Refactor Clipboard Last Modified Time Storage

ui/base/clipboard/clipboard_android.cc

Index: ui/base/clipboard/clipboard_android.cc
diff --git a/ui/base/clipboard/clipboard_android.cc b/ui/base/clipboard/clipboard_android.cc
index 8f35282acde0eb701fedebef5ec6aaaad0e84243..7e2fce29ccd1f0e38dd297e061abecb575ca8bba 100644
--- a/ui/base/clipboard/clipboard_android.cc
+++ b/ui/base/clipboard/clipboard_android.cc
@@ -8,10 +8,13 @@
 
 #include "base/android/context_utils.h"
 #include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
 #include "base/lazy_instance.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
+#include "base/time/time.h"
+#include "components/prefs/pref_registry_simple.h"
 #include "jni/Clipboard_jni.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/geometry/size.h"
@@ -37,6 +40,9 @@ using base::android::ScopedJavaLocalRef;
 namespace ui {
 
 namespace {
+
+const char kClipboardLastModifiedTimePref[] = "ui.clipboard.last_modified_time";
+
 // Various formats we support.
 const char kURLFormat[] = "url";
 const char kPlainTextFormat[] = "text";
@@ -50,18 +56,23 @@ class ClipboardMap {
  public:
   ClipboardMap();
   std::string Get(const std::string& format);
-  int64_t GetLastClipboardChangeTimeInMillis();
+  uint64_t GetSequenceNumber() const;
+  base::Time GetClipboardLastModifiedTime() const;
+  void ClearClipboardLastModifiedTime();

[dcheng, 2017/04/12 00:56:09]

Ditto: omit Clipboard in the names here.

[Mark P, 2017/04/12 21:33:51]

Done.

   bool HasFormat(const std::string& format);
+  void OnPrimaryClipboardChanged();
   void Set(const std::string& format, const std::string& data);
   void CommitToAndroidClipboard();
   void Clear();
 
  private:
   void UpdateFromAndroidClipboard();
+  void UpdateLastModifiedTimePref();
   std::map<std::string, std::string> map_;
   base::Lock lock_;
 
-  int64_t last_clipboard_change_time_ms_;
+  uint64_t sequence_number_;
+  base::Time clipboard_last_modified_time_;

[dcheng, 2017/04/12 00:56:09]

Nit: no clipboard_

[Mark P, 2017/04/12 21:33:51]

Done.

 
   // Java class and methods for the Android ClipboardManager.
   ScopedJavaGlobalRef<jobject> clipboard_manager_;
@@ -71,27 +82,44 @@ base::LazyInstance<ClipboardMap>::Leaky g_map = LAZY_INSTANCE_INITIALIZER;
 ClipboardMap::ClipboardMap() {
   clipboard_manager_.Reset(Java_Clipboard_getInstance(AttachCurrentThread()));
   DCHECK(clipboard_manager_.obj());
+  UpdateFromAndroidClipboard();
+  // ***
+  // Read |clipboard_last_modified_time_| as a time (in seconds) from prefs
+  // under name |kClipboardLastModifiedTimePref|.  Use 0 if the pref doesn't
+  // exist.
 }
 
 std::string ClipboardMap::Get(const std::string& format) {
   base::AutoLock lock(lock_);
-  UpdateFromAndroidClipboard();
   std::map<std::string, std::string>::const_iterator it = map_.find(format);
   return it == map_.end() ? std::string() : it->second;
 }
 
-int64_t ClipboardMap::GetLastClipboardChangeTimeInMillis() {
-  base::AutoLock lock(lock_);
-  UpdateFromAndroidClipboard();
-  return last_clipboard_change_time_ms_;
+uint64_t ClipboardMap::GetSequenceNumber() const {
+  return sequence_number_;
+}
+
+base::Time ClipboardMap::GetClipboardLastModifiedTime() const {
+  return clipboard_last_modified_time_;
+}
+
+void ClipboardMap::ClearClipboardLastModifiedTime() {
+  clipboard_last_modified_time_ = base::Time();
+  UpdateLastModifiedTimePref();
 }
 
 bool ClipboardMap::HasFormat(const std::string& format) {
   base::AutoLock lock(lock_);
-  UpdateFromAndroidClipboard();
   return base::ContainsKey(map_, format);
 }
 
+void ClipboardMap::OnPrimaryClipboardChanged() {
+  sequence_number_++;
+  clipboard_last_modified_time_ = base::Time::Now();
+  UpdateLastModifiedTimePref();
+  UpdateFromAndroidClipboard();

[dcheng, 2017/04/12 00:56:09]

I do wonder if we want to do this work up-front when the clipboard changes, or
just delay it to when the clipboard contents are actually read. The latter would
be a little more complex, but if we only invalidate here and don't repopulate
until data is actually read, that might be nicer from a performance perspective?

[Mark P, 2017/04/12 04:21:11]

Sure, I think I can do that pretty cleanly.
I'll make a bool |map_up_to_date|.

[Mark P, 2017/04/12 21:33:51]

Done.

