//===- llvm/Support/SlowOperationInformer.h - Keep user informed *- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file was developed by the LLVM research group and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines a simple object which can be used to let the user know what // is going on when a slow operation is happening, and gives them the ability to // cancel it. Potentially slow operations can stack allocate one of these // objects, and periodically call the "progress" method to update the progress // bar. If the operation takes more than 1 second to complete, the progress bar // is automatically shown and updated. As such, the slow operation should not // print stuff to the screen, and should not be confused if an extra line // appears on the screen (ie, the cursor should be at the start of the line). // // If the user presses CTRL-C during the operation, the next invocation of the // progress method return true indicating that the operation was cancelled. // // Because SlowOperationInformers fiddle around with signals, they cannot be // nested, and interact poorly with threads. The SIGALRM handler is set back to // SIGDFL, but the SIGINT signal handler is restored when the // SlowOperationInformer is destroyed. // //===----------------------------------------------------------------------===// #ifndef LLVM_SUPPORT_SLOW_OPERATION_INFORMER_H #define LLVM_SUPPORT_SLOW_OPERATION_INFORMER_H #include <string> #include <cassert> #include "llvm/Support/DataTypes.h" namespace llvm { class SlowOperationInformer { std::string OperationName; unsigned LastPrintAmount; SlowOperationInformer(const SlowOperationInformer&); // DO NOT IMPLEMENT void operator=(const SlowOperationInformer&); // DO NOT IMPLEMENT public: SlowOperationInformer(const std::string &Name); ~SlowOperationInformer(); /// progress - Clients should periodically call this method when they can /// handle cancellation. The Amount variable should indicate how far /// along the operation is, given in 1/10ths of a percent (in other words, /// Amount should range from 0 to 1000). If the user cancels the operation, /// this returns true, false otherwise. bool progress(unsigned Amount); /// progress - Same as the method above, but this performs the division for /// you, and helps you avoid overflow if you are dealing with largish /// numbers. bool progress(unsigned Current, unsigned Maximum) { assert(Maximum != 0 && "Shouldn't be doing work if there is nothing to do!"); return progress(Current*uint64_t(1000UL)/Maximum); } }; } // end namespace llvm #endif /* SLOW_OPERATION_INFORMER_H */