size_t extend(size - before);
void *data(mmap(NULL, extend, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, file_, before));
+ _assert(data != MAP_FAILED);
uint8_t *bytes(reinterpret_cast<uint8_t *>(data));
- maps_.push_back(Mapping_(bytes,extend));
+ maps_.push_back(Mapping_(bytes, extend));
for (size_t i(0); i != extend >> Shift_; ++i)
blocks_.push_back(bytes + Block_ * i);
}
- void Truncate_(size_t capacity) {
+ bool Truncate_(size_t capacity) {
capacity = Round(capacity, Block_);
- ftruncate(file_, capacity);
+
+ int error(ftruncate(file_, capacity));
+ if (error != 0)
+ return false;
+
Map_(capacity);
+ return true;
}
public:
void Open(const char *path) {
_assert(file_ == -1);
file_ = open(path, O_RDWR | O_CREAT | O_EXLOCK, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+ _assert(file_ != -1);
struct stat stat;
- fstat(file_, &stat);
+ _assert(fstat(file_, &stat) == 0);
size_t core(sizeof(Header) + sizeof(Base_));
size_t size(stat.st_size);
if (size == 0) {
- Truncate_(core);
+ _assert(Truncate_(core));
Header_().magic_ = Magic;
Size_() = core;
} else {
_assert(size >= core);
- Truncate_(size);
+ // XXX: this involves an unneccessary call to ftruncate()
+ _assert(Truncate_(size));
_assert(Header_().magic_ == Magic);
_assert(Header_().version_ == 0);
}
}
- void Reserve(size_t capacity) {
+ bool Reserve(size_t capacity) {
if (capacity <= Capacity())
- return;
+ return true;
+
+ uint8_t *block(blocks_.back());
blocks_.pop_back();
- Truncate_(capacity);
+
+ if (Truncate_(capacity))
+ return true;
+ else {
+ blocks_.push_back(block);
+ return false;
+ }
}
template <typename Target_>
Target_ &Get(uint32_t offset) {
- return *reinterpret_cast<Target_ *>(blocks_[offset >> Shift_] + (offset & Mask_));
+ return *reinterpret_cast<Target_ *>(offset == 0 ? NULL : blocks_[offset >> Shift_] + (offset & Mask_));
}
template <typename Target_>
Offset<Target_> New(size_t extra = 0) {
size_t size(sizeof(Target_) + extra);
size = Round(size, sizeof(uintptr_t));
- Reserve(Size_() + size);
- uint32_t offset(Size_());
- Size_() += size;
+
+ uint32_t offset;
+ if (!Reserve(Size_() + size))
+ offset = 0;
+ else {
+ offset = Size_();
+ Size_() += size;
+ }
+
return Offset<Target_>(offset);
}
};