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- // Copyright (c) 2011 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 "base/i18n/break_iterator.h"
- #include <stdint.h>
- #include <ostream>
- #include "base/check.h"
- #include "base/lazy_instance.h"
- #include "base/memory/raw_ptr.h"
- #include "base/notreached.h"
- #include "base/synchronization/lock.h"
- #include "third_party/icu/source/common/unicode/ubrk.h"
- #include "third_party/icu/source/common/unicode/uchar.h"
- #include "third_party/icu/source/common/unicode/ustring.h"
- namespace base {
- namespace i18n {
- const size_t npos = static_cast<size_t>(-1);
- BreakIterator::BreakIterator(const StringPiece16& str, BreakType break_type)
- : iter_(nullptr),
- string_(str),
- break_type_(break_type),
- prev_(npos),
- pos_(0) {}
- BreakIterator::BreakIterator(const StringPiece16& str,
- const std::u16string& rules)
- : iter_(nullptr),
- string_(str),
- rules_(rules),
- break_type_(RULE_BASED),
- prev_(npos),
- pos_(0) {}
- namespace {
- // We found the usage pattern of break iterator is to create, use and destroy.
- // The following cache support multiple break iterator in the same thread and
- // also optimize to not create break iterator many time. For each kind of break
- // iterator (character, word, line and sentence, but NOT rule), we keep one of
- // them in the main_ and lease it out. If some other code request a lease
- // before |main_| is returned, we create a new instance of the iterator.
- // This will keep at most 4 break iterators (one for each kind) unreleased until
- // the program destruction time.
- template <UBreakIteratorType break_type>
- class DefaultLocaleBreakIteratorCache {
- public:
- DefaultLocaleBreakIteratorCache()
- : main_status_(U_ZERO_ERROR),
- main_(nullptr),
- main_could_be_leased_(true) {
- main_ = ubrk_open(break_type, nullptr, nullptr, 0, &main_status_);
- if (U_FAILURE(main_status_)) {
- NOTREACHED() << "ubrk_open failed for type " << break_type
- << " with error " << main_status_;
- }
- }
- virtual ~DefaultLocaleBreakIteratorCache() { ubrk_close(main_); }
- UBreakIterator* Lease(UErrorCode& status) {
- if (U_FAILURE(status)) {
- return nullptr;
- }
- if (U_FAILURE(main_status_)) {
- status = main_status_;
- return nullptr;
- }
- {
- AutoLock scoped_lock(lock_);
- if (main_could_be_leased_) {
- // Just lease the main_ out.
- main_could_be_leased_ = false;
- return main_;
- }
- }
- // The main_ is already leased out to some other places, return a new
- // object instead.
- UBreakIterator* result =
- ubrk_open(break_type, nullptr, nullptr, 0, &status);
- if (U_FAILURE(status)) {
- NOTREACHED() << "ubrk_open failed for type " << break_type
- << " with error " << status;
- }
- return result;
- }
- void Return(UBreakIterator* item) {
- // If the return item is the main_, just remember we can lease it out
- // next time.
- if (item == main_) {
- AutoLock scoped_lock(lock_);
- main_could_be_leased_ = true;
- } else {
- // Close the item if it is not main_.
- ubrk_close(item);
- }
- }
- private:
- UErrorCode main_status_;
- raw_ptr<UBreakIterator> main_;
- bool main_could_be_leased_ GUARDED_BY(lock_);
- Lock lock_;
- };
- static LazyInstance<DefaultLocaleBreakIteratorCache<UBRK_CHARACTER>>::Leaky
- char_break_cache = LAZY_INSTANCE_INITIALIZER;
- static LazyInstance<DefaultLocaleBreakIteratorCache<UBRK_WORD>>::Leaky
- word_break_cache = LAZY_INSTANCE_INITIALIZER;
- static LazyInstance<DefaultLocaleBreakIteratorCache<UBRK_SENTENCE>>::Leaky
- sentence_break_cache = LAZY_INSTANCE_INITIALIZER;
- static LazyInstance<DefaultLocaleBreakIteratorCache<UBRK_LINE>>::Leaky
- line_break_cache = LAZY_INSTANCE_INITIALIZER;
- } // namespace
- BreakIterator::~BreakIterator() {
- if (iter_) {
- UBreakIterator* iter = static_cast<UBreakIterator*>(iter_);
- switch (break_type_) {
- // Free the iter if it is RULE_BASED
- case RULE_BASED:
- ubrk_close(iter);
- break;
- // Otherwise, return the iter to the cache it leased from.`
- case BREAK_CHARACTER:
- char_break_cache.Pointer()->Return(iter);
- break;
- case BREAK_WORD:
- word_break_cache.Pointer()->Return(iter);
- break;
- case BREAK_SENTENCE:
- sentence_break_cache.Pointer()->Return(iter);
- break;
- case BREAK_LINE:
- case BREAK_NEWLINE:
- line_break_cache.Pointer()->Return(iter);
- break;
- default:
- NOTREACHED() << "invalid break_type_";
- break;
- }
- }
- }
- bool BreakIterator::Init() {
- UErrorCode status = U_ZERO_ERROR;
- UParseError parse_error;
- switch (break_type_) {
- case BREAK_CHARACTER:
- iter_ = char_break_cache.Pointer()->Lease(status);
- break;
- case BREAK_WORD:
- iter_ = word_break_cache.Pointer()->Lease(status);
- break;
- case BREAK_SENTENCE:
- iter_ = sentence_break_cache.Pointer()->Lease(status);
- break;
- case BREAK_LINE:
- case BREAK_NEWLINE:
- iter_ = line_break_cache.Pointer()->Lease(status);
- break;
- case RULE_BASED:
- iter_ =
- ubrk_openRules(rules_.c_str(), static_cast<int32_t>(rules_.length()),
- nullptr, 0, &parse_error, &status);
- if (U_FAILURE(status)) {
- NOTREACHED() << "ubrk_openRules failed to parse rule string at line "
- << parse_error.line << ", offset " << parse_error.offset;
- }
- break;
- default:
- NOTREACHED() << "invalid break_type_";
- return false;
- }
- if (U_FAILURE(status) || iter_ == nullptr) {
- return false;
- }
- if (string_.data() != nullptr) {
- ubrk_setText(static_cast<UBreakIterator*>(iter_), string_.data(),
- static_cast<int32_t>(string_.size()), &status);
- if (U_FAILURE(status)) {
- return false;
- }
- }
- // Move the iterator to the beginning of the string.
