Adding break iterator support to the i18n api extension....

src/extensions/experimental/break-iterator.cc

+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "break-iterator.h"
+
+#include "unicode/brkiter.h"
+#include "unicode/locid.h"
+#include "unicode/rbbi.h"
+
+namespace v8 {
+namespace internal {
+
+v8::Persistent<v8::FunctionTemplate> BreakIterator::break_iterator_template_;
+
+icu::BreakIterator* BreakIterator::UnpackBreakIterator(
+    v8::Handle<v8::Object> obj) {
+  if (break_iterator_template_->HasInstance(obj)) {
+    return static_cast<icu::BreakIterator*>(
+        obj->GetPointerFromInternalField(0));
+  }
+
+  return NULL;
+}
+
+void BreakIterator::DeleteBreakIterator(v8::Persistent<v8::Value> object,
+                                        void* param) {
+  v8::Persistent<v8::Object> persistent_object =
+      v8::Persistent<v8::Object>::Cast(object);
+
+  // First delete the hidden C++ object. Deleting NULL is ok.
+  delete UnpackBreakIterator(persistent_object);
+
+  // Then dispose of the persistent handle to JS object.
+  persistent_object.Dispose();
+}
+
+// Returns a ThrowException value in case we encounter invalid
+// object in UnpackBreakIterator method.
+static v8::Handle<v8::Value> ThrowUnexpectedObjectError() {
+  return v8::ThrowException(v8::Exception::Error(
+      v8::String::New("Internal - Unexpected object type.")));

[Mads Ager (chromium), 2011/03/01 09:10:14]

Might be nice to make the error message more informative? How about
"BreakIterator method called on an object that is not a BreakIterator".

[Nebojša Ćirić, 2011/03/01 17:15:15]

Done.

+}
+
+v8::Handle<v8::Value> BreakIterator::BreakIteratorAdoptText(
+    const v8::Arguments& args) {
+  if (args.Length() != 1 || !args[0]->IsString()) {
+    return v8::ThrowException(v8::Exception::SyntaxError(
+        v8::String::New("Text input is required.")));
+  }
+
+  icu::BreakIterator* break_iterator = UnpackBreakIterator(args.Holder());
+  if (!break_iterator) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  v8::Local<v8::String> text_value = args[0]->ToString();
+  UnicodeString text(*v8::String::Value(text_value),
+                     text_value->Length());
+
+  break_iterator->setText(text);
+
+  return v8::Undefined();
+}
+
+v8::Handle<v8::Value> BreakIterator::BreakIteratorFirst(
+    const v8::Arguments& args) {
+  icu::BreakIterator* break_iterator = UnpackBreakIterator(args.Holder());
+  if (!break_iterator) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  return v8::Int32::New(break_iterator->first());
+}
+
+v8::Handle<v8::Value> BreakIterator::BreakIteratorNext(
+    const v8::Arguments& args) {
+  icu::BreakIterator* break_iterator = UnpackBreakIterator(args.Holder());
+  if (!break_iterator) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  return v8::Int32::New(break_iterator->next());
+}
+
+v8::Handle<v8::Value> BreakIterator::BreakIteratorCurrent(
+    const v8::Arguments& args) {
+  icu::BreakIterator* break_iterator = UnpackBreakIterator(args.Holder());
+  if (!break_iterator) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  return v8::Int32::New(break_iterator->current());
+}
+
+v8::Handle<v8::Value> BreakIterator::BreakIteratorBreakType(
+    const v8::Arguments& args) {
+  icu::BreakIterator* break_iterator = UnpackBreakIterator(args.Holder());
+  if (!break_iterator) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  // TODO(cira): Remove cast once ICU fixes base BreakIterator class.
+  int32_t status =
+      static_cast<RuleBasedBreakIterator*>(break_iterator)->getRuleStatus();
+  // Keep return values in sync with JavaScript BreakType enum.
+  if (status >= UBRK_WORD_NONE && status < UBRK_WORD_NONE_LIMIT) {
+    return v8::Int32::New(UBRK_WORD_NONE);
+  } else if (status >= UBRK_WORD_NUMBER && status < UBRK_WORD_NUMBER_LIMIT) {
+    return v8::Int32::New(UBRK_WORD_NUMBER);
+  } else if (status >= UBRK_WORD_LETTER && status < UBRK_WORD_LETTER_LIMIT) {
+    return v8::Int32::New(UBRK_WORD_LETTER);
+  } else if (status >= UBRK_WORD_KANA && status < UBRK_WORD_KANA_LIMIT) {
+    return v8::Int32::New(UBRK_WORD_KANA);
+  } else if (status >= UBRK_WORD_IDEO && status < UBRK_WORD_IDEO_LIMIT) {
+    return v8::Int32::New(UBRK_WORD_IDEO);
+  } else {
+    return v8::Int32::New(-1);
+  }
+}
+
+v8::Handle<v8::Value> BreakIterator::JSBreakIterator(
+    const v8::Arguments& args) {
+  // No need to check args here, we do it in JavaScript.

