1 //===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the MemoryBuffer interface. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_SUPPORT_MEMORYBUFFER_H 15 #define LLVM_SUPPORT_MEMORYBUFFER_H 16 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" 23 #include <memory> 24 #include <system_error> 25 26 namespace llvm { 27 class MemoryBufferRef; 28 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'. 34 /// 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. 39 class MemoryBuffer { 40 const char *BufferStart; // Start of the buffer. 41 const char *BufferEnd; // End of the buffer. 42 43 MemoryBuffer(const MemoryBuffer &) LLVM_DELETED_FUNCTION; 44 MemoryBuffer &operator=(const MemoryBuffer &) LLVM_DELETED_FUNCTION; 45 protected: MemoryBuffer()46 MemoryBuffer() {} 47 void init(const char *BufStart, const char *BufEnd, 48 bool RequiresNullTerminator); 49 public: 50 virtual ~MemoryBuffer(); 51 getBufferStart()52 const char *getBufferStart() const { return BufferStart; } getBufferEnd()53 const char *getBufferEnd() const { return BufferEnd; } getBufferSize()54 size_t getBufferSize() const { return BufferEnd-BufferStart; } 55 getBuffer()56 StringRef getBuffer() const { 57 return StringRef(BufferStart, getBufferSize()); 58 } 59 60 /// Return an identifier for this buffer, typically the filename it was read 61 /// from. getBufferIdentifier()62 virtual const char *getBufferIdentifier() const { 63 return "Unknown buffer"; 64 } 65 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 69 /// specified size. 70 /// 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(const Twine &Filename, int64_t FileSize = -1, 76 bool RequiresNullTerminator = true, bool IsVolatileSize = false); 77 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. 81 static ErrorOr<std::unique_ptr<MemoryBuffer>> 82 getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize, 83 int64_t Offset); 84 85 /// Given an already-open file descriptor, read the file and return a 86 /// MemoryBuffer. 87 /// 88 /// \param IsVolatileSize Set to true to indicate that the file size may be 89 /// changing, e.g. when libclang tries to parse while the user is 90 /// editing/updating the file. 91 static ErrorOr<std::unique_ptr<MemoryBuffer>> 92 getOpenFile(int FD, const Twine &Filename, uint64_t FileSize, 93 bool RequiresNullTerminator = true, bool IsVolatileSize = false); 94 95 /// Open the specified memory range as a MemoryBuffer. Note that InputData 96 /// must be null terminated if RequiresNullTerminator is true. 97 static std::unique_ptr<MemoryBuffer> 98 getMemBuffer(StringRef InputData, StringRef BufferName = "", 99 bool RequiresNullTerminator = true); 100 101 static std::unique_ptr<MemoryBuffer> 102 getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true); 103 104 /// Open the specified memory range as a MemoryBuffer, copying the contents 105 /// and taking ownership of it. InputData does not have to be null terminated. 106 static std::unique_ptr<MemoryBuffer> 107 getMemBufferCopy(StringRef InputData, const Twine &BufferName = ""); 108 109 /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note 110 /// that the caller need not initialize the memory allocated by this method. 111 /// The memory is owned by the MemoryBuffer object. 112 static std::unique_ptr<MemoryBuffer> 113 getNewMemBuffer(size_t Size, StringRef BufferName = ""); 114 115 /// Allocate a new MemoryBuffer of the specified size that is not initialized. 116 /// Note that the caller should initialize the memory allocated by this 117 /// method. The memory is owned by the MemoryBuffer object. 118 static std::unique_ptr<MemoryBuffer> 119 getNewUninitMemBuffer(size_t Size, const Twine &BufferName = ""); 120 121 /// Read all of stdin into a file buffer, and return it. 122 static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN(); 123 124 /// Open the specified file as a MemoryBuffer, or open stdin if the Filename 125 /// is "-". 126 static ErrorOr<std::unique_ptr<MemoryBuffer>> 127 getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1); 128 129 /// Map a subrange of the the specified file as a MemoryBuffer. 130 static ErrorOr<std::unique_ptr<MemoryBuffer>> 131 getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset); 132 133 //===--------------------------------------------------------------------===// 134 // Provided for performance analysis. 135 //===--------------------------------------------------------------------===// 136 137 /// The kind of memory backing used to support the MemoryBuffer. 138 enum BufferKind { 139 MemoryBuffer_Malloc, 140 MemoryBuffer_MMap 141 }; 142 143 /// Return information on the memory mechanism used to support the 144 /// MemoryBuffer. 145 virtual BufferKind getBufferKind() const = 0; 146 147 MemoryBufferRef getMemBufferRef() const; 148 }; 149 150 class MemoryBufferRef { 151 StringRef Buffer; 152 StringRef Identifier; 153 154 public: MemoryBufferRef()155 MemoryBufferRef() {} MemoryBufferRef(StringRef Buffer,StringRef Identifier)156 MemoryBufferRef(StringRef Buffer, StringRef Identifier) 157 : Buffer(Buffer), Identifier(Identifier) {} 158 getBuffer()159 StringRef getBuffer() const { return Buffer; } 160 getBufferIdentifier()161 StringRef getBufferIdentifier() const { return Identifier; } 162 getBufferStart()163 const char *getBufferStart() const { return Buffer.begin(); } getBufferEnd()164 const char *getBufferEnd() const { return Buffer.end(); } getBufferSize()165 size_t getBufferSize() const { return Buffer.size(); } 166 }; 167 168 // Create wrappers for C Binding types (see CBindingWrapping.h). 169 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef) 170 171 } // end namespace llvm 172 173 #endif 174