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//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MemoryBuffer interface.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
#define LLVM_SUPPORT_MEMORYBUFFER_H
#include "llvm-c/Types.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/CBindingWrapping.h"
#include "llvm/Support/ErrorOr.h"
#include <cstddef>
#include <cstdint>
#include <memory>
namespace llvm {
class MemoryBufferRef;
/// This interface provides simple read-only access to a block of memory, and
/// provides simple methods for reading files and standard input into a memory
/// buffer. In addition to basic access to the characters in the file, this
/// interface guarantees you can read one character past the end of the file,
/// and that this character will read as '\0'.
///
/// The '\0' guarantee is needed to support an optimization -- it's intended to
/// be more efficient for clients which are reading all the data to stop
/// reading when they encounter a '\0' than to continually check the file
/// position to see if it has reached the end of the file.
class MemoryBuffer {
const char *BufferStart; // Start of the buffer.
const char *BufferEnd; // End of the buffer.
protected:
MemoryBuffer() = default;
void init(const char *BufStart, const char *BufEnd,
bool RequiresNullTerminator);
public:
MemoryBuffer(const MemoryBuffer &) = delete;
MemoryBuffer &operator=(const MemoryBuffer &) = delete;
virtual ~MemoryBuffer();
const char *getBufferStart() const { return BufferStart; }
const char *getBufferEnd() const { return BufferEnd; }
size_t getBufferSize() const { return BufferEnd-BufferStart; }
StringRef getBuffer() const {
return StringRef(BufferStart, getBufferSize());
}
/// Return an identifier for this buffer, typically the filename it was read
/// from.
virtual StringRef getBufferIdentifier() const { return "Unknown buffer"; }
/// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
/// if successful, otherwise returning null. If FileSize is specified, this
/// means that the client knows that the file exists and that it has the
/// specified size.
///
/// \param IsVolatile Set to true to indicate that the contents of the file
/// can change outside the user's control, e.g. when libclang tries to parse
/// while the user is editing/updating the file or if the file is on an NFS.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFile(const Twine &Filename, int64_t FileSize = -1,
bool RequiresNullTerminator = true, bool IsVolatile = false);
/// Read all of the specified file into a MemoryBuffer as a stream
/// (i.e. until EOF reached). This is useful for special files that
/// look like a regular file but have 0 size (e.g. /proc/cpuinfo on Linux).
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileAsStream(const Twine &Filename);
/// Given an already-open file descriptor, map some slice of it into a
/// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
/// Since this is in the middle of a file, the buffer is not null terminated.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize,
int64_t Offset, bool IsVolatile = false);
/// Given an already-open file descriptor, read the file and return a
/// MemoryBuffer.
///
/// \param IsVolatile Set to true to indicate that the contents of the file
/// can change outside the user's control, e.g. when libclang tries to parse
/// while the user is editing/updating the file or if the file is on an NFS.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getOpenFile(int FD, const Twine &Filename, uint64_t FileSize,
bool RequiresNullTerminator = true, bool IsVolatile = false);
/// Open the specified memory range as a MemoryBuffer. Note that InputData
/// must be null terminated if RequiresNullTerminator is true.
static std::unique_ptr<MemoryBuffer>
getMemBuffer(StringRef InputData, StringRef BufferName = "",
bool RequiresNullTerminator = true);
static std::unique_ptr<MemoryBuffer>
getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
/// Open the specified memory range as a MemoryBuffer, copying the contents
/// and taking ownership of it. InputData does not have to be null terminated.
static std::unique_ptr<MemoryBuffer>
getMemBufferCopy(StringRef InputData, const Twine &BufferName = "");
/// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
/// that the caller need not initialize the memory allocated by this method.
/// The memory is owned by the MemoryBuffer object.
static std::unique_ptr<MemoryBuffer>
getNewMemBuffer(size_t Size, StringRef BufferName = "");
/// Allocate a new MemoryBuffer of the specified size that is not initialized.
/// Note that the caller should initialize the memory allocated by this
/// method. The memory is owned by the MemoryBuffer object.
static std::unique_ptr<MemoryBuffer>
getNewUninitMemBuffer(size_t Size, const Twine &BufferName = "");
/// Read all of stdin into a file buffer, and return it.
static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
/// Open the specified file as a MemoryBuffer, or open stdin if the Filename
/// is "-".
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1,
bool RequiresNullTerminator = true);
/// Map a subrange of the specified file as a MemoryBuffer.
static ErrorOr<std::unique_ptr<MemoryBuffer>>
getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
bool IsVolatile = false);
//===--------------------------------------------------------------------===//
// Provided for performance analysis.
//===--------------------------------------------------------------------===//
/// The kind of memory backing used to support the MemoryBuffer.
enum BufferKind {
MemoryBuffer_Malloc,
MemoryBuffer_MMap
};
/// Return information on the memory mechanism used to support the
/// MemoryBuffer.
virtual BufferKind getBufferKind() const = 0;
MemoryBufferRef getMemBufferRef() const;
};
class MemoryBufferRef {
StringRef Buffer;
StringRef Identifier;
public:
MemoryBufferRef() = default;
MemoryBufferRef(MemoryBuffer& Buffer)
: Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {}
MemoryBufferRef(StringRef Buffer, StringRef Identifier)
: Buffer(Buffer), Identifier(Identifier) {}
StringRef getBuffer() const { return Buffer; }
StringRef getBufferIdentifier() const { return Identifier; }
const char *getBufferStart() const { return Buffer.begin(); }
const char *getBufferEnd() const { return Buffer.end(); }
size_t getBufferSize() const { return Buffer.size(); }
};
// Create wrappers for C Binding types (see CBindingWrapping.h).
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
} // end namespace llvm
#endif // LLVM_SUPPORT_MEMORYBUFFER_H
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