[Mads Ager (chromium), 2011/03/01 09:10:14]

I actually think that you do want to check that the arguments are strings here
and throw an exception otherwise. In the JS code, you only check that the
arguments are not undefined. You can get arbitrary objects in here and
converting them to string does not necessarily succeed.

Consider the following JavaScript code:

var o = { valueOf: function() { throw 42; } };
var s = "" + o;

This will perform a ToString operation on 'o' which will result in an exception
being thrown. You can get in this situation for the two ToString calls here and
you do not deal with the exception case (where you will get a null handle back
from V8).

I think it is fine to not deal with it by checking that the two arguments are
strings before the conversion and throwing an exception otherwise.

[Nebojša Ćirić, 2011/03/01 17:15:15]

Done.

+  v8::HandleScope handle_scope;
+
+  const char* locale = *v8::String::Utf8Value(args[0]->ToString());
+  icu::Locale icu_locale(locale);
+
+  UErrorCode status = U_ZERO_ERROR;
+  icu::BreakIterator* break_iterator = NULL;
+  const char* type = *v8::String::Utf8Value(args[1]->ToString());
+  if (!strcmp(type, "character")) {
+    break_iterator =
+        icu::BreakIterator::createCharacterInstance(icu_locale, status);
+  } else if (!strcmp(type, "word")) {
+    break_iterator =
+        icu::BreakIterator::createWordInstance(icu_locale, status);
+  } else if (!strcmp(type, "sentence")) {
+    break_iterator =
+        icu::BreakIterator::createSentenceInstance(icu_locale, status);
+  } else if (!strcmp(type, "line")) {
+    break_iterator =
+        icu::BreakIterator::createLineInstance(icu_locale, status);
+  } else {
+    return v8::ThrowException(v8::Exception::SyntaxError(
+        v8::String::New("Invalid iterator type.")));
+  }
+
+  if (U_FAILURE(status)) {
+    delete break_iterator;
+    return v8::ThrowException(v8::Exception::Error(
+        v8::String::New("Failed to create break iterator.")));
+  }
+
+  if (break_iterator_template_.IsEmpty()) {
+    v8::Local<v8::FunctionTemplate> raw_template(v8::FunctionTemplate::New());
+
+    raw_template->SetClassName(v8::String::New("v8Locale.v8BreakIterator"));

[Mads Ager (chromium), 2011/03/01 09:10:14]

Maybe just v8BreakIterator?

[Nebojša Ćirić, 2011/03/01 17:15:15]

I did some testing yesterday before I decided on this name. If you do this:

Foo = function() {};
Foo.Bar = function() {};

var bar = new Foo.Bar();

Inspector in Chrome will show Foo.Bar for the type, not just Bar.

If you still think I should rename, I'll do it. 

On 2011/03/01 09:10:14, Mads Ager wrote:

+
+    // Define internal field count on instance template.
+    v8::Local<v8::ObjectTemplate> object_template =
+        raw_template->InstanceTemplate();
+    object_template->SetInternalFieldCount(1);
+
+    // Define all of the prototype methods on prototype template.
+    v8::Local<v8::ObjectTemplate> proto = raw_template->PrototypeTemplate();
+    proto->Set(v8::String::New("adoptText"),
+               v8::FunctionTemplate::New(BreakIteratorAdoptText));
+    proto->Set(v8::String::New("first"),
+               v8::FunctionTemplate::New(BreakIteratorFirst));
+    proto->Set(v8::String::New("next"),
+               v8::FunctionTemplate::New(BreakIteratorNext));
+    proto->Set(v8::String::New("current"),
+               v8::FunctionTemplate::New(BreakIteratorCurrent));
+    proto->Set(v8::String::New("breakType"),
+               v8::FunctionTemplate::New(BreakIteratorBreakType));
+
+    break_iterator_template_ =
+        v8::Persistent<v8::FunctionTemplate>::New(raw_template);
+  }
+
+  // Create an empty object wrapper.
+  v8::Local<v8::Object> local_object =
+      break_iterator_template_->GetFunction()->NewInstance();
+  v8::Persistent<v8::Object> wrapper =
+      v8::Persistent<v8::Object>::New(local_object);
+
+  // Set break iterator as internal field of the resulting JS object.
+  wrapper->SetPointerInInternalField(0, break_iterator);
+
+  // Make object handle weak so we can delete iterator once GC kicks in.
+  wrapper.MakeWeak(NULL, DeleteBreakIterator);
+
+  return wrapper;
+}
+
+} }  // namespace v8::internal