New class, useful for command-line interactive programs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10662 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 94 insertions, 0 deletions

diff --git a/lib/Support/SlowOperationInformer.cpp b/lib/Support/SlowOperationInformer.cpp
new file mode 100644
index 0000000000..40759f6d48
--- /dev/null
+++ b/lib/Support/SlowOperationInformer.cpp
@@ -0,0 +1,94 @@
+//===-- SlowOperationInformer.cpp - Keep the user informed ----------------===//
+// 
+//                     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 implements the SlowOperationInformer class for the LLVM debugger.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Support/SlowOperationInformer.h"
+#include "Config/config.h"     // Get the signal handler return type
+#include <iostream>
+#include <sstream>
+#include <signal.h>
+#include <unistd.h>
+using namespace llvm;
+
+/// OperationCancelled - This flag is set by the SIGINT signal handler if the
+/// user presses CTRL-C.
+static volatile bool OperationCancelled;
+
+/// ShouldShowStatus - This flag gets set if the operation takes a long time.
+///
+static volatile bool ShouldShowStatus;
+
+/// NestedSOI - Sanity check.  SlowOperationInformers cannot be nested or run in
+/// parallel.  This ensures that they never do.
+static bool NestedSOI = false;
+
+static RETSIGTYPE SigIntHandler(int Sig) {
+  OperationCancelled = true;
+  signal(SIGINT, SigIntHandler);
+}
+
+static RETSIGTYPE SigAlarmHandler(int Sig) {
+  ShouldShowStatus = true;
+}
+
+static sighandler_t OldSigIntHandler;
+
+
+SlowOperationInformer::SlowOperationInformer(const std::string &Name)
+  : OperationName(Name), LastPrintAmount(0) {
+  assert(!NestedSOI && "SlowerOperationInformer objects cannot be nested!");
+  NestedSOI = true;
+
+  OperationCancelled = 0;
+  ShouldShowStatus = 0;
+
+  signal(SIGALRM, SigAlarmHandler);
+  OldSigIntHandler = signal(SIGINT, SigIntHandler);
+  alarm(1);
+}
+
+SlowOperationInformer::~SlowOperationInformer() {
+  NestedSOI = false;
+  if (LastPrintAmount)
+    std::cout << "\n";
+
+  alarm(0);
+  signal(SIGALRM, SIG_DFL);
+  signal(SIGINT, OldSigIntHandler);
+}
+
+/// progress - Clients should periodically call this method when they are in
+/// an exception-safe state.  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).
+void SlowOperationInformer::progress(unsigned Amount) {
+  if (OperationCancelled) {
+    std::cout << "\n";
+    LastPrintAmount = 0;
+    throw "While " + OperationName + ", operation cancelled.";
+  }
+
+  // If we haven't spent enough time in this operation to warrant displaying the
+  // progress bar, don't do so yet.
+  if (!ShouldShowStatus)
+    return;
+
+  // Delete whatever we printed last time.
+  std::string ToPrint = std::string(LastPrintAmount, '\b');
+
+  std::ostringstream OS;
+  OS << "Progress " << OperationName << ": " << Amount/10 << "." << Amount % 10
+     << "%";
+
+  LastPrintAmount = OS.str().size();
+  std::cout << ToPrint+OS.str() << std::flush;
+}