cleanup the MappedFile API and comments. This removes and updates

tons of out of date comments (really nothing throws here!) and fixes
some other fairly glaring issues: "size" used to return the size of 
the file *and* change it, depending on how you called it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49009 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-04-01 00:53:25 +00:00
parent 328c84aa99
commit 540630f637
3 changed files with 158 additions and 212 deletions

View File

@ -28,145 +28,90 @@ namespace sys {
/// for mapping a file into memory for both read and write access. This class
/// does not provide facilities for finding the file or operating on paths to
/// files. The sys::Path class is used for that.
/// @since 1.4
/// @brief An abstraction for memory mapped files.
class MappedFile {
/// @name Types
/// @{
sys::PathWithStatus Path; ///< Path to the file.
unsigned Options; ///< Options used to create the mapping
void *BasePtr; ///< Pointer to the base memory address
mutable MappedFileInfo *MapInfo; ///< Platform specific info for the mapping
MappedFile& operator=(const MappedFile &that); // DO NOT IMPLEMENT
MappedFile(const MappedFile &that); // DO NOT IMPLEMENT
public:
enum MappingOptions {
READ_ACCESS = 0x0001, ///< Map the file for reading
WRITE_ACCESS = 0x0002, ///< Map the file for write access
EXEC_ACCESS = 0x0004, ///< Map the file for execution access
READ_ACCESS = 0x0001, ///< Map the file for reading
WRITE_ACCESS = 0x0002, ///< Map the file for write access
EXEC_ACCESS = 0x0004, ///< Map the file for execution access
SHARED_MAPPING = 0x0008 ///< Map the file shared with other processes
};
/// @}
/// @name Constructors
/// @{
public:
/// Construct a MappedFile to the \p path in the operating system's file
/// system with the mapping \p options provided.
/// @throws std::string if an error occurs
MappedFile() : path_(), options_(READ_ACCESS), base_(0), info_(0) {}
MappedFile() : Options(READ_ACCESS), BasePtr(0), MapInfo(0) {}
/// Destruct a MappedFile and release all memory associated with it.
/// @throws std::string if an error occurs
~MappedFile() { if (info_) terminate(); }
~MappedFile() { close(); }
public: // Accessors
/// @}
/// @name Accessors
/// @{
public:
/// This function determines if the file is currently mapped or not.
/// @returns true iff the file is mapped into memory, false otherwise
/// @brief Determine if a MappedFile is currently mapped
/// @throws nothing
bool isMapped() const { return base_ != 0; }
bool isMapped() const { return BasePtr != 0; }
/// This function returns a void* pointer to the base address of the file
/// mapping. This is the memory address of the first byte in the file.
/// Note that although a non-const pointer is returned, the memory might
/// not actually be writable, depending on the MappingOptions used when
/// the MappedFile was opened.
/// @returns The base pointer to the memory mapped file.
/// @brief Obtain the base pointer to the memory mapped file.
/// @throws nothing
void* base() const { return base_; }
void* base() const { return BasePtr; }
/// This function returns a char* pointer to the base address of the file
/// mapping. This is the memory address of the first byte in the file.
/// Note that although a non-const pointer is returned, the memory might
/// not actually be writable, depending on the MappingOptions used when
/// the MappedFile was opened.
/// @returns The base pointer to the memory mapped file as a char pointer.
/// @brief Obtain the base pointer to the memory mapped file.
/// @throws nothing
char* charBase() const { return reinterpret_cast<char*>(base_); }
char* charBase() const { return reinterpret_cast<char*>(BasePtr); }
/// This function returns a reference to the sys::Path object kept by the
/// MappedFile object. This contains the path to the file that is or
/// will be mapped.
/// @returns sys::Path containing the path name.
/// @brief Returns the mapped file's path as a sys::Path
/// @throws nothing
const sys::Path& path() const { return path_; }
const sys::Path& path() const { return Path; }
/// This function returns the number of bytes in the file.
