lib/Support/SlowOperationInformer.cpp

   1 //===-- SlowOperationInformer.cpp - Keep the user informed ----------------===//
   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 implements the SlowOperationInformer class for the LLVM debugger.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Support/SlowOperationInformer.h"
  15 #include "llvm/Support/raw_ostream.h"
  16 #include "llvm/System/Alarm.h"
  17 #include <sstream>
  18 #include <cassert>
  19 using namespace llvm;
  20
  21 SlowOperationInformer::SlowOperationInformer(const std::string &Name)
  22   : OperationName(Name), LastPrintAmount(0) {
  23   sys::SetupAlarm(1);
  24 }
  25
  26 SlowOperationInformer::~SlowOperationInformer() {
  27   sys::TerminateAlarm();
  28   if (LastPrintAmount) {
  29     // If we have printed something, make _sure_ we print the 100% amount, and
  30     // also print a newline.
  31     outs() << std::string(LastPrintAmount, '\b') << "Progress "
  32            << OperationName << ": 100%  \n";
  33   }
  34 }
  35
  36 /// progress - Clients should periodically call this method when they are in
  37 /// an exception-safe state.  The Amount variable should indicate how far
  38 /// along the operation is, given in 1/10ths of a percent (in other words,
  39 /// Amount should range from 0 to 1000).
  40 bool SlowOperationInformer::progress(unsigned Amount) {
  41   int status = sys::AlarmStatus();
  42   if (status == -1) {
  43     outs() << "\n";
  44     LastPrintAmount = 0;
  45     return true;
  46   }
  47
  48   // If we haven't spent enough time in this operation to warrant displaying the
  49   // progress bar, don't do so yet.
  50   if (status == 0)
  51     return false;
  52
  53   // Delete whatever we printed last time.
  54   std::string ToPrint = std::string(LastPrintAmount, '\b');
  55
  56   std::ostringstream OS;
  57   OS << "Progress " << OperationName << ": " << Amount/10;
  58   if (unsigned Rem = Amount % 10)
  59     OS << "." << Rem << "%";
  60   else
  61     OS << "%  ";
  62
  63   LastPrintAmount = OS.str().size();
  64   outs() << ToPrint+OS.str();
  65   outs().flush();
  66   return false;
  67 }