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 using std::error_code;
27 /// MemoryBuffer - This interface provides simple read-only access to a block
28 /// of memory, and provides simple methods for reading files and standard input
29 /// into a memory buffer. In addition to basic access to the characters in the
30 /// file, this interface guarantees you can read one character past the end of
31 /// the file, and that this character will read as '\0'.
33 /// The '\0' guarantee is needed to support an optimization -- it's intended to
34 /// be more efficient for clients which are reading all the data to stop
35 /// reading when they encounter a '\0' than to continually check the file
36 /// position to see if it has reached the end of the file.
38 const char *BufferStart; // Start of the buffer.
39 const char *BufferEnd; // End of the buffer.
41 MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
42 MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
45 void init(const char *BufStart, const char *BufEnd,
46 bool RequiresNullTerminator);
48 virtual ~MemoryBuffer();
50 const char *getBufferStart() const { return BufferStart; }
51 const char *getBufferEnd() const { return BufferEnd; }
52 size_t getBufferSize() const { return BufferEnd-BufferStart; }
54 StringRef getBuffer() const {
55 return StringRef(BufferStart, getBufferSize());
58 /// getBufferIdentifier - Return an identifier for this buffer, typically the
59 /// filename it was read from.
60 virtual const char *getBufferIdentifier() const {
61 return "Unknown buffer";
64 /// getFile - Open the specified file as a MemoryBuffer, returning a new
65 /// MemoryBuffer if successful, otherwise returning null. If FileSize is
66 /// specified, this means that the client knows that the file exists and that
67 /// it has the specified size.
69 /// \param IsVolatileSize Set to true to indicate that the file size may be
70 /// changing, e.g. when libclang tries to parse while the user is
71 /// editing/updating the file.
72 static error_code getFile(Twine Filename,
73 std::unique_ptr<MemoryBuffer> &Result,
74 int64_t FileSize = -1,
75 bool RequiresNullTerminator = true,
76 bool IsVolatileSize = false);
78 /// Given an already-open file descriptor, map some slice of it into a
79 /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
80 /// Since this is in the middle of a file, the buffer is not null terminated.
82 /// \param IsVolatileSize Set to true to indicate that the file size may be
83 /// changing, e.g. when libclang tries to parse while the user is
84 /// editing/updating the file.
85 static error_code getOpenFileSlice(int FD, const char *Filename,
86 std::unique_ptr<MemoryBuffer> &Result,
87 uint64_t MapSize, int64_t Offset,
88 bool IsVolatileSize = false);
90 /// Given an already-open file descriptor, read the file and return a
93 /// \param IsVolatileSize Set to true to indicate that the file size may be
94 /// changing, e.g. when libclang tries to parse while the user is
95 /// editing/updating the file.
96 static error_code getOpenFile(int FD, const char *Filename,
97 std::unique_ptr<MemoryBuffer> &Result,
99 bool RequiresNullTerminator = true,
100 bool IsVolatileSize = false);
102 /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
103 /// that InputData must be null terminated if RequiresNullTerminator is true.
104 static MemoryBuffer *getMemBuffer(StringRef InputData,
105 StringRef BufferName = "",
106 bool RequiresNullTerminator = true);
108 /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
109 /// copying the contents and taking ownership of it. InputData does not
110 /// have to be null terminated.
111 static MemoryBuffer *getMemBufferCopy(StringRef InputData,
112 StringRef BufferName = "");
114 /// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
115 /// is completely initialized to zeros. Note that the caller should
116 /// initialize the memory allocated by this method. The memory is owned by
117 /// the MemoryBuffer object.
118 static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
120 /// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
121 /// that is not initialized. Note that the caller should initialize the
122 /// memory allocated by this method. The memory is owned by the MemoryBuffer
124 static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
125 StringRef BufferName = "");
127 /// getSTDIN - Read all of stdin into a file buffer, and return it.
128 /// If an error occurs, this returns null and sets ec.
129 static error_code getSTDIN(std::unique_ptr<MemoryBuffer> &Result);
132 /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
133 /// if the Filename is "-". If an error occurs, this returns null and sets
135 static error_code getFileOrSTDIN(StringRef Filename,
136 std::unique_ptr<MemoryBuffer> &Result,
137 int64_t FileSize = -1);
139 //===--------------------------------------------------------------------===//
140 // Provided for performance analysis.
141 //===--------------------------------------------------------------------===//
143 /// The kind of memory backing used to support the MemoryBuffer.
149 /// Return information on the memory mechanism used to support the
151 virtual BufferKind getBufferKind() const = 0;
154 // Create wrappers for C Binding types (see CBindingWrapping.h).
155 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
157 } // end namespace llvm