/// @throws std::string if an error occurs
size_t size() const;
/// @}
/// @name Mutators
/// @{
public:
/// Open a file to be mapped and get its size but don't map it yet.
/// @returns true if an error occurred
bool open(
const sys::Path& p, ///< Path to file to be mapped
int options = READ_ACCESS, ///< Access mode for the mapping
std::string* ErrMsg = 0 ///< Optional error string pointer
) {
path_ = p;
options_ = options;
public: // Mutators
/// Open a file to be mapped and get its size but don't map it yet. Return
/// true on error.
bool open(const sys::Path &P, int options = READ_ACCESS,
std::string *ErrMsg = 0) {
Path = P;
Options = options;
return initialize(ErrMsg);
}
/// The mapped file is removed from memory. If the file was mapped for
/// unmap - Remove the mapped file from memory. If the file was mapped for
/// write access, the memory contents will be automatically synchronized
/// with the file's disk contents.
/// @brief Remove the file mapping from memory.
void unmap();
/// The mapped file is put into memory.
/// @returns The base memory address of the mapped file or 0 if an error
/// occurred.
/// @brief Map the file into memory.
void* map(
std::string* ErrMsg = 0///< Optional error string pointer
);
/// map - Reserve space for the file, map it into memory, and return a
/// pointer to it. This returns the base memory address of the mapped file
/// or 0 if an error occurred.
void *map(std::string* ErrMsg = 0);
/// This method causes the size of the file, and consequently the size
/// of the mapping to be set. This is logically the same as unmap(),
/// resize - This method causes the size of the file, and consequently the
/// size of the mapping to be set. This is logically the same as unmap(),
/// adjust size of the file, map(). Consequently, when calling this
/// function, the caller should not rely on previous results of the
/// map(), base(), or baseChar() members as they may point to invalid
/// areas of memory after this call.
/// @throws std::string if an error occurs
/// @brief Set the size of the file and memory mapping.
bool size(size_t new_size, std::string* ErrMsg = 0);
bool resize(size_t new_size, std::string *ErrMsg = 0);
void close() { if (info_) terminate(); }
void close() { if (MapInfo) terminate(); }
/// @}
/// @name Implementation
/// @{
private:
/// @brief Initialize platform-specific portion
bool initialize(std::string* ErrMsg);
/// @brief Terminate platform-specific portion
void terminate();
/// @}
/// @name Data
/// @{
private:
sys::PathWithStatus path_; ///< Path to the file.
int options_; ///< Options used to create the mapping
void* base_; ///< Pointer to the base memory address
mutable MappedFileInfo* info_; ///< Platform specific info for the mapping
/// @}
/// @name Disabled
/// @{
private:
///< Disallow assignment
MappedFile& operator=(const MappedFile &that);
///< Disallow copying
MappedFile(const MappedFile& that);
/// @}
bool initialize(std::string *ErrMsg);
void terminate();
};
}
}
} // end namespace sys
} // end namespace llvm
#endif

View File

@ -31,105 +31,109 @@
#include <sys/stat.h>
#endif
namespace llvm {
using namespace llvm;
using namespace sys;
struct sys::MappedFileInfo {
int FD;
off_t Size;
};
namespace llvm {
namespace sys {
struct MappedFileInfo {
int FD;
off_t Size;
};
}
}
bool MappedFile::initialize(std::string* ErrMsg) {
int mode = 0;
if (options_ & READ_ACCESS)
if (options_ & WRITE_ACCESS)
if (Options & READ_ACCESS)
if (Options & WRITE_ACCESS)
mode = O_RDWR;
else
mode = O_RDONLY;
else if (options_ & WRITE_ACCESS)
else if (Options & WRITE_ACCESS)
mode = O_WRONLY;
int FD = ::open(path_.c_str(), mode);
int FD = ::open(Path.c_str(), mode);
if (FD < 0) {
MakeErrMsg(ErrMsg, "can't open file '" + path_.toString() + "'");
MakeErrMsg(ErrMsg, "can't open file '" + Path.toString() + "'");
return true;
}
const FileStatus *Status = path_.getFileStatus(false, ErrMsg);
const FileStatus *Status = Path.getFileStatus(false, ErrMsg);
if (!Status) {
::close(FD);
return true;
}
info_ = new MappedFileInfo;
info_->FD = FD;
info_->Size = Status->getSize();
MapInfo = new MappedFileInfo();
MapInfo->FD = FD;
MapInfo->Size = Status->getSize();
return false;
}
void MappedFile::terminate() {
assert(info_ && "MappedFile not initialized");
::close(info_->FD);
delete info_;
info_ = 0;
assert(MapInfo && "MappedFile not initialized");
::close(MapInfo->FD);
delete MapInfo;
MapInfo = 0;
}
void MappedFile::unmap() {
assert(info_ && "MappedFile not initialized");
if (isMapped()) {
if (options_ & WRITE_ACCESS)
::msync(base_, info_->Size, MS_SYNC);
::munmap(base_, info_->Size);
base_ = 0; // Mark this as non-mapped.
