jni_env_ext.cc revision 90443477f9a0061581c420775ce3b7eeae7468bc 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "jni_env_ext.h"
18
19#include "check_jni.h"
20#include "indirect_reference_table.h"
21#include "java_vm_ext.h"
22#include "jni_internal.h"
23
24namespace art {
25
26static constexpr size_t kMonitorsInitial = 32;  // Arbitrary.
27static constexpr size_t kMonitorsMax = 4096;  // Arbitrary sanity check.
28
29static constexpr size_t kLocalsInitial = 64;  // Arbitrary.
30
31// Checking "locals" requires the mutator lock, but at creation time we're really only interested
32// in validity, which isn't changing. To avoid grabbing the mutator lock, factored out and tagged
33// with NO_THREAD_SAFETY_ANALYSIS.
34static bool CheckLocalsValid(JNIEnvExt* in) NO_THREAD_SAFETY_ANALYSIS {
35  if (in == nullptr) {
36    return false;
37  }
38  return in->locals.IsValid();
39}
40
41JNIEnvExt* JNIEnvExt::Create(Thread* self_in, JavaVMExt* vm_in) {
42  std::unique_ptr<JNIEnvExt> ret(new JNIEnvExt(self_in, vm_in));
43  if (CheckLocalsValid(ret.get())) {
44    return ret.release();
45  }
46  return nullptr;
47}
48
49JNIEnvExt::JNIEnvExt(Thread* self_in, JavaVMExt* vm_in)
50    : self(self_in),
51      vm(vm_in),
52      local_ref_cookie(IRT_FIRST_SEGMENT),
53      locals(kLocalsInitial, kLocalsMax, kLocal, false),
54      check_jni(false),
55      critical(0),
56      monitors("monitors", kMonitorsInitial, kMonitorsMax) {
57  functions = unchecked_functions = GetJniNativeInterface();
58  if (vm->IsCheckJniEnabled()) {
59    SetCheckJniEnabled(true);
60  }
61}
62
63JNIEnvExt::~JNIEnvExt() {
64}
65
66jobject JNIEnvExt::NewLocalRef(mirror::Object* obj) SHARED_REQUIRES(Locks::mutator_lock_) {
67  if (obj == nullptr) {
68    return nullptr;
69  }
70  return reinterpret_cast<jobject>(locals.Add(local_ref_cookie, obj));
71}
72
73void JNIEnvExt::DeleteLocalRef(jobject obj) SHARED_REQUIRES(Locks::mutator_lock_) {
74  if (obj != nullptr) {
75    locals.Remove(local_ref_cookie, reinterpret_cast<IndirectRef>(obj));
76  }
77}
78
79void JNIEnvExt::SetCheckJniEnabled(bool enabled) {
80  check_jni = enabled;
81  functions = enabled ? GetCheckJniNativeInterface() : GetJniNativeInterface();
82}
83
84void JNIEnvExt::DumpReferenceTables(std::ostream& os) {
85  locals.Dump(os);
86  monitors.Dump(os);
87}
88
89void JNIEnvExt::PushFrame(int capacity) SHARED_REQUIRES(Locks::mutator_lock_) {
90  UNUSED(capacity);  // cpplint gets confused with (int) and thinks its a cast.
91  // TODO: take 'capacity' into account.
92  stacked_local_ref_cookies.push_back(local_ref_cookie);
93  local_ref_cookie = locals.GetSegmentState();
94}
95
96void JNIEnvExt::PopFrame() SHARED_REQUIRES(Locks::mutator_lock_) {
97  locals.SetSegmentState(local_ref_cookie);
98  local_ref_cookie = stacked_local_ref_cookies.back();
99  stacked_local_ref_cookies.pop_back();
100}
101
102Offset JNIEnvExt::SegmentStateOffset() {
103  return Offset(OFFSETOF_MEMBER(JNIEnvExt, locals) +
104                IndirectReferenceTable::SegmentStateOffset().Int32Value());
105}
106
107}  // namespace art
108