Extract the rest of the mmap logic from the PCM provider. Closes #934.

This commit is contained in:
Thomas Goyne 2014-03-20 18:36:29 -07:00
parent 3222275750
commit 6c14c9bee9
4 changed files with 74 additions and 53 deletions

View file

@ -22,12 +22,17 @@
#include "libaegisub/util.h"
#include <boost/filesystem.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <limits>
#ifdef _WIN32
#include <Windows.h>
#endif
using namespace boost::interprocess;
namespace agi {
file_mapping::file_mapping(agi::fs::path const& filename, mode_t mode)
file_mapping::file_mapping(agi::fs::path const& filename, boost::interprocess::mode_t mode)
#ifdef _WIN32
: handle(CreateFileW(filename.wstring().c_str(), (unsigned int)mode, 0, nullptr, OPEN_EXISTING, 0, 0))
{
@ -63,4 +68,48 @@ file_mapping::~file_mapping() {
ipcdetail::close_file(handle);
}
}
read_file_mapping::read_file_mapping(fs::path const& filename)
: file(filename, read_only)
{
offset_t size;
ipcdetail::get_file_size(file.get_mapping_handle().handle, size);
file_size = static_cast<uint64_t>(size);
}
read_file_mapping::~read_file_mapping() { }
char *read_file_mapping::read(int64_t s_offset, uint64_t length) {
auto offset = static_cast<uint64_t>(s_offset);
if (offset + length > file_size)
throw InternalError("Attempted to map beyond end of file", nullptr);
// Check if we can just use the current mapping
if (region && offset >= mapping_start && offset + length <= mapping_start + region->get_size())
return static_cast<char *>(region->get_address()) + offset - mapping_start;
if (sizeof(size_t) == 4) {
mapping_start = offset & ~0xFFFFFULL; // Align to 1 MB bondary
length += static_cast<size_t>(offset - mapping_start);
// Map 16 MB or length rounded up to the next MB
length = std::min<uint64_t>(std::max<uint64_t>(0x1000000U, (length + 0xFFFFF) & ~0xFFFFF), file_size - mapping_start);
}
else {
// Just map the whole file
mapping_start = 0;
length = file_size;
}
if (length > std::numeric_limits<size_t>::max())
throw std::bad_alloc();
try {
region = agi::util::make_unique<mapped_region>(file, read_only, mapping_start, static_cast<size_t>(length));
}
catch (interprocess_exception const&) {
throw fs::FileSystemUnknownError("Failed mapping a view of the file");
}
return static_cast<char *>(region->get_address()) + offset - mapping_start;
}
}

View file

@ -17,6 +17,7 @@
#include <libaegisub/fs_fwd.h>
#include <boost/interprocess/detail/os_file_functions.hpp>
#include <cstdint>
namespace agi {
// boost::interprocess::file_mapping is awesome and uses CreateFileA on Windows
@ -30,4 +31,18 @@ namespace agi {
return boost::interprocess::ipcdetail::mapping_handle_from_file_handle(handle);
}
};
class read_file_mapping {
file_mapping file;
std::unique_ptr<boost::interprocess::mapped_region> region;
uint64_t mapping_start = 0;
uint64_t file_size = 0;
public:
read_file_mapping(fs::path const& filename);
~read_file_mapping();
uint64_t size() const { return file_size; }
char *read(int64_t offset, uint64_t length);
};
}

View file

@ -44,56 +44,21 @@
#include <libaegisub/log.h>
#include <libaegisub/util.h>
#include <boost/interprocess/file_mapping.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <cassert>
#include <cstdint>
using namespace boost::interprocess;
PCMAudioProvider::PCMAudioProvider(agi::fs::path const& filename)
: file(agi::util::make_unique<agi::file_mapping>(filename, read_only))
: file(agi::util::make_unique<agi::read_file_mapping>(filename))
{
float_samples = false;
try {
file_size = agi::fs::Size(filename);
}
catch (agi::Exception const& e) {
throw agi::AudioPlayerOpenError("Could not get file size", e.Copy());
}
}
PCMAudioProvider::~PCMAudioProvider() { }
char *PCMAudioProvider::EnsureRangeAccessible(int64_t start, int64_t length) const {
if (start + length > file_size)
throw AudioDecodeError("Attempted to map beyond end of file");
// Check if we can just use the current mapping
if (region && start >= mapping_start && start + length <= mapping_start + region->get_size())
return static_cast<char *>(region->get_address()) + start - mapping_start;
if (sizeof(size_t) == 4) {
mapping_start = start & ~0xFFFFFULL; // Align to 1 MB bondary
length += static_cast<size_t>(start - mapping_start);
// Map 16 MB or length rounded up to the next MB
length = std::min<size_t>(std::max<size_t>(0x1000000U, (length + 0xFFFFF) & ~0xFFFFF), file_size - mapping_start);
}
else {
// Just map the whole file
mapping_start = 0;
length = file_size;
}
try {
region = agi::util::make_unique<mapped_region>(*file, read_only, mapping_start, length);
return file->read(start, static_cast<size_t>(length));
}
catch (interprocess_exception const&) {
throw AudioDecodeError("Failed mapping a view of the file");
catch (agi::fs::FileSystemError const& e) {
throw AudioDecodeError(e.GetMessage());
}
return static_cast<char *>(region->get_address()) + start - mapping_start;
}
void PCMAudioProvider::FillBuffer(void *buf, int64_t start, int64_t count) const {
@ -322,15 +287,13 @@ public:
{
this->filename = filename;
int64_t smallest_possible_file = sizeof(RiffChunk) + sizeof(FormatChunk) + sizeof(DataChunk);
size_t smallest_possible_file = sizeof(RiffChunk) + sizeof(FormatChunk) + sizeof(DataChunk);
if (file_size < smallest_possible_file)
if (file->size() < smallest_possible_file)
throw agi::AudioDataNotFoundError("File is too small to be a Wave64 file", nullptr);
// Read header
// This should throw an exception if the mapping fails
void *filestart = EnsureRangeAccessible(0, sizeof(RiffChunk));
assert(filestart);
RiffChunk &header = *(RiffChunk*)filestart;
// Check magic values

View file

@ -32,22 +32,16 @@
#include <memory>
#include <vector>
namespace agi { class file_mapping; }
namespace boost { namespace interprocess { class mapped_region; } }
namespace agi { class read_file_mapping; }
class PCMAudioProvider : public AudioProvider {
std::unique_ptr<agi::file_mapping> file;
mutable std::unique_ptr<boost::interprocess::mapped_region> region;
mutable int64_t mapping_start = 0;
protected:
std::unique_ptr<agi::read_file_mapping> file;
PCMAudioProvider(agi::fs::path const& filename); // Create base object and open the file mapping
~PCMAudioProvider(); // Closes the file mapping
char *EnsureRangeAccessible(int64_t range_start, int64_t range_length) const; // Ensure that the given range of bytes are accessible in the file mapping and return a pointer to the first byte of the requested range
/// Size of the opened file
int64_t file_size = 0;
struct IndexPoint {
int64_t start_byte;
int64_t start_sample;