}
assert(MapInfo && "MappedFile not initialized");
if (!isMapped()) return;
if (Options & WRITE_ACCESS)
::msync(BasePtr, MapInfo->Size, MS_SYNC);
::munmap(BasePtr, MapInfo->Size);
BasePtr = 0; // Mark this as non-mapped.
}
void* MappedFile::map(std::string* ErrMsg) {
assert(info_ && "MappedFile not initialized");
if (!isMapped()) {
int prot = PROT_NONE;
int flags = 0;
assert(MapInfo && "MappedFile not initialized");
if (isMapped()) return BasePtr;
int prot = PROT_NONE;
int flags = 0;
#ifdef MAP_FILE
flags |= MAP_FILE;
flags |= MAP_FILE;
#endif
if (options_ == 0) {
prot = PROT_READ;
flags = MAP_PRIVATE;
} else {
if (options_ & READ_ACCESS)
prot |= PROT_READ;
if (options_ & WRITE_ACCESS)
prot |= PROT_WRITE;
if (options_ & EXEC_ACCESS)
prot |= PROT_EXEC;
if (options_ & SHARED_MAPPING)
flags |= MAP_SHARED;
else
flags |= MAP_PRIVATE;
}
size_t map_size = ((info_->Size / Process::GetPageSize())+1) *
Process::GetPageSize();
base_ = ::mmap(0, map_size, prot, flags, info_->FD, 0);
if (base_ == MAP_FAILED) {
MakeErrMsg(ErrMsg, "Can't map file:" + path_.toString());
return 0;
}
if (Options == 0) {
prot = PROT_READ;
flags = MAP_PRIVATE;
} else {
if (Options & READ_ACCESS)
prot |= PROT_READ;
if (Options & WRITE_ACCESS)
prot |= PROT_WRITE;
if (Options & EXEC_ACCESS)
prot |= PROT_EXEC;
if (Options & SHARED_MAPPING)
flags |= MAP_SHARED;
else
flags |= MAP_PRIVATE;
}
return base_;
size_t map_size = ((MapInfo->Size / Process::GetPageSize())+1) *
Process::GetPageSize();
BasePtr = ::mmap(0, map_size, prot, flags, MapInfo->FD, 0);
if (BasePtr == MAP_FAILED) {
MakeErrMsg(ErrMsg, "Can't map file:" + Path.toString());
return 0;
}
return BasePtr;
}
size_t MappedFile::size() const {
assert(info_ && "MappedFile not initialized");
return info_->Size;
assert(MapInfo && "MappedFile not initialized");
return MapInfo->Size;
}
bool MappedFile::size(size_t new_size, std::string* ErrMsg) {
assert(info_ && "MappedFile not initialized");
bool MappedFile::resize(size_t new_size, std::string* ErrMsg) {
assert(MapInfo && "MappedFile not initialized");
// Take the mapping out of memory
this->unmap();
unmap();
// Adjust the current size to a page boundary
size_t cur_size = ((info_->Size / Process::GetPageSize())+1) *
size_t cur_size = ((MapInfo->Size / Process::GetPageSize())+1) *
Process::GetPageSize();
// Adjust the new_size to a page boundary
@ -140,15 +144,12 @@ bool MappedFile::size(size_t new_size, std::string* ErrMsg) {
if (new_size > cur_size) {
// Ensure we can allocate at least the idodes necessary to handle the
// file size requested.
