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"
22 #include "llvm/Support/ErrorOr.h"
24 #include <system_error>
27 class MemoryBufferRef;
29 /// This interface provides simple read-only access to a block of memory, and
30 /// provides simple methods for reading files and standard input into a memory
31 /// buffer. In addition to basic access to the characters in the file, this
32 /// interface guarantees you can read one character past the end of the file,
33 /// and that this character will read as '\0'.
35 /// The '\0' guarantee is needed to support an optimization -- it's intended to
36 /// be more efficient for clients which are reading all the data to stop
37 /// reading when they encounter a '\0' than to continually check the file
38 /// position to see if it has reached the end of the file.
40 const char *BufferStart; // Start of the buffer.
41 const char *BufferEnd; // End of the buffer.
43 MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
44 MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION;
47 void init(const char *BufStart, const char *BufEnd,
48 bool RequiresNullTerminator);
50 virtual ~MemoryBuffer();
52 const char *getBufferStart() const { return BufferStart; }
53 const char *getBufferEnd() const { return BufferEnd; }
54 size_t getBufferSize() const { return BufferEnd-BufferStart; }
56 StringRef getBuffer() const {
57 return StringRef(BufferStart, getBufferSize());
60 /// Return an identifier for this buffer, typically the filename it was read
62 virtual const char *getBufferIdentifier() const {
63 return "Unknown buffer";
66 /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
67 /// if successful, otherwise returning null. If FileSize is specified, this
68 /// means that the client knows that the file exists and that it has the
71 /// \param IsVolatileSize Set to true to indicate that the file size may be
72 /// changing, e.g. when libclang tries to parse while the user is
73 /// editing/updating the file.
74 static ErrorOr<std::unique_ptr<MemoryBuffer>>
75 getFile(Twine Filename, int64_t FileSize = -1,
76 bool RequiresNullTerminator = true, 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 ErrorOr<std::unique_ptr<MemoryBuffer>>
86 getOpenFileSlice(int FD, const char *Filename, uint64_t MapSize,
87 int64_t Offset, 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 ErrorOr<std::unique_ptr<MemoryBuffer>>
96 getOpenFile(int FD, const char *Filename, uint64_t FileSize,
97 bool RequiresNullTerminator = true, bool IsVolatileSize = false);
99 /// Open the specified memory range as a MemoryBuffer. Note that InputData
100 /// must be null terminated if RequiresNullTerminator is true.
101 static std::unique_ptr<MemoryBuffer>
102 getMemBuffer(StringRef InputData, StringRef BufferName = "",
103 bool RequiresNullTerminator = true);
105 static std::unique_ptr<MemoryBuffer>
106 getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
108 /// Open the specified memory range as a MemoryBuffer, copying the contents
109 /// and taking ownership of it. InputData does not have to be null terminated.
110 static std::unique_ptr<MemoryBuffer>
111 getMemBufferCopy(StringRef InputData, StringRef BufferName = "");
113 /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
114 /// that the caller need not initialize the memory allocated by this method.
115 /// The memory is owned by the MemoryBuffer object.
116 static std::unique_ptr<MemoryBuffer>
117 getNewMemBuffer(size_t Size, StringRef BufferName = "");
119 /// Allocate a new MemoryBuffer of the specified size that is not initialized.
120 /// Note that the caller should initialize the memory allocated by this
121 /// method. The memory is owned by the MemoryBuffer object.
122 static std::unique_ptr<MemoryBuffer>
123 getNewUninitMemBuffer(size_t Size, StringRef BufferName = "");
125 /// Read all of stdin into a file buffer, and return it.
126 static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
128 /// Open the specified file as a MemoryBuffer, or open stdin if the Filename
130 static ErrorOr<std::unique_ptr<MemoryBuffer>>
131 getFileOrSTDIN(StringRef Filename, int64_t FileSize = -1);
133 //===--------------------------------------------------------------------===//
134 // Provided for performance analysis.
135 //===--------------------------------------------------------------------===//
137 /// The kind of memory backing used to support the MemoryBuffer.
143 /// Return information on the memory mechanism used to support the
145 virtual BufferKind getBufferKind() const = 0;
147 MemoryBufferRef getMemBufferRef() const;
150 class MemoryBufferRef {
152 StringRef Identifier;
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