/task_runner_util.h"
+#include "base/values.h"
+#include "ios/web/public/web_thread.h"
+
+namespace web_resource {
+
+namespace {
+
+const char kInvalidDataTypeError[] =
+    "Data from web resource server is missing or not valid JSON.";
+
+const char kUnexpectedJSONFormatError[] =
+    "Data from web resource server does not have expected format.";
+
+// Runs |error_callback| with |error| on |task_runner|.
+void PostErrorTask(base::TaskRunner* task_runner,
+                   const WebResourceService::ErrorCallback& error_callback,
+                   const char error[]) {
+  task_runner->PostTask(FROM_HERE,
+                        base::Bind(error_callback, std::string(error)));
+}
+
+// Parses |data| as a JSON string and calls back on |task_runner|.
+// Must not be called on the UI thread, for performance reasons.
+void ParseJSONOnBackgroundThread(
+    base::TaskRunner* task_runner,
+    const std::string& data,
+    const WebResourceService::SuccessCallback& success_callback,
+    const WebResourceService::ErrorCallback& error_callback) {
+  if (data.empty()) {
+    PostErrorTask(task_runner, error_callback, kInvalidDataTypeError);
+    return;
+  }
+
+  scoped_ptr<base::Value> value(base::JSONReader::Read(data));
+  if (!value.get()) {
+    // Page information not properly read, or corrupted.
+    PostErrorTask(task_runner, error_callback, kInvalidDataTypeError);
+    return;
+  }
+
+  if (!value->IsType(base::Value::TYPE_DICTIONARY)) {
+    PostErrorTask(task_runner, error_callback, kUnexpectedJSONFormatError);
+    return;
+  }
+
+  task_runner->PostTask(FROM_HERE,
+                        base::Bind(success_callback, base::Passed(&value)));
+}
+
+// Starts the parsing of |data| as a JSON string asynchronously on a background
+// thread. Can be called from the UI thread.
+void StartParseJSONAsync(
+    const std::string& data,
+    const WebResourceService::SuccessCallback& success_callback,
+    const WebResourceService::ErrorCallback& error_callback) {
+  web::WebThread::PostBlockingPoolTask(
+      FROM_HERE, base::Bind(&ParseJSONOnBackgroundThread,
+                            base::ThreadTaskRunnerHandle::Get(), data,
+                            success_callback, error_callback));
+}
+
+}  // namespace
+
+WebResourceService::ParseJSONCallback GetIOSChromeParseJSONCallback() {
+  return base::Bind(&StartParseJSONAsync);
+}
+
+}  // namespace web_resource
diff --git a/ios/chrome/browser/web_resource/web_resource_util.h b/ios/chrome/browser/web_resource/web_resource_util.h
new file mode 100644
index 0000000..6b14203
--- /dev/null
+++ b/ios/chrome/browser/web_resource/web_resource_util.h
@@ -0,0 +1,18 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_UTIL_H_
+#define IOS_CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_UTIL_H_
+
+#include "components/web_resource/web_resource_service.h"
+
+namespace web_resource {
+
+// Returns a ParseJSONCallback that parses JSON on a background thread.
+// Generates an error if the data is not a dictionary.
+WebResourceService::ParseJSONCallback GetIOSChromeParseJSONCallback();
+
+}  // namespace web_resource
+
+#endif  // IOS_CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_UTIL_H_
diff --git a/ios/chrome/browser/web_resource/web_resource_util_unittest.cc b/ios/chrome/browser/web_resource/web_resource_util_unittest.cc
new file mode 100644
index 0000000..92a1585
--- /dev/null
+++ b/ios/chrome/browser/web_resource/web_resource_util_unittest.cc
@@ -0,0 +1,126 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ios/chrome/browser/web_resource/web_resource_util.h"
+
+#include <string>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/stringprintf.h"
+#include "base/values.h"
+#include "ios/web/public/web_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace web_resource {
+
+class WebResourceUtilTest : public testing::Test {
+ protected:
+  WebResourceUtilTest() : error_called_(false), success_called_(false) {}
+  ~WebResourceUtilTest() override {}
+
+  WebResourceService::SuccessCallback GetSuccessCallback() {
+    return base::Bind(&WebResourceUtilTest::OnParseSuccess,
+                      base::Unretained(this));
+  }
+
+  WebResourceService::ErrorCallback GetErrorCallback() {
+    return base::Bind(&WebResourceUtilTest::OnParseError,
+                      base::Unretained(this));
+  }
+
+  // Called on success.
+  void OnParseSuccess(scoped_ptr<base::Value> value) {
+    success_called_ = true;
+    value_ = value.Pass();
+  }
+
+  // Called on error.