if ((off_t)-1 == ::lseek(info_->FD, new_size, SEEK_SET))
if ((off_t)-1 == ::lseek(MapInfo->FD, new_size, SEEK_SET))
return MakeErrMsg(ErrMsg, "Can't lseek: ");
if (-1 == ::write(info_->FD, "\0", 1))
if (-1 == ::write(MapInfo->FD, "\0", 1))
return MakeErrMsg(ErrMsg, "Can't write: ");
}
// Put the mapping back into memory.
return this->map(ErrMsg);
return map(ErrMsg);
}
}

View File

@ -28,32 +28,32 @@ struct sys::MappedFileInfo {
};
bool MappedFile::initialize(std::string* ErrMsg) {
assert(!info_);
info_ = new MappedFileInfo;
info_->hFile = INVALID_HANDLE_VALUE;
info_->hMapping = NULL;
assert(!MapInfo);
MapInfo = new MappedFileInfo;
MapInfo->hFile = INVALID_HANDLE_VALUE;
MapInfo->hMapping = NULL;
DWORD mode = options_ & WRITE_ACCESS ? GENERIC_WRITE : GENERIC_READ;
DWORD disposition = options_ & WRITE_ACCESS ? OPEN_ALWAYS : OPEN_EXISTING;
DWORD share = options_ & WRITE_ACCESS ? FILE_SHARE_WRITE : FILE_SHARE_READ;
share = options_ & SHARED_MAPPING ? share : 0;
info_->hFile = CreateFile(path_.c_str(), mode, share, NULL, disposition,
DWORD mode = Options & WRITE_ACCESS ? GENERIC_WRITE : GENERIC_READ;
DWORD disposition = Options & WRITE_ACCESS ? OPEN_ALWAYS : OPEN_EXISTING;
DWORD share = Options & WRITE_ACCESS ? FILE_SHARE_WRITE : FILE_SHARE_READ;
share = Options & SHARED_MAPPING ? share : 0;
MapInfo->hFile = CreateFile(Path.c_str(), mode, share, NULL, disposition,
FILE_ATTRIBUTE_NORMAL, NULL);
if (info_->hFile == INVALID_HANDLE_VALUE) {
delete info_;
info_ = NULL;
if (MapInfo->hFile == INVALID_HANDLE_VALUE) {
delete MapInfo;
MapInfo = NULL;
return MakeErrMsg(ErrMsg,
std::string("Can't open file: ") + path_.toString());
std::string("Can't open file: ") + Path.toString());
}
LARGE_INTEGER size;
if (!GetFileSizeEx(info_->hFile, &size) ||
(info_->size = size_t(size.QuadPart), info_->size != size.QuadPart)) {
CloseHandle(info_->hFile);
delete info_;
info_ = NULL;
if (!GetFileSizeEx(MapInfo->hFile, &size) ||
(MapInfo->size = size_t(size.QuadPart), MapInfo->size != size.QuadPart)) {
CloseHandle(MapInfo->hFile);
delete MapInfo;
MapInfo = NULL;
return MakeErrMsg(ErrMsg,
std::string("Can't get size of file: ") + path_.toString());
std::string("Can't get size of file: ") + Path.toString());
}
return false;
@ -61,56 +61,56 @@ bool MappedFile::initialize(std::string* ErrMsg) {
void MappedFile::terminate() {
unmap();
if (info_->hFile != INVALID_HANDLE_VALUE)
CloseHandle(info_->hFile);
delete info_;
info_ = NULL;
if (MapInfo->hFile != INVALID_HANDLE_VALUE)
CloseHandle(MapInfo->hFile);
delete MapInfo;
MapInfo = NULL;
}
void MappedFile::unmap() {
assert(info_ && "MappedFile not initialized");
assert(MapInfo && "MappedFile not initialized");
if (isMapped()) {
UnmapViewOfFile(base_);
base_ = NULL;
UnmapViewOfFile(BasePtr);
