FileUpdate.cpp revision 3ff9563c3e391954b2e224afcf8b2b0fcc3888aa
105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar//===- FileUpdate.cpp - Conditionally update a file -----------------------===// 205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// 305084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// The LLVM Compiler Infrastructure 405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// 505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// This file is distributed under the University of Illinois Open Source 605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// License. See LICENSE.TXT for details. 705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// 805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar//===----------------------------------------------------------------------===// 905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// 1005084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// FileUpdate is a utility for conditionally updating a file from its input 1105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// based on whether the input differs from the output. It is used to avoid 1205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// unnecessary modifications in a build system. 1305084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar// 1405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar//===----------------------------------------------------------------------===// 1505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 1605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar#include "llvm/Support/CommandLine.h" 1705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar#include "llvm/Support/MemoryBuffer.h" 183ff9563c3e391954b2e224afcf8b2b0fcc3888aaMichael J. Spencer#include "llvm/ADT/OwningPtr.h" 1905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar#include "llvm/Support/PrettyStackTrace.h" 20e4f1a9b8a272ff7452759019ee7774e9dbdf1568Dan Gohman#include "llvm/Support/ToolOutputFile.h" 215fae2f1dbb8345e6fc3232f4732acaf9b64edd90Michael J. Spencer#include "llvm/Support/Signals.h" 227a8aab3997e48aabe819de43b369d441ec4f533aMichael J. Spencer#include "llvm/Support/system_error.h" 2305084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbarusing namespace llvm; 2405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 2505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbarstatic cl::opt<bool> 2605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel DunbarQuiet("quiet", cl::desc("Don't print unnecessary status information"), 2705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar cl::init(false)); 2805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 2905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbarstatic cl::opt<std::string> 3005084716c13b4ea79ea29528dcb3c3f8a5271638Daniel DunbarInputFilename("input-file", cl::desc("Input file (defaults to stdin)"), 3105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar cl::init("-"), cl::value_desc("filename")); 3205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 3305084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbarstatic cl::opt<std::string> 3405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel DunbarOutputFilename(cl::Positional, cl::desc("<output-file>"), cl::Required); 3505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 3605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbarint main(int argc, char **argv) { 3705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar sys::PrintStackTraceOnErrorSignal(); 3805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar PrettyStackTraceProgram X(argc, argv); 3905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar cl::ParseCommandLineOptions(argc, argv); 4005084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 41e7b67d0e94df497791207618194e1db545ac3721Dan Gohman if (OutputFilename == "-") { 42e7b67d0e94df497791207618194e1db545ac3721Dan Gohman errs() << argv[0] << ": error: Can't update standard output\n"; 43e7b67d0e94df497791207618194e1db545ac3721Dan Gohman return 1; 44e7b67d0e94df497791207618194e1db545ac3721Dan Gohman } 45e7b67d0e94df497791207618194e1db545ac3721Dan Gohman 4605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar // Get the input data. 473ff9563c3e391954b2e224afcf8b2b0fcc3888aaMichael J. Spencer OwningPtr<MemoryBuffer> In; 483ff9563c3e391954b2e224afcf8b2b0fcc3888aaMichael J. Spencer if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename.c_str(), In)) { 4905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar errs() << argv[0] << ": error: Unable to get input '" 507a8aab3997e48aabe819de43b369d441ec4f533aMichael J. Spencer << InputFilename << "': " << ec.message() << '\n'; 5105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar return 1; 5205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar } 5305084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 5405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar // Get the output data. 553ff9563c3e391954b2e224afcf8b2b0fcc3888aaMichael J. Spencer OwningPtr<MemoryBuffer> Out; 563ff9563c3e391954b2e224afcf8b2b0fcc3888aaMichael J. Spencer MemoryBuffer::getFile(OutputFilename.c_str(), Out); 5705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 5805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar // If the output exists and the contents match, we are done. 5905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar if (Out && In->getBufferSize() == Out->getBufferSize() && 6005084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar memcmp(In->getBufferStart(), Out->getBufferStart(), 6105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar Out->getBufferSize()) == 0) { 6205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar if (!Quiet) 637a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman errs() << argv[0] << ": Not updating '" << OutputFilename 6405084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar << "', contents match input.\n"; 6505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar return 0; 6605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar } 6705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 6805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar // Otherwise, overwrite the output. 6905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar if (!Quiet) 707a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman errs() << argv[0] << ": Updating '" << OutputFilename 7105084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar << "', contents changed.\n"; 727a8aab3997e48aabe819de43b369d441ec4f533aMichael J. Spencer std::string ErrorStr; 737a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman tool_output_file OutStream(OutputFilename.c_str(), ErrorStr, 747a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman raw_fd_ostream::F_Binary); 7505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar if (!ErrorStr.empty()) { 7605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar errs() << argv[0] << ": Unable to write output '" 7705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar << OutputFilename << "': " << ErrorStr << '\n'; 7805084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar return 1; 7905084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar } 8005084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 81d4c454317a38d65957edebe62bfc69fc8d9885e8Dan Gohman OutStream.os().write(In->getBufferStart(), In->getBufferSize()); 8205084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 837a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman // Declare success. 847a4575e26e58da743cf6c921aadd0d5499717a68Dan Gohman OutStream.keep(); 8505084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar 8605084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar return 0; 8705084716c13b4ea79ea29528dcb3c3f8a5271638Daniel Dunbar} 88