1 //===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the MemoryBuffer interface.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SUPPORT_MEMORYBUFFER_H
15 #define LLVM_SUPPORT_MEMORYBUFFER_H
17 #include "llvm-c/Support.h"
18 #include "llvm/ADT/Twine.h"
19 #include "llvm/Support/CBindingWrapping.h"
20 #include "llvm/Support/Compiler.h"
21 #include "llvm/Support/DataTypes.h"
23 #include <system_error>
26 /// MemoryBuffer - This interface provides simple read-only access to a block
27 /// of memory, and provides simple methods for reading files and standard input
28 /// into a memory buffer. In addition to basic access to the characters in the
29 /// file, this interface guarantees you can read one character past the end of
30 /// the file, and that this character will read as '\0'.
32 /// The '\0' guarantee is needed to support an optimization -- it's intended to
33 /// be more efficient for clients which are reading all the data to stop
34 /// reading when they encounter a '\0' than to continually check the file
35 /// position to see if it has reached the end of the file.
37 const char *BufferStart; // Start of the buffer.
38 const char *BufferEnd; // End of the buffer.
40 MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
41 MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
44 void init(const char *BufStart, const char *BufEnd,
45 bool RequiresNullTerminator);
47 virtual ~MemoryBuffer();
49 const char *getBufferStart() const { return BufferStart; }
50 const char *getBufferEnd() const { return BufferEnd; }
51 size_t getBufferSize() const { return BufferEnd-BufferStart; }
53 StringRef getBuffer() const {
54 return StringRef(BufferStart, getBufferSize());
57 /// getBufferIdentifier - Return an identifier for this buffer, typically the
58 /// filename it was read from.
59 virtual const char *getBufferIdentifier() const {
60 return "Unknown buffer";
63 /// getFile - Open the specified file as a MemoryBuffer, returning a new
64 /// MemoryBuffer if successful, otherwise returning null. If FileSize is
65 /// specified, this means that the client knows that the file exists and that
66 /// it has the specified size.
68 /// \param IsVolatileSize Set to true to indicate that the file size may be
69 /// changing, e.g. when libclang tries to parse while the user is
70 /// editing/updating the file.
71 static std::error_code getFile(Twine Filename,
72 std::unique_ptr<MemoryBuffer> &Result,
73 int64_t FileSize = -1,
74 bool RequiresNullTerminator = true,
75 bool IsVolatileSize = false);
77 /// Given an already-open file descriptor, map some slice of it into a
78 /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
79 /// Since this is in the middle of a file, the buffer is not null terminated.
81 /// \param IsVolatileSize Set to true to indicate that the file size may be
82 /// changing, e.g. when libclang tries to parse while the user is
83 /// editing/updating the file.
84 static std::error_code getOpenFileSlice(int FD, const char *Filename,
85 std::unique_ptr<MemoryBuffer> &Result,
86 uint64_t MapSize, int64_t Offset,
87 bool IsVolatileSize = false);
89 /// Given an already-open file descriptor, read the file and return a
92 /// \param IsVolatileSize Set to true to indicate that the file size may be
93 /// changing, e.g. when libclang tries to parse while the user is
94 /// editing/updating the file.
95 static std::error_code getOpenFile(int FD, const char *Filename,
96 std::unique_ptr<MemoryBuffer> &Result,
98 bool RequiresNullTerminator = true,
99 bool IsVolatileSize = false);
101 /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
102 /// that InputData must be null terminated if RequiresNullTerminator is true.
103 static MemoryBuffer *getMemBuffer(StringRef InputData,
104 StringRef BufferName = "",
105 bool RequiresNullTerminator = true);
107 /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
108 /// copying the contents and taking ownership of it. InputData does not
109 /// have to be null terminated.
110 static MemoryBuffer *getMemBufferCopy(StringRef InputData,
111 StringRef BufferName = "");
113 /// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
114 /// is completely initialized to zeros. Note that the caller should
115 /// initialize the memory allocated by this method. The memory is owned by
116 /// the MemoryBuffer object.
117 static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
119 /// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
120 /// that is not initialized. Note that the caller should initialize the
121 /// memory allocated by this method. The memory is owned by the MemoryBuffer
123 static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
124 StringRef BufferName = "");
126 /// getSTDIN - Read all of stdin into a file buffer, and return it.
127 /// If an error occurs, this returns null and sets ec.
128 static std::error_code getSTDIN(std::unique_ptr<MemoryBuffer> &Result);
130 /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
131 /// if the Filename is "-". If an error occurs, this returns null and sets
133 static std::error_code getFileOrSTDIN(StringRef Filename,
134 std::unique_ptr<MemoryBuffer> &Result,
135 int64_t FileSize = -1);
137 //===--------------------------------------------------------------------===//
138 // Provided for performance analysis.
139 //===--------------------------------------------------------------------===//
141 /// The kind of memory backing used to support the MemoryBuffer.
147 /// Return information on the memory mechanism used to support the
149 virtual BufferKind getBufferKind() const = 0;
152 // Create wrappers for C Binding types (see CBindingWrapping.h).
153 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
155 } // end namespace llvm