BasePtr = NULL;
}
if (info_->hMapping != INVALID_HANDLE_VALUE) {
CloseHandle(info_->hMapping);
info_->hMapping = NULL;
if (MapInfo->hMapping != INVALID_HANDLE_VALUE) {
CloseHandle(MapInfo->hMapping);
MapInfo->hMapping = NULL;
}
}
void* MappedFile::map(std::string* ErrMsg) {
if (!isMapped()) {
DWORD prot = PAGE_READONLY;
if (options_ & EXEC_ACCESS)
if (Options & EXEC_ACCESS)
prot = SEC_IMAGE;
else if (options_ & WRITE_ACCESS)
else if (Options & WRITE_ACCESS)
prot = PAGE_READWRITE;
info_->hMapping = CreateFileMapping(info_->hFile, NULL, prot, 0, 0, NULL);
if (info_->hMapping == NULL) {
MakeErrMsg(ErrMsg, std::string("Can't map file: ") + path_.toString());
MapInfo->hMapping = CreateFileMapping(MapInfo->hFile, NULL, prot, 0, 0, NULL);
if (MapInfo->hMapping == NULL) {
MakeErrMsg(ErrMsg, std::string("Can't map file: ") + Path.toString());
return 0;
}
prot = (options_ & WRITE_ACCESS) ? FILE_MAP_WRITE : FILE_MAP_READ;
base_ = MapViewOfFileEx(info_->hMapping, prot, 0, 0, 0, NULL);
if (base_ == NULL) {
CloseHandle(info_->hMapping);
info_->hMapping = NULL;
MakeErrMsg(ErrMsg, std::string("Can't map file: ") + path_.toString());
prot = (Options & WRITE_ACCESS) ? FILE_MAP_WRITE : FILE_MAP_READ;
BasePtr = MapViewOfFileEx(MapInfo->hMapping, prot, 0, 0, 0, NULL);
if (BasePtr == NULL) {
CloseHandle(MapInfo->hMapping);
MapInfo->hMapping = NULL;
MakeErrMsg(ErrMsg, std::string("Can't map file: ") + Path.toString());
return 0;
}
}
return base_;
return BasePtr;
}
size_t MappedFile::size() const {
assert(info_ && "MappedFile not initialized");
return info_->size;
assert(MapInfo && "MappedFile not initialized");
return MapInfo->size;
}
bool MappedFile::size(size_t new_size, std::string* ErrMsg) {
assert(info_ && "MappedFile not initialized");
bool MappedFile::resize(size_t new_size, std::string* ErrMsg) {
assert(MapInfo && "MappedFile not initialized");
// Take the mapping out of memory.
unmap();
@ -120,16 +120,16 @@ bool MappedFile::size(size_t new_size, std::string* ErrMsg) {
new_size = (new_size + pagesizem1) & ~pagesizem1;
// If the file needs to be extended, do so.
if (new_size > info_->size) {
if (new_size > MapInfo->size) {
LARGE_INTEGER eof;
eof.QuadPart = new_size;
if (!SetFilePointerEx(info_->hFile, eof, NULL, FILE_BEGIN))
if (!SetFilePointerEx(MapInfo->hFile, eof, NULL, FILE_BEGIN))
return MakeErrMsg(ErrMsg,
std::string("Can't set end of file: ") + path_.toString());
if (!SetEndOfFile(info_->hFile))
std::string("Can't set end of file: ") + Path.toString());
if (!SetEndOfFile(MapInfo->hFile))
return MakeErrMsg(ErrMsg,
std::string("Can't set end of file: ") + path_.toString());
info_->size = new_size;
std::string("Can't set end of file: ") + Path.toString());
MapInfo->size = new_size;
}
// Remap the file.