- ubrk_first(static_cast<UBreakIterator*>(iter_));
- return true;
- }
- bool BreakIterator::Advance() {
- int32_t pos;
- int32_t status;
- prev_ = pos_;
- switch (break_type_) {
- case BREAK_CHARACTER:
- case BREAK_WORD:
- case BREAK_LINE:
- case BREAK_SENTENCE:
- case RULE_BASED:
- pos = ubrk_next(static_cast<UBreakIterator*>(iter_));
- if (pos == UBRK_DONE) {
- pos_ = npos;
- return false;
- }
- pos_ = static_cast<size_t>(pos);
- return true;
- case BREAK_NEWLINE:
- do {
- pos = ubrk_next(static_cast<UBreakIterator*>(iter_));
- if (pos == UBRK_DONE)
- break;
- pos_ = static_cast<size_t>(pos);
- status = ubrk_getRuleStatus(static_cast<UBreakIterator*>(iter_));
- } while (status >= UBRK_LINE_SOFT && status < UBRK_LINE_SOFT_LIMIT);
- if (pos == UBRK_DONE && prev_ == pos_) {
- pos_ = npos;
- return false;
- }
- return true;
- default:
- NOTREACHED() << "invalid break_type_";
- return false;
- }
- }
- bool BreakIterator::SetText(const char16_t* text, const size_t length) {
- UErrorCode status = U_ZERO_ERROR;
- ubrk_setText(static_cast<UBreakIterator*>(iter_), text, length, &status);
- pos_ = 0; // implicit when ubrk_setText is done
- prev_ = npos;
- if (U_FAILURE(status)) {
- NOTREACHED() << "ubrk_setText failed";
- return false;
- }
- string_ = StringPiece16(text, length);
- return true;
- }
- bool BreakIterator::IsWord() const {
- return GetWordBreakStatus() == IS_WORD_BREAK;
- }
- BreakIterator::WordBreakStatus BreakIterator::GetWordBreakStatus() const {
- int32_t status = ubrk_getRuleStatus(static_cast<UBreakIterator*>(iter_));
- if (break_type_ != BREAK_WORD && break_type_ != RULE_BASED)
- return IS_LINE_OR_CHAR_BREAK;
- // In ICU 60, trying to advance past the end of the text does not change
- // |status| so that |pos_| has to be checked as well as |status|.
- // See http://bugs.icu-project.org/trac/ticket/13447 .
- return (status == UBRK_WORD_NONE || pos_ == npos) ? IS_SKIPPABLE_WORD
- : IS_WORD_BREAK;
- }
- bool BreakIterator::IsEndOfWord(size_t position) const {
- if (break_type_ != BREAK_WORD && break_type_ != RULE_BASED)
- return false;
- UBreakIterator* iter = static_cast<UBreakIterator*>(iter_);
- UBool boundary = ubrk_isBoundary(iter, static_cast<int32_t>(position));
- int32_t status = ubrk_getRuleStatus(iter);
- return (!!boundary && status != UBRK_WORD_NONE);
- }
- bool BreakIterator::IsStartOfWord(size_t position) const {
- if (break_type_ != BREAK_WORD && break_type_ != RULE_BASED)
- return false;
- UBreakIterator* iter = static_cast<UBreakIterator*>(iter_);
- UBool boundary = ubrk_isBoundary(iter, static_cast<int32_t>(position));
- ubrk_next(iter);
- int32_t next_status = ubrk_getRuleStatus(iter);
- return (!!boundary && next_status != UBRK_WORD_NONE);
- }
- bool BreakIterator::IsSentenceBoundary(size_t position) const {
- if (break_type_ != BREAK_SENTENCE && break_type_ != RULE_BASED)
- return false;
- UBreakIterator* iter = static_cast<UBreakIterator*>(iter_);
- return !!ubrk_isBoundary(iter, static_cast<int32_t>(position));
- }
- bool BreakIterator::IsGraphemeBoundary(size_t position) const {
- if (break_type_ != BREAK_CHARACTER)
- return false;
- UBreakIterator* iter = static_cast<UBreakIterator*>(iter_);
- return !!ubrk_isBoundary(iter, static_cast<int32_t>(position));
- }
- std::u16string BreakIterator::GetString() const {
- return std::u16string(GetStringPiece());
- }
- StringPiece16 BreakIterator::GetStringPiece() const {
- DCHECK(prev_ != npos && pos_ != npos);
- return string_.substr(prev_, pos_ - prev_);
- }
- } // namespace i18n
- } // namespace base
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