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/*
* Copyright (C) 2018 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.
*/
#ifndef ART_RUNTIME_INTERN_TABLE_INL_H_
#define ART_RUNTIME_INTERN_TABLE_INL_H_
#include "intern_table.h"
#include "dex/utf.h"
#include "gc/space/image_space.h"
#include "gc_root-inl.h"
#include "image.h"
#include "mirror/string-inl.h"
#include "thread-current-inl.h"
namespace art {
inline std::size_t InternTable::StringHash::operator()(const GcRoot<mirror::String>& root) const {
if (kIsDebugBuild) {
Locks::mutator_lock_->AssertSharedHeld(Thread::Current());
}
// An additional cast to prevent undesired sign extension.
return static_cast<size_t>(
static_cast<uint32_t>(root.Read<kWithoutReadBarrier>()->GetHashCode()));
}
inline bool InternTable::StringEquals::operator()(const GcRoot<mirror::String>& a,
const GcRoot<mirror::String>& b) const {
if (kIsDebugBuild) {
Locks::mutator_lock_->AssertSharedHeld(Thread::Current());
}
return a.Read<kWithoutReadBarrier>()->Equals(b.Read<kWithoutReadBarrier>());
}
inline bool InternTable::StringEquals::operator()(const GcRoot<mirror::String>& a,
const Utf8String& b) const {
if (kIsDebugBuild) {
Locks::mutator_lock_->AssertSharedHeld(Thread::Current());
}
ObjPtr<mirror::String> a_string = a.Read<kWithoutReadBarrier>();
uint32_t a_length = static_cast<uint32_t>(a_string->GetLength());
if (a_length != b.GetUtf16Length()) {
return false;
}
if (a_string->IsCompressed()) {
size_t b_byte_count = strlen(b.GetUtf8Data());
size_t b_utf8_length = CountModifiedUtf8Chars(b.GetUtf8Data(), b_byte_count);
// Modified UTF-8 single byte character range is 0x01 .. 0x7f
// The string compression occurs on regular ASCII with same exact range,
// not on extended ASCII which up to 0xff
const bool is_b_regular_ascii = (b_byte_count == b_utf8_length);
if (is_b_regular_ascii) {
return memcmp(b.GetUtf8Data(),
a_string->GetValueCompressed(), a_length * sizeof(uint8_t)) == 0;
} else {
return false;
}
} else {
const uint16_t* a_value = a_string->GetValue();
return CompareModifiedUtf8ToUtf16AsCodePointValues(b.GetUtf8Data(), a_value, a_length) == 0;
}
}
template <typename Visitor>
inline void InternTable::AddImageStringsToTable(gc::space::ImageSpace* image_space,
const Visitor& visitor) {
DCHECK(image_space != nullptr);
// Only add if we have the interned strings section.
const ImageHeader& header = image_space->GetImageHeader();
const ImageSection& section = header.GetInternedStringsSection();
if (section.Size() > 0) {
AddTableFromMemory(image_space->Begin() + section.Offset(), visitor, !header.IsAppImage());
}
}
template <typename Visitor>
inline size_t InternTable::AddTableFromMemory(const uint8_t* ptr,
const Visitor& visitor,
bool is_boot_image) {
size_t read_count = 0;
UnorderedSet set(ptr, /*make copy*/false, &read_count);
{
// Hold the lock while calling the visitor to prevent possible race
// conditions with another thread adding intern strings.
MutexLock mu(Thread::Current(), *Locks::intern_table_lock_);
// Visit the unordered set, may remove elements.
visitor(set);
if (!set.empty()) {
strong_interns_.AddInternStrings(std::move(set), is_boot_image);
}
}
return read_count;
}
inline void InternTable::Table::AddInternStrings(UnorderedSet&& intern_strings,
bool is_boot_image) {
static constexpr bool kCheckDuplicates = kIsDebugBuild;
if (kCheckDuplicates) {
// Avoid doing read barriers since the space might not yet be added to the heap.
// See b/117803941
for (GcRoot<mirror::String>& string : intern_strings) {
CHECK(Find(string.Read<kWithoutReadBarrier>()) == nullptr)
<< "Already found " << string.Read<kWithoutReadBarrier>()->ToModifiedUtf8()
<< " in the intern table";
}
}
// Insert at the front since we add new interns into the back.
tables_.insert(tables_.begin(),
InternalTable(std::move(intern_strings), is_boot_image));
}
template <typename Visitor>
inline void InternTable::VisitInterns(const Visitor& visitor,
bool visit_boot_images,
bool visit_non_boot_images) {
auto visit_tables = [&](std::vector<Table::InternalTable>& tables)
NO_THREAD_SAFETY_ANALYSIS {
for (Table::InternalTable& table : tables) {
// Determine if we want to visit the table based on the flags..
const bool visit =
(visit_boot_images && table.IsBootImage()) ||
(visit_non_boot_images && !table.IsBootImage());
if (visit) {
for (auto& intern : table.set_) {
visitor(intern);
}
}
}
};
visit_tables(strong_interns_.tables_);
visit_tables(weak_interns_.tables_);
}
inline size_t InternTable::CountInterns(bool visit_boot_images,
bool visit_non_boot_images) const {
size_t ret = 0u;
auto visit_tables = [&](const std::vector<Table::InternalTable>& tables)
NO_THREAD_SAFETY_ANALYSIS {
for (const Table::InternalTable& table : tables) {
// Determine if we want to visit the table based on the flags..
const bool visit =
(visit_boot_images && table.IsBootImage()) ||
(visit_non_boot_images && !table.IsBootImage());
if (visit) {
ret += table.set_.size();
}
}
};
visit_tables(strong_interns_.tables_);
visit_tables(weak_interns_.tables_);
return ret;
}
} // namespace art
#endif // ART_RUNTIME_INTERN_TABLE_INL_H_
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