Rewrite implementation of ClipboardRecentContent in Objective C.

components/open_from_clipboard/clipboard_recent_content_ios.mm

 // 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.
 
 #import "components/open_from_clipboard/clipboard_recent_content_ios.h"
 
 #import <CommonCrypto/CommonDigest.h>
 #include <stddef.h>
 #include <stdint.h>
 #import <UIKit/UIKit.h>
 
 #import "base/ios/ios_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/sys_info.h"
+#import "components/open_from_clipboard/clipboard_recent_content_ios_impl.h"
+#import "net/base/mac/url_conversions.h"
 #include "url/gurl.h"
 #include "url/url_constants.h"
 
-// Bridge that forwards UIApplicationDidBecomeActiveNotification notifications
-// to its delegate.
-@interface ApplicationDidBecomeActiveNotificationListenerBridge : NSObject
+namespace {
+// Schemes accepted by the ClipboardRecentContentIOS.
+const char* kAuthorizedSchemes[] = {
+    url::kHttpScheme, url::kHttpsScheme, url::kDataScheme, url::kAboutScheme,
+};
+}
 
-// Initialize the ApplicationDidBecomeActiveNotificationListenerBridge with
-// |delegate| which must not be null.
-- (instancetype)initWithDelegate:(ClipboardRecentContentIOS*)delegate
-    NS_DESIGNATED_INITIALIZER;
-
-- (instancetype)init NS_UNAVAILABLE;
-
+@interface ClipboardRecentContentMetricsDelegateImpl
+    : NSObject<ClipboardRecentContentMetricsDelegate>
 @end
 
-@implementation ApplicationDidBecomeActiveNotificationListenerBridge {
-  ClipboardRecentContentIOS* _delegate;
-}
+@implementation ClipboardRecentContentMetricsDelegateImpl
 
-- (instancetype)init {
-  NOTREACHED();
-  return nil;
-}
-
-- (instancetype)initWithDelegate:(ClipboardRecentContentIOS*)delegate {
-  DCHECK(delegate);
-  self = [super init];
-  if (self) {
-    _delegate = delegate;
-    [[NSNotificationCenter defaultCenter]
-        addObserver:self
-           selector:@selector(didBecomeActive:)
-               name:UIApplicationDidBecomeActiveNotification
-             object:nil];
-  }
-  return self;
-}
-
-- (void)dealloc {
-  [[NSNotificationCenter defaultCenter] removeObserver:self];
-  [super dealloc];
-}
-
-- (void)didBecomeActive:(NSNotification*)notification {
-  if (_delegate) {
-    _delegate->LoadFromUserDefaults();
-    _delegate->UpdateIfNeeded();
-  }
-}
-
-- (void)disconnect {
-  _delegate = nullptr;
+- (void)onClipboardChanged {
+  base::RecordAction(base::UserMetricsAction("MobileOmniboxClipboardChanged"));

[sdefresne, 2017/04/03 09:27:16]

(outside of the CL) I think action that is recorded is part of the embedder, not
of the component (you just proved it by having another use of the code outside
of the omnibox). So this delegate should be a C++ class passed to the public
ClipboardRecentContent abstract class.

 }
 
 @end
 
-namespace {
-// Key used to store the pasteboard's current change count. If when resuming
-// chrome the pasteboard's change count is different from the stored one, then
-// it means that the pasteboard's content has changed.
-NSString* kPasteboardChangeCountKey = @"PasteboardChangeCount";
-// Key used to store the last date at which it was detected that the pasteboard
-// changed. It is used to evaluate the age of the pasteboard's content.
-NSString* kPasteboardChangeDateKey = @"PasteboardChangeDate";
-// Key used to store the hash of the content of the pasteboard. Whenever the
-// hash changed, the pasteboard content is considered to have changed.
-NSString* kPasteboardEntryMD5Key = @"PasteboardEntryMD5";
-base::TimeDelta kMaximumAgeOfClipboard = base::TimeDelta::FromHours(3);
-// Schemes accepted by the ClipboardRecentContentIOS.
-const char* kAuthorizedSchemes[] = {
-    url::kHttpScheme,
-    url::kHttpsScheme,
-    url::kDataScheme,
-    url::kAboutScheme,
-};
+ClipboardRecentContentIOS::ClipboardRecentContentIOS(
+    const std::string& application_scheme,
+    NSUserDefaults* group_user_defaults) {
+  ClipboardRecentContentMetricsDelegateImpl* metricsDelegate =

[sdefresne, 2017/04/03 09:27:16]

s/metricsDelegate/metrics_delegate/.

[lody, 2017/04/04 13:42:18]

Done.

