/*
* 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.
*/
#ifndef ART_RUNTIME_MIRROR_STRING_H_
#define ART_RUNTIME_MIRROR_STRING_H_
#include "base/bit_utils.h"
#include "gc/allocator_type.h"
#include "class.h"
#include "object.h"
#include "runtime_globals.h"
namespace art {
template<class T> class Handle;
template<class MirrorType> class ObjPtr;
struct StringOffsets;
class StubTest_ReadBarrierForRoot_Test;
namespace mirror {
// String Compression
static constexpr bool kUseStringCompression = true;
enum class StringCompressionFlag : uint32_t {
kCompressed = 0u,
kUncompressed = 1u
};
// C++ mirror of java.lang.String
class MANAGED String final : public Object {
public:
// Size of java.lang.String.class.
static uint32_t ClassSize(PointerSize pointer_size);
// Size of an instance of java.lang.String not including its value array.
static constexpr uint32_t InstanceSize() {
return sizeof(String);
}
static constexpr MemberOffset CountOffset() {
return OFFSET_OF_OBJECT_MEMBER(String, count_);
}
static constexpr MemberOffset ValueOffset() {
return OFFSET_OF_OBJECT_MEMBER(String, value_);
}
uint16_t* GetValue() REQUIRES_SHARED(Locks::mutator_lock_) {
return &value_[0];
}
uint8_t* GetValueCompressed() REQUIRES_SHARED(Locks::mutator_lock_) {
return &value_compressed_[0];
}
template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
size_t SizeOf() REQUIRES_SHARED(Locks::mutator_lock_) {
size_t size = sizeof(String);
if (IsCompressed()) {
size += (sizeof(uint8_t) * GetLength<kVerifyFlags>());
} else {
size += (sizeof(uint16_t) * GetLength<kVerifyFlags>());
}
// String.equals() intrinsics assume zero-padding up to kObjectAlignment,
// so make sure the zero-padding is actually copied around if GC compaction
// chooses to copy only SizeOf() bytes.
// http://b/23528461
return RoundUp(size, kObjectAlignment);
}
// Taking out the first/uppermost bit because it is not part of actual length value
template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
int32_t GetLength() REQUIRES_SHARED(Locks::mutator_lock_) {
return GetLengthFromCount(GetCount<kVerifyFlags>());
}
template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
int32_t GetCount() REQUIRES_SHARED(Locks::mutator_lock_) {
return GetField32<kVerifyFlags>(OFFSET_OF_OBJECT_MEMBER(String, count_));
}
void SetCount(int32_t new_count) REQUIRES_SHARED(Locks::mutator_lock_) {
// Count is invariant so use non-transactional mode. Also disable check as we may run inside
// a transaction.
SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(String, count_), new_count);
}
int32_t GetHashCode() REQUIRES_SHARED(Locks::mutator_lock_);
// Computes, stores, and returns the hash code.
int32_t ComputeHashCode() REQUIRES_SHARED(Locks::mutator_lock_);
int32_t GetUtfLength() REQUIRES_SHARED(Locks::mutator_lock_);
uint16_t CharAt(int32_t index) REQUIRES_SHARED(Locks::mutator_lock_);
// Create a new string where all occurences of `old_c` are replaced with `new_c`.
// String.doReplace(char, char) is called from String.replace(char, char) when there is a match.
static ObjPtr<String> DoReplace(Thread* self, Handle<String> src, uint16_t old_c, uint16_t new_c)
REQUIRES_SHARED(Locks::mutator_lock_);
ObjPtr<String> Intern() REQUIRES_SHARED(Locks::mutator_lock_);
template <bool kIsInstrumented>
ALWAYS_INLINE static ObjPtr<String> AllocFromByteArray(Thread* self,
int32_t byte_length,
Handle<ByteArray> array,
int32_t offset,
int32_t high_byte,
gc::AllocatorType allocator_type)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
template <bool kIsInstrumented>
ALWAYS_INLINE static ObjPtr<String> AllocFromCharArray(Thread* self,
int32_t count,
Handle<CharArray> array,
int32_t offset,
gc::AllocatorType allocator_type)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
template <bool kIsInstrumented>
ALWAYS_INLINE static ObjPtr<String> AllocFromString(Thread* self,
int32_t string_length,
Handle<String> string,
int32_t offset,
gc::AllocatorType allocator_type)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
template <bool kIsInstrumented>
ALWAYS_INLINE static ObjPtr<String> AllocEmptyString(Thread* self,
gc::AllocatorType allocator_type)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
static ObjPtr<String> AllocFromStrings(Thread* self,
Handle<String> string,
Handle<String> string2)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
static ObjPtr<String> AllocFromUtf16(Thread* self,
int32_t utf16_length,
const uint16_t* utf16_data_in)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
static ObjPtr<String> AllocFromModifiedUtf8(Thread* self, const char* utf)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
static ObjPtr<String> AllocFromModifiedUtf8(Thread* self,
int32_t utf16_length,
const char* utf8_data_in,
int32_t utf8_length)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
static ObjPtr<String> AllocFromModifiedUtf8(Thread* self,
int32_t utf16_length,
const char* utf8_data_in)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
bool Equals(const char* modified_utf8) REQUIRES_SHARED(Locks::mutator_lock_);
bool Equals(ObjPtr<String> that) REQUIRES_SHARED(Locks::mutator_lock_);
// Create a modified UTF-8 encoded std::string from a java/lang/String object.