+  void OnParseError(const std::string& error) {
+    error_called_ = true;
+    error_ = error;
+  }
+
+  void FlushBackgroundTasks() {
+    // The function is not synchronous, callbacks are not called before flushing
+    // the tasks.
+    EXPECT_FALSE(success_called_);
+    EXPECT_FALSE(error_called_);
+
+    web::WebThread::GetBlockingPool()->FlushForTesting();
+    loop_.RunUntilIdle();
+  }
+
+  base::MessageLoop loop_;
+  std::string error_;
+  scoped_ptr<base::Value> value_;
+  bool error_called_;
+  bool success_called_;
+};
+
+TEST_F(WebResourceUtilTest, Success) {
+  const std::string kExpectedKey("foo");
+  const std::string kExpectedValue("bar");
+  std::string json = base::StringPrintf("{\"%s\":\"%s\"}", kExpectedKey.c_str(),
+                                        kExpectedValue.c_str());
+  GetIOSChromeParseJSONCallback().Run(json, GetSuccessCallback(),
+                                      GetErrorCallback());
+
+  FlushBackgroundTasks();
+
+  // The success callback is called with the reference value.
+  EXPECT_FALSE(error_called_);
+  EXPECT_TRUE(success_called_);
+
+  base::DictionaryValue* dictionary = nullptr;
+  ASSERT_TRUE(value_->GetAsDictionary(&dictionary));
+  EXPECT_EQ(1u, dictionary->size());
+  base::Value* actual_value = nullptr;
+  ASSERT_TRUE(dictionary->Get(kExpectedKey, &actual_value));
+  std::string actual_value_as_string;
+  EXPECT_TRUE(actual_value->GetAsString(&actual_value_as_string));
+  EXPECT_EQ(kExpectedValue, actual_value_as_string);
+}
+
+// Only DictionartValues are expected.
+TEST_F(WebResourceUtilTest, UnexpectedValue) {
+  GetIOSChromeParseJSONCallback().Run("foo", GetSuccessCallback(),
+                                      GetErrorCallback());
+
+  FlushBackgroundTasks();
+
+  // The error callback is called.
+  EXPECT_TRUE(error_called_);
+  EXPECT_FALSE(success_called_);
+  EXPECT_FALSE(error_.empty());
+}
+
+// Empty data is not expected.
+TEST_F(WebResourceUtilTest, EmptyValue) {
+  GetIOSChromeParseJSONCallback().Run(std::string(), GetSuccessCallback(),
+                                      GetErrorCallback());
+
+  FlushBackgroundTasks();
+
+  // The error callback is called.
+  EXPECT_TRUE(error_called_);
+  EXPECT_FALSE(success_called_);
+  EXPECT_FALSE(error_.empty());
+}
+
+// Wrong syntax.
+TEST_F(WebResourceUtilTest, SyntaxError) {
+  GetIOSChromeParseJSONCallback().Run("%$[", GetSuccessCallback(),
+                                      GetErrorCallback());
+
+  FlushBackgroundTasks();
+
+  // The error callback is called.
+  EXPECT_TRUE(error_called_);
+  EXPECT_FALSE(success_called_);
+  EXPECT_FALSE(error_.empty());
+}
+
+}  // namespace web_resource
diff --git a/ios/chrome/ios_chrome.gyp b/ios/chrome/ios_chrome.gyp
index d20c369..8ce37d2 100644
--- a/ios/chrome/ios_chrome.gyp
+++ b/ios/chrome/ios_chrome.gyp
@@ -453,6 +453,8 @@
         'browser/web/web_view_type_util.mm',
         'browser/web_data_service_factory.cc',
         'browser/web_data_service_factory.h',
+        'browser/web_resource/web_resource_util.cc',
+        'browser/web_resource/web_resource_util.h',
         'browser/xcallback_parameters.h',
         'browser/xcallback_parameters.mm',
       ],
diff --git a/ios/chrome/ios_chrome_tests.gyp b/ios/chrome/ios_chrome_tests.gyp
index 2a148eb..2847f31 100644
--- a/ios/chrome/ios_chrome_tests.gyp
+++ b/ios/chrome/ios_chrome_tests.gyp
@@ -57,6 +57,7 @@
         'browser/ui/native_content_controller_unittest.mm',
         'browser/ui/ui_util_unittest.mm',
         'browser/ui/uikit_ui_util_unittest.mm',
+        'browser/web_resource/web_resource_util_unittest.cc',
         'common/string_util_unittest.mm',
       ],
       'actions': [