blob: 726e2a72d59f3968c0c8db3d98a72aa7f3c31e4e (
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
131
132
133
134
|
#include "util/stream/rewindable_stream.hh"
#include "util/pcqueue.hh"
#include <iostream>
namespace util {
namespace stream {
RewindableStream::RewindableStream()
: current_(NULL), in_(NULL), out_(NULL), poisoned_(true) {
// nothing
}
void RewindableStream::Init(const ChainPosition &position) {
UTIL_THROW_IF2(in_, "RewindableStream::Init twice");
in_ = position.in_;
out_ = position.out_;
hit_poison_ = false;
poisoned_ = false;
progress_ = position.progress_;
entry_size_ = position.GetChain().EntrySize();
block_size_ = position.GetChain().BlockSize();
block_count_ = position.GetChain().BlockCount();
blocks_it_ = 0;
marked_ = NULL;
UTIL_THROW_IF2(block_count_ < 2, "RewindableStream needs block_count at least two");
AppendBlock();
}
RewindableStream &RewindableStream::operator++() {
assert(*this);
assert(current_ < block_end_);
assert(current_);
assert(blocks_it_ < blocks_.size());
current_ += entry_size_;
if (UTIL_UNLIKELY(current_ == block_end_)) {
// Fetch another block if necessary.
if (++blocks_it_ == blocks_.size()) {
if (!marked_) {
Flush(blocks_.begin() + blocks_it_);
blocks_it_ = 0;
}
AppendBlock();
assert(poisoned_ || (blocks_it_ == blocks_.size() - 1));
if (poisoned_) return *this;
}
Block &cur_block = blocks_[blocks_it_];
current_ = static_cast<uint8_t*>(cur_block.Get());
block_end_ = current_ + cur_block.ValidSize();
}
assert(current_);
assert(current_ >= static_cast<uint8_t*>(blocks_[blocks_it_].Get()));
assert(current_ < block_end_);
assert(block_end_ == blocks_[blocks_it_].ValidEnd());
return *this;
}
void RewindableStream::Mark() {
marked_ = current_;
Flush(blocks_.begin() + blocks_it_);
blocks_it_ = 0;
}
void RewindableStream::Rewind() {
if (current_ != marked_) {
poisoned_ = false;
}
blocks_it_ = 0;
current_ = marked_;
block_end_ = static_cast<const uint8_t*>(blocks_[blocks_it_].ValidEnd());
assert(current_);
assert(current_ >= static_cast<uint8_t*>(blocks_[blocks_it_].Get()));
assert(current_ < block_end_);
assert(block_end_ == blocks_[blocks_it_].ValidEnd());
}
void RewindableStream::Poison() {
if (blocks_.empty()) return;
assert(*this);
assert(blocks_it_ == blocks_.size() - 1);
// Produce all buffered blocks.
blocks_.back().SetValidSize(current_ - static_cast<uint8_t*>(blocks_.back().Get()));
Flush(blocks_.end());
blocks_it_ = 0;
Block poison;
if (!hit_poison_) {
in_->Consume(poison);
}
poison.SetToPoison();
out_->Produce(poison);
hit_poison_ = true;
poisoned_ = true;
}
void RewindableStream::AppendBlock() {
if (UTIL_UNLIKELY(blocks_.size() >= block_count_)) {
std::cerr << "RewindableStream trying to use more blocks than available" << std::endl;
abort();
}
if (UTIL_UNLIKELY(hit_poison_)) {
poisoned_ = true;
return;
}
Block get;
// The loop is needed since it is *feasible* that we're given 0 sized but
// valid blocks
do {
in_->Consume(get);
if (UTIL_LIKELY(get)) {
blocks_.push_back(get);
} else {
hit_poison_ = true;
poisoned_ = true;
return;
}
} while (UTIL_UNLIKELY(get.ValidSize() == 0));
current_ = static_cast<uint8_t*>(blocks_.back().Get());
block_end_ = static_cast<const uint8_t*>(blocks_.back().ValidEnd());
blocks_it_ = blocks_.size() - 1;
}
void RewindableStream::Flush(std::deque<Block>::iterator to) {
for (std::deque<Block>::iterator i = blocks_.begin(); i != to; ++i) {
out_->Produce(*i);
progress_ += i->ValidSize();
}
blocks_.erase(blocks_.begin(), to);
}
}
}
|
