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/ADT/Twine.h"
18 #include "llvm/Support/CBindingWrapping.h"
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/Support/ErrorOr.h"
24 class MemoryBufferRef;
26 /// This interface provides simple read-only access to a block of memory, and
27 /// provides simple methods for reading files and standard input into a memory
28 /// buffer. In addition to basic access to the characters in the file, this
29 /// interface guarantees you can read one character past the end of the file,
30 /// 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 &) = delete;
41 MemoryBuffer &operator=(const MemoryBuffer &) = delete;
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 /// Return an identifier for this buffer, typically the filename it was read
59 virtual const char *getBufferIdentifier() const {
60 return "Unknown buffer";
63 /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
64 /// if successful, otherwise returning null. If FileSize is specified, this
65 /// means that the client knows that the file exists and that it has the
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 ErrorOr<std::unique_ptr<MemoryBuffer>>
72 getFile(const Twine &Filename, int64_t FileSize = -1,
73 bool RequiresNullTerminator = true, bool IsVolatileSize = false);
75 /// Given an already-open file descriptor, map some slice of it into a
76 /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
77 /// Since this is in the middle of a file, the buffer is not null terminated.
78 static ErrorOr<std::unique_ptr<MemoryBuffer>>
79 getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize,
82 /// Given an already-open file descriptor, read the file and return a
85 /// \param IsVolatileSize Set to true to indicate that the file size may be
86 /// changing, e.g. when libclang tries to parse while the user is
87 /// editing/updating the file.
88 static ErrorOr<std::unique_ptr<MemoryBuffer>>
89 getOpenFile(int FD, const Twine &Filename, uint64_t FileSize,
90 bool RequiresNullTerminator = true, bool IsVolatileSize = false);
92 /// Open the specified memory range as a MemoryBuffer. Note that InputData
93 /// must be null terminated if RequiresNullTerminator is true.
94 static std::unique_ptr<MemoryBuffer>
95 getMemBuffer(StringRef InputData, StringRef BufferName = "",
96 bool RequiresNullTerminator = true);
98 static std::unique_ptr<MemoryBuffer>
99 getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
101 /// Open the specified memory range as a MemoryBuffer, copying the contents
102 /// and taking ownership of it. InputData does not have to be null terminated.
103 static std::unique_ptr<MemoryBuffer>
104 getMemBufferCopy(StringRef InputData, const Twine &BufferName = "");
106 /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
107 /// that the caller need not initialize the memory allocated by this method.
108 /// The memory is owned by the MemoryBuffer object.
109 static std::unique_ptr<MemoryBuffer>
110 getNewMemBuffer(size_t Size, StringRef BufferName = "");
112 /// Allocate a new MemoryBuffer of the specified size that is not initialized.
113 /// Note that the caller should initialize the memory allocated by this
114 /// method. The memory is owned by the MemoryBuffer object.
115 static std::unique_ptr<MemoryBuffer>
116 getNewUninitMemBuffer(size_t Size, const Twine &BufferName = "");
118 /// Read all of stdin into a file buffer, and return it.
119 static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
121 /// Open the specified file as a MemoryBuffer, or open stdin if the Filename
123 static ErrorOr<std::unique_ptr<MemoryBuffer>>
124 getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1,
125 bool RequiresNullTerminator = true);
127 /// Map a subrange of the specified file as a MemoryBuffer.
128 static ErrorOr<std::unique_ptr<MemoryBuffer>>
129 getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset);
131 //===--------------------------------------------------------------------===//
132 // Provided for performance analysis.
133 //===--------------------------------------------------------------------===//
135 /// The kind of memory backing used to support the MemoryBuffer.
141 /// Return information on the memory mechanism used to support the
143 virtual BufferKind getBufferKind() const = 0;
145 MemoryBufferRef getMemBufferRef() const;
148 class MemoryBufferRef {
150 StringRef Identifier;
154 MemoryBufferRef(MemoryBuffer& Buffer)
155 : Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {}
156 MemoryBufferRef(StringRef Buffer, StringRef Identifier)
157 : Buffer(Buffer), Identifier(Identifier) {}
159 StringRef getBuffer() const { return Buffer; }
161 StringRef getBufferIdentifier() const { return Identifier; }
163 const char *getBufferStart() const { return Buffer.begin(); }
164 const char *getBufferEnd() const { return Buffer.end(); }
165 size_t getBufferSize() const { return Buffer.size(); }
168 // Create wrappers for C Binding types (see CBindingWrapping.h).
169 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
171 } // end namespace llvm