+      [[ClipboardRecentContentMetricsDelegateImpl alloc] init];
 
-// Compute a hash consisting of the first 4 bytes of the MD5 hash of |string|.
-// This value is used to detect pasteboard content change. Keeping only 4 bytes
-// is a privacy requirement to introduce collision and allow deniability of
-// having copied a given string.
-NSData* WeakMD5FromNSString(NSString* string) {
-  unsigned char hash[CC_MD5_DIGEST_LENGTH];
-  const std::string clipboard = base::SysNSStringToUTF8(string);
-  const char* c_string = clipboard.c_str();
-  CC_MD5(c_string, strlen(c_string), hash);
-  NSData* data = [NSData dataWithBytes:hash length:4];
-  return data;
+  implementation_.reset([[ClipboardRecentContentIOSImpl alloc]
+       initWithDelegate:metricsDelegate
+      authorizedSchemes:GetAuthorizedSchemeList(application_scheme)
+           userDefaults:group_user_defaults]);
 }
 
-}  // namespace
-
 bool ClipboardRecentContentIOS::GetRecentURLFromClipboard(GURL* url) {
   DCHECK(url);
-  UpdateIfNeeded();
-  if (GetClipboardContentAge() > kMaximumAgeOfClipboard) {
-    return false;
-  }
-
-  GURL url_from_pasteboard = URLFromPasteboard();
-  if (url_from_pasteboard.is_valid()) {
-    *url = url_from_pasteboard;
-    return true;
+  NSURL* nsurl = [implementation_ getRecentURLFromClipboard];

[sdefresne, 2017/04/03 09:27:16]

url_from_pasteboard

[lody, 2017/04/04 13:42:18]

Done.

+  if (nsurl != nil) {

[sdefresne, 2017/04/03 09:27:16]

No need to test nsurl for nil, net::GURLWithNSURL() supports nil as part of its
API.

  // Method for creating a valid GURL from a NSURL. This method will return an
  // empty GURL if the |url| is nil.
  NET_EXPORT GURL GURLWithNSURL(NSURL* url);

[lody, 2017/04/04 13:42:18]

Done.

+    GURL tempUrl = net::GURLWithNSURL(nsurl);

[sdefresne, 2017/04/03 09:27:16]

  NSURL* url_from_pasteboard = [implementation_ getRecentURLFromClipboard];
  GURL converted_url = net::GURLWithNSURL(url_from_pasteboard);
  if (!converted_url)
    return false;
  *url = std::move(converted_url);
  return true;

[lody, 2017/04/04 13:42:18]

Done.

+    if (tempUrl.is_valid()) {
+      *url = std::move(tempUrl);
+      return true;
+    }
   }
   return false;
 }
 
+ClipboardRecentContentIOS::~ClipboardRecentContentIOS() {}
+
 base::TimeDelta ClipboardRecentContentIOS::GetClipboardContentAge() const {
-  return base::TimeDelta::FromSeconds(static_cast<int64_t>(
-      -[last_pasteboard_change_date_ timeIntervalSinceNow]));
+  return base::TimeDelta::FromSeconds(
+      static_cast<int64_t>([implementation_ getClipboardContentAge]));
 }
 
