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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "intern_table.h"
#include "mirror/string.h"
#include "thread.h"
#include "UniquePtr.h"
#include "utf.h"
namespace art {
InternTable::InternTable() : intern_table_lock_("InternTable lock"), is_dirty_(false) {
}
size_t InternTable::Size() const {
MutexLock mu(Thread::Current(), intern_table_lock_);
return strong_interns_.size() + weak_interns_.size();
}
void InternTable::DumpForSigQuit(std::ostream& os) const {
MutexLock mu(Thread::Current(), intern_table_lock_);
os << "Intern table: " << strong_interns_.size() << " strong; "
<< weak_interns_.size() << " weak; "
<< image_strong_interns_.size() << " image strong\n";
}
void InternTable::VisitRoots(RootVisitor* visitor, void* arg, bool clean_dirty) {
MutexLock mu(Thread::Current(), intern_table_lock_);
for (const auto& strong_intern : strong_interns_) {
visitor(strong_intern.second, arg);
}
if (clean_dirty) {
is_dirty_ = false;
}
// Note: we deliberately don't visit the weak_interns_ table and the immutable image roots.
}
mirror::String* InternTable::Lookup(Table& table, mirror::String* s, uint32_t hash_code) {
intern_table_lock_.AssertHeld(Thread::Current());
for (auto it = table.find(hash_code), end = table.end(); it != end; ++it) {
mirror::String* existing_string = it->second;
if (existing_string->Equals(s)) {
return existing_string;
}
}
return NULL;
}
mirror::String* InternTable::Insert(Table& table, mirror::String* s, uint32_t hash_code) {
intern_table_lock_.AssertHeld(Thread::Current());
table.insert(std::make_pair(hash_code, s));
return s;
}
void InternTable::RegisterStrong(mirror::String* s) {
MutexLock mu(Thread::Current(), intern_table_lock_);
Insert(image_strong_interns_, s, s->GetHashCode());
}
void InternTable::Remove(Table& table, const mirror::String* s, uint32_t hash_code) {
intern_table_lock_.AssertHeld(Thread::Current());
for (auto it = table.find(hash_code), end = table.end(); it != end; ++it) {
if (it->second == s) {
table.erase(it);
return;
}
}
}
mirror::String* InternTable::Insert(mirror::String* s, bool is_strong) {
MutexLock mu(Thread::Current(), intern_table_lock_);
DCHECK(s != NULL);
uint32_t hash_code = s->GetHashCode();
if (is_strong) {
// Check the strong table for a match.
mirror::String* strong = Lookup(strong_interns_, s, hash_code);
if (strong != NULL) {
return strong;
}
// Check the image table for a match.
mirror::String* image = Lookup(image_strong_interns_, s, hash_code);
if (image != NULL) {
return image;
}
// Mark as dirty so that we rescan the roots.
Dirty();
// There is no match in the strong table, check the weak table.
mirror::String* weak = Lookup(weak_interns_, s, hash_code);
if (weak != NULL) {
// A match was found in the weak table. Promote to the strong table.
Remove(weak_interns_, weak, hash_code);
return Insert(strong_interns_, weak, hash_code);
}
// No match in the strong table or the weak table. Insert into the strong table.
return Insert(strong_interns_, s, hash_code);
}
// Check the strong table for a match.
mirror::String* strong = Lookup(strong_interns_, s, hash_code);
if (strong != NULL) {
return strong;
}
// Check the image table for a match.
mirror::String* image = Lookup(image_strong_interns_, s, hash_code);
if (image != NULL) {
return image;
}
// Check the weak table for a match.
mirror::String* weak = Lookup(weak_interns_, s, hash_code);
if (weak != NULL) {
return weak;
}
// Insert into the weak table.
return Insert(weak_interns_, s, hash_code);
}
mirror::String* InternTable::InternStrong(int32_t utf16_length, const char* utf8_data) {
return InternStrong(mirror::String::AllocFromModifiedUtf8(Thread::Current(), utf16_length, utf8_data));
}
mirror::String* InternTable::InternStrong(const char* utf8_data) {
return InternStrong(mirror::String::AllocFromModifiedUtf8(Thread::Current(), utf8_data));
}
mirror::String* InternTable::InternStrong(mirror::String* s) {
if (s == NULL) {
return NULL;
}
return Insert(s, true);
}
mirror::String* InternTable::InternWeak(mirror::String* s) {
if (s == NULL) {
return NULL;
}
return Insert(s, false);
}
bool InternTable::ContainsWeak(mirror::String* s) {
MutexLock mu(Thread::Current(), intern_table_lock_);
const mirror::String* found = Lookup(weak_interns_, s, s->GetHashCode());
return found == s;
}
void InternTable::SweepInternTableWeaks(IsMarkedTester is_marked, void* arg) {
MutexLock mu(Thread::Current(), intern_table_lock_);
// TODO: std::remove_if + lambda.
for (auto it = weak_interns_.begin(), end = weak_interns_.end(); it != end;) {
mirror::Object* object = it->second;
if (!is_marked(object, arg)) {
weak_interns_.erase(it++);
} else {
++it;
}
}
}
} // namespace art
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