+}
+
 void ClipboardMap::Set(const std::string& format, const std::string& data) {
   base::AutoLock lock(lock_);
   map_[format] = data;
@@ -122,6 +150,9 @@ void ClipboardMap::CommitToAndroidClipboard() {
     Java_Clipboard_clear(env, clipboard_manager_);
     NOTIMPLEMENTED();
   }
+  sequence_number_++;
+  clipboard_last_modified_time_ = base::Time::Now();
+  UpdateLastModifiedTimePref();
 }
 
 void ClipboardMap::Clear() {
@@ -129,6 +160,9 @@ void ClipboardMap::Clear() {
   base::AutoLock lock(lock_);
   map_.clear();
   Java_Clipboard_clear(env, clipboard_manager_);
+  sequence_number_++;
+  clipboard_last_modified_time_ = base::Time::Now();
+  UpdateLastModifiedTimePref();
 }
 
 // Add a key:jstr pair to map, but only if jstr is not null, and also
@@ -144,38 +178,25 @@ void AddMapEntry(JNIEnv* env,
   }
 }
 
-// Return true if all the key-value pairs in map1 are also in map2.
-bool MapIsSubset(const std::map<std::string, std::string>& map1,
-                 const std::map<std::string, std::string>& map2) {
-  for (const auto& val : map1) {
-    auto iter = map2.find(val.first);
-    if (iter == map2.end() || iter->second != val.second)
-      return false;
-  }
-  return true;
-}
-
 void ClipboardMap::UpdateFromAndroidClipboard() {
-  // Fetch the current Android clipboard state. Replace our state with
-  // the Android state if the Android state has been changed.
+  // Fetch the current Android clipboard state.
   lock_.AssertAcquired();
   JNIEnv* env = AttachCurrentThread();
 
-  std::map<std::string, std::string> android_clipboard_state;
-
   ScopedJavaLocalRef<jstring> jtext =
       Java_Clipboard_getCoercedText(env, clipboard_manager_);
   ScopedJavaLocalRef<jstring> jhtml =
       Java_Clipboard_getHTMLText(env, clipboard_manager_);
 
-  AddMapEntry(env, &android_clipboard_state, kPlainTextFormat, jtext);
-  AddMapEntry(env, &android_clipboard_state, kHTMLFormat, jhtml);
-  last_clipboard_change_time_ms_ =
-      Java_Clipboard_getClipboardContentChangeTimeInMillis(env,
-                                                           clipboard_manager_);
+  AddMapEntry(env, &map_, kPlainTextFormat, jtext);
+  AddMapEntry(env, &map_, kHTMLFormat, jhtml);
+}
 
-  if (!MapIsSubset(android_clipboard_state, map_))
-    android_clipboard_state.swap(map_);
+void ClipboardMap::UpdateLastModifiedTimePref() {
+  // ***
+  // Record |clipboard_last_modified_time_| as a time (in seconds) to prefs
+  // under name |kClipboardLastModifiedTimePref|.  Make sure that null times
+  // get recorded as 0.
 }
 
 }  // namespace
@@ -277,6 +298,18 @@ Clipboard* Clipboard::Create() {
 }
 
 // ClipboardAndroid implementation.
+
+// static
+void ClipboardAndroid::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterUint64Pref(kClipboardLastModifiedTimePref, 0u);
+}
+
+void ClipboardAndroid::OnPrimaryClipChanged(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  g_map.Get().OnPrimaryClipboardChanged();
+}
+
 ClipboardAndroid::ClipboardAndroid() {
   DCHECK(CalledOnValidThread());
 }
@@ -289,10 +322,7 @@ void ClipboardAndroid::OnPreShutdown() {}
 
 uint64_t ClipboardAndroid::GetSequenceNumber(ClipboardType /* type */) const {
   DCHECK(CalledOnValidThread());
-  // TODO: implement this. For now this interface will advertise
-  // that the clipboard never changes. That's fine as long as we
-  // don't rely on this signal.
-  return 0;
+  return g_map.Get().GetSequenceNumber();
 }
 
 bool ClipboardAndroid::IsFormatAvailable(const Clipboard::FormatType& format,
@@ -416,8 +446,12 @@ void ClipboardAndroid::ReadData(const Clipboard::FormatType& format,
 
 base::Time ClipboardAndroid::GetClipboardLastModifiedTime() const {
   DCHECK(CalledOnValidThread());
-  return base::Time::FromJavaTime(
-      g_map.Get().GetLastClipboardChangeTimeInMillis());
+  return g_map.Get().GetClipboardLastModifiedTime();
+}
+
+void ClipboardAndroid::ClearClipboardLastModifiedTime() {
+  DCHECK(CalledOnValidThread());
+  g_map.Get().ClearClipboardLastModifiedTime();
 }
 
 // Main entry point used to write several values in the clipboard.
@@ -485,4 +519,14 @@ void ClipboardAndroid::WriteData(const Clipboard::FormatType& format,
   g_map.Get().Set(format.ToString(), std::string(data_data, data_len));
 }
 
+bool RegisterClipboardAndroid(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+// Returns a pointer to the current ClipboardAndroid object.
+static jlong Init(JNIEnv* env,
+                  const base::android::JavaParamRef<jobject>& obj) {
+  return reinterpret_cast<intptr_t>(Clipboard::GetForCurrentThread());
+}
+
 } // namespace ui