1 //===- SlowOperationInformer.h - Keep the user informed ---------*- C++ -*-===//
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 defines a simple object which can be used to let the user know what
11 // is going on when a slow operation is happening,l and gives them the ability
12 // to cancel it. Potentially slow operations can stack allocate one of these
13 // objects, and periodically call the "progress" method to update the progress
14 // bar. If the operation takes more than 3 seconds to complete, the progress
15 // bar is automatically shown and updated every second. As such, the slow
16 // operation should not print stuff to the screen, and should not be confused if
17 // an extra line appears on the screen (ie, the cursor should be at the start of
20 // If the user presses CTRL-C during the operation, the next invocation of the
21 // progress method with throw an std::string object indicating that the
22 // operation was cancelled. As such, client code must be exception safe around
23 // the progress method.
25 // Because SlowOperationInformers fiddle around with signals, they cannot be
26 // nested. The SIGINT signal handler is restored after the
27 // SlowOperationInformer is destroyed, but the SIGALRM handlers is set back to
30 //===----------------------------------------------------------------------===//
32 #ifndef SUPPORT_SLOW_OPERATION_INFORMER_H
33 #define SUPPORT_SLOW_OPERATION_INFORMER_H
38 class SlowOperationInformer {
39 std::string OperationName;
40 unsigned LastPrintAmount;
42 SlowOperationInformer(const SlowOperationInformer&); // DO NOT IMPLEMENT
43 void operator=(const SlowOperationInformer&); // DO NOT IMPLEMENT
45 SlowOperationInformer(const std::string &Name);
46 ~SlowOperationInformer();
48 /// progress - Clients should periodically call this method when they are in
49 /// an exception-safe state. The Amount variable should indicate how far
50 /// along the operation is, given in 1/10ths of a percent (in other words,
51 /// Amount should range from 0 to 1000).
52 void progress(unsigned Amount);
54 } // end namespace llvm
56 #endif /* SLOW_OPERATION_INFORMER_H */