 void ClipboardRecentContentIOS::SuppressClipboardContent() {
-  // User cleared the user data. The pasteboard entry must be removed from the
-  // omnibox list. Force entry expiration by setting copy date to 1970.
-  last_pasteboard_change_date_.reset(
-      [[NSDate alloc] initWithTimeIntervalSince1970:0]);
-  SaveToUserDefaults();
-}
-
-void ClipboardRecentContentIOS::UpdateIfNeeded() {
-  if (!HasPasteboardChanged())
-    return;
-
-  base::RecordAction(base::UserMetricsAction("MobileOmniboxClipboardChanged"));
-
-  GURL url_from_pasteboard = URLFromPasteboard();
-  last_pasteboard_change_date_.reset([[NSDate date] retain]);
-  last_pasteboard_change_count_ = [UIPasteboard generalPasteboard].changeCount;
-  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
-  if (!pasteboard_string) {
-    pasteboard_string = @"";
-  }
-  NSData* MD5 = WeakMD5FromNSString(pasteboard_string);
-  last_pasteboard_entry_md5_.reset([MD5 retain]);
-  SaveToUserDefaults();
-}
-
-ClipboardRecentContentIOS::ClipboardRecentContentIOS(
-    const std::string& application_scheme,
-    NSUserDefaults* group_user_defaults)
-    : application_scheme_(application_scheme),
-      shared_user_defaults_([group_user_defaults retain]) {
-  last_pasteboard_change_count_ = NSIntegerMax;
-  LoadFromUserDefaults();
-
-  UpdateIfNeeded();
-
-  // Makes sure |last_pasteboard_change_count_| was properly initialized.
-  DCHECK_NE(last_pasteboard_change_count_, NSIntegerMax);
-  notification_bridge_.reset(
-      [[ApplicationDidBecomeActiveNotificationListenerBridge alloc]
-          initWithDelegate:this]);
-}
-
-bool ClipboardRecentContentIOS::HasPasteboardChanged() const {
-  // If |MD5Changed|, we know for sure there has been at least one pasteboard
-  // copy since last time it was checked.
-  // If the pasteboard content is still the same but the device was not
-  // rebooted, the change count can be checked to see if it changed.
-  // Note: due to a mismatch between the actual behavior and documentation, and
-  // lack of consistency on different reboot scenarios, the change count cannot
-  // be checked after a reboot.
-  // See radar://21833556 for more information.
-  NSInteger change_count = [UIPasteboard generalPasteboard].changeCount;
-  bool change_count_changed = change_count != last_pasteboard_change_count_;
-
-  bool not_rebooted = Uptime() > GetClipboardContentAge();
-  if (not_rebooted)
-    return change_count_changed;
-
-  NSString* pasteboard_string = [[UIPasteboard generalPasteboard] string];
-  if (!pasteboard_string) {
-    pasteboard_string = @"";
-  }
-  NSData* md5 = WeakMD5FromNSString(pasteboard_string);
-  BOOL md5_changed = ![md5 isEqualToData:last_pasteboard_entry_md5_];
-
-  return md5_changed;
-}
-
-ClipboardRecentContentIOS::~ClipboardRecentContentIOS() {
-  [notification_bridge_ disconnect];
-}
-
-GURL ClipboardRecentContentIOS::URLFromPasteboard() {
-  NSString* clipboard_string = [[UIPasteboard generalPasteboard] string];
-  if (!clipboard_string) {
-    return GURL::EmptyGURL();
-  }
-  const std::string clipboard = base::SysNSStringToUTF8(clipboard_string);
-  GURL gurl = GURL(clipboard);
-  if (gurl.is_valid()) {
-    for (size_t i = 0; i < arraysize(kAuthorizedSchemes); ++i) {
-      if (gurl.SchemeIs(kAuthorizedSchemes[i])) {
-        return gurl;
-      }
-    }
-    if (!application_scheme_.empty() &&
-        gurl.SchemeIs(application_scheme_.c_str())) {
-      return gurl;
-    }
-  }
-  return GURL::EmptyGURL();
-}
-
-void ClipboardRecentContentIOS::LoadFromUserDefaults() {
-  last_pasteboard_change_count_ =
-      [shared_user_defaults_ integerForKey:kPasteboardChangeCountKey];
-  last_pasteboard_change_date_.reset(
-      [[shared_user_defaults_ objectForKey:kPasteboardChangeDateKey] retain]);
-  last_pasteboard_entry_md5_.reset(
-      [[shared_user_defaults_ objectForKey:kPasteboardEntryMD5Key] retain]);
-
-  DCHECK(!last_pasteboard_change_date_ ||
-         [last_pasteboard_change_date_ isKindOfClass:[NSDate class]]);
+  [implementation_ suppressClipboardContent];
 }
 
 void ClipboardRecentContentIOS::SaveToUserDefaults() {
-  [shared_user_defaults_ setInteger:last_pasteboard_change_count_
-                             forKey:kPasteboardChangeCountKey];
-  [shared_user_defaults_ setObject:last_pasteboard_change_date_
-                            forKey:kPasteboardChangeDateKey];
-  [shared_user_defaults_ setObject:last_pasteboard_entry_md5_
-                            forKey:kPasteboardEntryMD5Key];
+  [implementation_ saveToUserDefaults];
 }
 
-base::TimeDelta ClipboardRecentContentIOS::Uptime() const {
-  return base::SysInfo::Uptime();
+void ClipboardRecentContentIOS::SetLastPasteboardChangeDate(NSDate* date) {
+  [implementation_ setLastPasteboardChangeDate:date];
 }
+
+NSArray* ClipboardRecentContentIOS::GetAuthorizedSchemeList(

[sdefresne, 2017/04/03 09:27:16]

This can be a free function, no need to export this method as part of the class
API.

[lody, 2017/04/04 13:42:18]

Done.

+    const std::string& application_scheme) {
+  NSMutableArray* schemes = [NSMutableArray array];
+  for (size_t i = 0; i < arraysize(kAuthorizedSchemes); ++i) {
+    [schemes addObject:base::SysUTF8ToNSString(kAuthorizedSchemes[i])];
+  }
+  if (!application_scheme.empty()) {
+    [schemes addObject:base::SysUTF8ToNSString(application_scheme)];
+  }
+
+  return schemes;
+}