Implement chrome.input.ime.setComposition/commitText API.

chrome/browser/chromeos/input_method/input_method_engine.cc

 // Copyright 2013 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 "chrome/browser/chromeos/input_method/input_method_engine.h"
 
 #include <utility>
 
 #undef FocusIn
 #undef FocusOut
@@ skipping 35 matching lines @@
 
 namespace {
 
 const char kErrorNotActive[] = "IME is not active";
 const char kErrorWrongContext[] = "Context is not active";
 const char kCandidateNotFound[] = "Candidate not found";
 
 // The default entry number of a page in CandidateWindowProperty.
 const int kDefaultPageSize = 9;
 
+// Returns the length of characters of a UTF-8 string with unknown string
+// length. Cannot apply faster algorithm to count characters in an utf-8
+// string without knowing the string length,  so just does a full scan.
+size_t GetUtf8StringLength(const char* s) {

[Devlin, 2016/02/04 00:09:17]

Is this *really* that much faster than std::string(s).length()?  Is it in
extremely performance-sensitive code?  If not, let's avoid doing this (note that
it'd also be avoided if we can pass in a string to CommitTextToInputContext)

[Azure Wei, 2016/02/04 03:21:19]

Abandoned these codes.

+  size_t ret = 0;
+  while (*s) {
+    if ((*s & 0xC0) != 0x80)
+      ret++;
+    ++s;
+  }
+  return ret;
+}
+
 }  // namespace
 
 InputMethodEngine::MenuItem::MenuItem() {}
 
 InputMethodEngine::MenuItem::~MenuItem() {}
 
 InputMethodEngine::Candidate::Candidate() {}
 
 InputMethodEngine::Candidate::~Candidate() {}
 
@@ skipping 271 matching lines @@
         case MENU_ITEM_STYLE_SEPARATOR:
           // TODO(nona): Implement it.
           break;
       }
     }
   }
 
   // TODO(nona): Support item.children.
 }
 
+void InputMethodEngine::UpdateComposition(
+    const ui::CompositionText& composition_text,
+    uint32_t cursor_pos,
+    bool is_visible) {
+  ui::IMEInputContextHandlerInterface* input_context =
+      ui::IMEBridge::Get()->GetInputContextHandler();
+  if (input_context)
+    input_context->UpdateCompositionText(composition_text, cursor_pos,
+                                         is_visible);
+}
+
+void InputMethodEngine::CommitTextToInputContext(int context_id,
+                                                 const char* text) {
+  ui::IMEBridge::Get()->GetInputContextHandler()->CommitText(text);
+
+  // Records histograms for committed characters.
+  if (!composition_text_->text.empty()) {
+    size_t len = GetUtf8StringLength(text);
+    UMA_HISTOGRAM_CUSTOM_COUNTS("InputMethod.CommitLength", len, 1, 25, 25);
+    composition_text_.reset(new ui::CompositionText());
+  }
+}
+
 }  // namespace chromeos