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refactor: simplify OS abstraction for mmap_block and fix move ops

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This commit is contained in:
Marcus Holland-Moritz 2025-04-15 09:58:33 +02:00
parent 6cf07409dc
commit b0bc9b20c4
1 changed files with 50 additions and 37 deletions
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87
src/reader/block_cache_byte_buffer_factory.cpp
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@ -44,60 +44,73 @@ namespace dwarfs::reader {
namespace {
#ifdef _WIN32
class mmap_block {
public:
mmap_block(size_t size)
: data_{::VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE)}
, size_{size} {
if (!data_) {
: data_{allocate(size)}
, size_{size} {}
mmap_block(mmap_block&& other) noexcept
: data_{other.data_}
, size_{other.size_} {
other.data_ = nullptr;
other.size_ = 0;
}
mmap_block& operator=(mmap_block&& other) noexcept {
if (this != &other) {
mmap_block tmp{std::move(*this)};
data_ = other.data_;
size_ = other.size_;
other.data_ = nullptr;
other.size_ = 0;
}
return *this;
}
size_t size() const { return size_; }
uint8_t* data() { return static_cast<uint8_t*>(data_); }
uint8_t const* data() const { return static_cast<uint8_t const*>(data_); }
~mmap_block() {
if (data_) {
deallocate(data_, size_);
}
}
private:
static void* allocate(size_t size) {
#ifdef _WIN32
void* data =
::VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
if (!data) {
std::error_code ec(::GetLastError(), std::system_category());
throw std::runtime_error("VirtualAlloc failed: " + ec.message());
}
}
size_t size() const { return size_; }
uint8_t* data() { return static_cast<uint8_t*>(data_); }
uint8_t const* data() const { return static_cast<uint8_t const*>(data_); }
~mmap_block() {
auto rv [[maybe_unused]] = ::VirtualFree(data_, 0, MEM_RELEASE);
assert(rv);
}
private:
void* data_;
size_t size_;
};
#else
class mmap_block {
public:
mmap_block(size_t size)
: data_{::mmap(nullptr, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)}
, size_{size} {
if (data_ == MAP_FAILED) {
void* data = ::mmap(nullptr, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (data == MAP_FAILED) {
throw std::runtime_error("mmap failed");
}
#endif
return data;
}
size_t size() const { return size_; }
uint8_t* data() { return static_cast<uint8_t*>(data_); }
uint8_t const* data() const { return static_cast<uint8_t const*>(data_); }
~mmap_block() {
auto rv [[maybe_unused]] = ::munmap(data_, size_);
static void deallocate(void* data, size_t size) {
#ifdef _WIN32
auto rv [[maybe_unused]] = ::VirtualFree(data, 0, MEM_RELEASE);
assert(rv);
#else
auto rv [[maybe_unused]] = ::munmap(data, size);
assert(rv == 0);
#endif
}
private:
void* data_;
size_t size_;
};
#endif
class mmap_byte_buffer_impl : public mutable_byte_buffer_interface {
public: