1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a family of utility functions which are useful for doing
11 // various things with files.
13 //===----------------------------------------------------------------------===//
15 #include "Support/FileUtilities.h"
16 #include "Config/unistd.h"
17 #include "Config/sys/stat.h"
18 #include "Config/sys/types.h"
23 /// CheckMagic - Returns true IFF the file named FN begins with Magic. FN must
24 /// name a readable file.
26 bool CheckMagic (const std::string &FN, const std::string &Magic) {
27 char buf[1 + Magic.size ()];
28 std::ifstream f (FN.c_str ());
29 f.read (buf, Magic.size ());
30 buf[Magic.size ()] = '\0';
34 /// IsArchive - Returns true IFF the file named FN appears to be a "ar" library
35 /// archive. The file named FN must exist.
37 bool IsArchive(const std::string &FN) {
38 // Inspect the beginning of the file to see if it contains the "ar"
39 // library archive format magic string.
40 return CheckMagic (FN, "!<arch>\012");
43 /// IsBytecode - Returns true IFF the file named FN appears to be an LLVM
44 /// bytecode file. The file named FN must exist.
46 bool IsBytecode(const std::string &FN) {
47 // Inspect the beginning of the file to see if it contains the LLVM
48 // bytecode format magic string.
49 return CheckMagic (FN, "llvm");
52 /// FileOpenable - Returns true IFF Filename names an existing regular
53 /// file which we can successfully open.
55 bool FileOpenable (const std::string &Filename) {
57 if (stat (Filename.c_str (), &s) == -1)
58 return false; // Cannot stat file
59 if (!S_ISREG (s.st_mode))
60 return false; // File is not a regular file
61 std::ifstream FileStream (Filename.c_str ());
63 return false; // File is not openable
67 /// DiffFiles - Compare the two files specified, returning true if they are
68 /// different or if there is a file error. If you specify a string to fill in
69 /// for the error option, it will set the string to an error message if an error
70 /// occurs, allowing the caller to distinguish between a failed diff and a file
73 bool DiffFiles(const std::string &FileA, const std::string &FileB,
75 std::ifstream FileAStream(FileA.c_str());
77 if (Error) *Error = "Couldn't open file '" + FileA + "'";
81 std::ifstream FileBStream(FileB.c_str());
83 if (Error) *Error = "Couldn't open file '" + FileB + "'";
87 // Compare the two files...
90 C1 = FileAStream.get();
91 C2 = FileBStream.get();
92 if (C1 != C2) return true;
99 /// MoveFileOverIfUpdated - If the file specified by New is different than Old,
100 /// or if Old does not exist, move the New file over the Old file. Otherwise,
101 /// remove the New file.
103 void MoveFileOverIfUpdated(const std::string &New, const std::string &Old) {
104 if (DiffFiles(New, Old)) {
105 if (std::rename(New.c_str(), Old.c_str()))
106 std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
108 std::remove(New.c_str());
112 /// removeFile - Delete the specified file
114 void removeFile(const std::string &Filename) {
115 std::remove(Filename.c_str());
118 /// getUniqueFilename - Return a filename with the specified prefix. If the
119 /// file does not exist yet, return it, otherwise add a suffix to make it
122 std::string getUniqueFilename(const std::string &FilenameBase) {
123 if (!std::ifstream(FilenameBase.c_str()))
124 return FilenameBase; // Couldn't open the file? Use it!
126 // Create a pattern for mkstemp...
127 char *FNBuffer = new char[FilenameBase.size()+8];
128 strcpy(FNBuffer, FilenameBase.c_str());
129 strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
131 // Agree on a temporary file name to use....
133 if ((TempFD = mkstemp(FNBuffer)) == -1) {
134 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
139 // We don't need to hold the temp file descriptor... we will trust that no one
140 // will overwrite/delete the file while we are working on it...
142 std::string Result(FNBuffer);
147 static bool AddPermissionsBits (const std::string &Filename, mode_t bits) {
148 // Get the umask value from the operating system. We want to use it
149 // when changing the file's permissions. Since calling umask() sets
150 // the umask and returns its old value, we must call it a second
151 // time to reset it to the user's preference.
152 mode_t mask = umask (0777); // The arg. to umask is arbitrary...
155 // Get the file's current mode.
157 if ((stat (Filename.c_str(), &st)) == -1)
160 // Change the file to have whichever permissions bits from 'bits'
161 // that the umask would not disable.
162 if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
168 /// MakeFileExecutable - Make the file named Filename executable by
169 /// setting whichever execute permissions bits the process's current
170 /// umask would allow. Filename must name an existing file or
171 /// directory. Returns true on success, false on error.
173 bool MakeFileExecutable (const std::string &Filename) {
174 return AddPermissionsBits (Filename, 0111);
177 /// MakeFileReadable - Make the file named Filename readable by
178 /// setting whichever read permissions bits the process's current
179 /// umask would allow. Filename must name an existing file or
180 /// directory. Returns true on success, false on error.
182 bool MakeFileReadable (const std::string &Filename) {
183 return AddPermissionsBits (Filename, 0444);