blob: d9b130f3cac3d0d25dfd8072e347e4e5614fa1e7 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
// Copyright 2012 the V8 project 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 "src/v8.h"
#include "src/handles.h"
namespace v8 {
namespace internal {
int HandleScope::NumberOfHandles(Isolate* isolate) {
HandleScopeImplementer* impl = isolate->handle_scope_implementer();
int n = impl->blocks()->length();
if (n == 0) return 0;
return ((n - 1) * kHandleBlockSize) + static_cast<int>(
(isolate->handle_scope_data()->next - impl->blocks()->last()));
}
Object** HandleScope::Extend(Isolate* isolate) {
HandleScopeData* current = isolate->handle_scope_data();
Object** result = current->next;
DCHECK(result == current->limit);
// Make sure there's at least one scope on the stack and that the
// top of the scope stack isn't a barrier.
if (!Utils::ApiCheck(current->level != 0,
"v8::HandleScope::CreateHandle()",
"Cannot create a handle without a HandleScope")) {
return NULL;
}
HandleScopeImplementer* impl = isolate->handle_scope_implementer();
// If there's more room in the last block, we use that. This is used
// for fast creation of scopes after scope barriers.
if (!impl->blocks()->is_empty()) {
Object** limit = &impl->blocks()->last()[kHandleBlockSize];
if (current->limit != limit) {
current->limit = limit;
DCHECK(limit - current->next < kHandleBlockSize);
}
}
// If we still haven't found a slot for the handle, we extend the
// current handle scope by allocating a new handle block.
if (result == current->limit) {
// If there's a spare block, use it for growing the current scope.
result = impl->GetSpareOrNewBlock();
// Add the extension to the global list of blocks, but count the
// extension as part of the current scope.
impl->blocks()->Add(result);
current->limit = &result[kHandleBlockSize];
}
return result;
}
void HandleScope::DeleteExtensions(Isolate* isolate) {
HandleScopeData* current = isolate->handle_scope_data();
isolate->handle_scope_implementer()->DeleteExtensions(current->limit);
}
#ifdef ENABLE_HANDLE_ZAPPING
void HandleScope::ZapRange(Object** start, Object** end) {
DCHECK(end - start <= kHandleBlockSize);
for (Object** p = start; p != end; p++) {
*reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
}
}
#endif
Address HandleScope::current_level_address(Isolate* isolate) {
return reinterpret_cast<Address>(&isolate->handle_scope_data()->level);
}
Address HandleScope::current_next_address(Isolate* isolate) {
return reinterpret_cast<Address>(&isolate->handle_scope_data()->next);
}
Address HandleScope::current_limit_address(Isolate* isolate) {
return reinterpret_cast<Address>(&isolate->handle_scope_data()->limit);
}
DeferredHandleScope::DeferredHandleScope(Isolate* isolate)
: impl_(isolate->handle_scope_implementer()) {
impl_->BeginDeferredScope();
HandleScopeData* data = impl_->isolate()->handle_scope_data();
Object** new_next = impl_->GetSpareOrNewBlock();
Object** new_limit = &new_next[kHandleBlockSize];
DCHECK(data->limit == &impl_->blocks()->last()[kHandleBlockSize]);
impl_->blocks()->Add(new_next);
#ifdef DEBUG
prev_level_ = data->level;
#endif
data->level++;
prev_limit_ = data->limit;
prev_next_ = data->next;
data->next = new_next;
data->limit = new_limit;
}
DeferredHandleScope::~DeferredHandleScope() {
impl_->isolate()->handle_scope_data()->level--;
DCHECK(handles_detached_);
DCHECK(impl_->isolate()->handle_scope_data()->level == prev_level_);
}
DeferredHandles* DeferredHandleScope::Detach() {
DeferredHandles* deferred = impl_->Detach(prev_limit_);
HandleScopeData* data = impl_->isolate()->handle_scope_data();
data->next = prev_next_;
data->limit = prev_limit_;
#ifdef DEBUG
handles_detached_ = true;
#endif
return deferred;
}
} } // namespace v8::internal
|
