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_impl_ios.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 {
 
-// Initialize the ApplicationDidBecomeActiveNotificationListenerBridge with
-// |delegate| which must not be null.
-- (instancetype)initWithDelegate:(ClipboardRecentContentIOS*)delegate
-    NS_DESIGNATED_INITIALIZER;
+// Schemes accepted by the ClipboardRecentContentIOS.
+const char* kAuthorizedSchemes[] = {
+    url::kHttpScheme, url::kHttpsScheme, url::kDataScheme, url::kAboutScheme,
+};
 
-- (instancetype)init NS_UNAVAILABLE;
+// Get the list of authorized schemes.
+NSSet<NSString*>* getAuthorizedSchemeList(
+    const std::string& application_scheme) {
+  NSMutableSet<NSString*>* schemes = [NSMutableSet set];
+  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 copy];
+}
+
+}  // namespace
+
+@interface ClipboardRecentContentDelegateImpl
+    : NSObject<ClipboardRecentContentDelegate>
 @end
 
-@implementation ApplicationDidBecomeActiveNotificationListenerBridge {
-  ClipboardRecentContentIOS* _delegate;
-}
+@implementation ClipboardRecentContentDelegateImpl
 
-- (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"));
 }
 
 @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";
+ClipboardRecentContentIOS::ClipboardRecentContentIOS(
+    const std::string& application_scheme,
+    NSUserDefaults* group_user_defaults)
+    : ClipboardRecentContentIOS([[ClipboardRecentContentImplIOS alloc]
+          initWithAuthorizedSchemes:getAuthorizedSchemeList(application_scheme)
+                       userDefaults:group_user_defaults
+                           delegate:[[ClipboardRecentContentDelegateImpl 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;
+ClipboardRecentContentIOS::ClipboardRecentContentIOS(
+    ClipboardRecentContentImplIOS* implementation) {
+  implementation_.reset(implementation);
 }
 
-}  // 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;
+  NSURL* url_from_pasteboard = [implementation_ recentURLFromClipboard];
+  GURL converted_url = net::GURLWithNSURL(url_from_pasteboard);
+  if (converted_url.is_valid()) {
+    *url = std::move(converted_url);
     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_ clipboardContentAge]));
 }
 
 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();
+  [implementation_ suppressClipboardContent];
 }
-
-void ClipboardRecentContentIOS::UpdateIfNeeded() {
-  if (!HasPasteboardChanged())
-    return;
-
-  base::RecordAction(base::UserMetricsAction("MobileClipboardChanged"));
-
-  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()) {
-    if (IsAppropriateSuggestion(gurl))
-      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]]);
-}
-
-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];
-}
-
-base::TimeDelta ClipboardRecentContentIOS::Uptime() const {
-  return base::SysInfo::Uptime();
-}