std::string ToModifiedUtf8() REQUIRES_SHARED(Locks::mutator_lock_);
int32_t FastIndexOf(int32_t ch, int32_t start) REQUIRES_SHARED(Locks::mutator_lock_);
template <typename MemoryType>
int32_t FastIndexOf(MemoryType* chars, int32_t ch, int32_t start)
REQUIRES_SHARED(Locks::mutator_lock_);
int32_t CompareTo(ObjPtr<String> other) REQUIRES_SHARED(Locks::mutator_lock_);
ObjPtr<CharArray> ToCharArray(Thread* self) REQUIRES_SHARED(Locks::mutator_lock_)
REQUIRES(!Roles::uninterruptible_);
void GetChars(int32_t start, int32_t end, Handle<CharArray> array, int32_t index)
REQUIRES_SHARED(Locks::mutator_lock_);
template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
bool IsCompressed() REQUIRES_SHARED(Locks::mutator_lock_) {
return kUseStringCompression && IsCompressed(GetCount());
}
bool IsValueNull() REQUIRES_SHARED(Locks::mutator_lock_);
template<typename MemoryType>
static bool AllASCII(const MemoryType* chars, const int length);
static bool DexFileStringAllASCII(const char* chars, const int length);
ALWAYS_INLINE static bool IsCompressed(int32_t count) {
return GetCompressionFlagFromCount(count) == StringCompressionFlag::kCompressed;
}
ALWAYS_INLINE static StringCompressionFlag GetCompressionFlagFromCount(int32_t count) {
return kUseStringCompression
? static_cast<StringCompressionFlag>(static_cast<uint32_t>(count) & 1u)
: StringCompressionFlag::kUncompressed;
}
ALWAYS_INLINE static int32_t GetLengthFromCount(int32_t count) {
return kUseStringCompression ? static_cast<int32_t>(static_cast<uint32_t>(count) >> 1) : count;
}
ALWAYS_INLINE static int32_t GetFlaggedCount(int32_t length, bool compressible) {
return kUseStringCompression
? static_cast<int32_t>((static_cast<uint32_t>(length) << 1) |
(static_cast<uint32_t>(compressible
? StringCompressionFlag::kCompressed
: StringCompressionFlag::kUncompressed)))
: length;
}
// Returns a human-readable equivalent of 'descriptor'. So "I" would be "int",
// "[[I" would be "int[][]", "[Ljava/lang/String;" would be
// "java.lang.String[]", and so forth.
static std::string PrettyStringDescriptor(ObjPtr<mirror::String> descriptor)
REQUIRES_SHARED(Locks::mutator_lock_);
std::string PrettyStringDescriptor()
REQUIRES_SHARED(Locks::mutator_lock_);
private:
static constexpr bool IsASCII(uint16_t c) {
// Valid ASCII characters are in range 1..0x7f. Zero is not considered ASCII
// because it would complicate the detection of ASCII strings in Modified-UTF8.
return (c - 1u) < 0x7fu;
}
static bool AllASCIIExcept(const uint16_t* chars, int32_t length, uint16_t non_ascii);
void SetHashCode(int32_t new_hash_code) REQUIRES_SHARED(Locks::mutator_lock_) {
// Hash code is invariant so use non-transactional mode. Also disable check as we may run inside
// a transaction.
DCHECK_EQ(0, GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_)));
SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(String, hash_code_), new_hash_code);
}
template <bool kIsInstrumented, typename PreFenceVisitor>
ALWAYS_INLINE static ObjPtr<String> Alloc(Thread* self,
int32_t utf16_length_with_flag,
gc::AllocatorType allocator_type,
const PreFenceVisitor& pre_fence_visitor)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
// Field order required by test "ValidateFieldOrderOfJavaCppUnionClasses".
// If string compression is enabled, count_ holds the StringCompressionFlag in the
// least significant bit and the length in the remaining bits, length = count_ >> 1.
int32_t count_;
uint32_t hash_code_;
// Compression of all-ASCII into 8-bit memory leads to usage one of these fields
union {
uint16_t value_[0];
uint8_t value_compressed_[0];
};
friend struct art::StringOffsets; // for verifying offset information
DISALLOW_IMPLICIT_CONSTRUCTORS(String);
};
} // namespace mirror
} // namespace art
#endif // ART_RUNTIME_MIRROR_STRING_H_