Lazily create the CommandRunner in Builder::Build

This allows the user to interrupt the build (i.e. using Ctrl-C)
while the build plan is being computed.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/build.cc b/src/build.cc
index d3e88ee..2b9c657 100644
--- a/src/build.cc
+++ b/src/build.cc
@@ -479,10 +479,6 @@ struct DryRunCommandRunner : public CommandRunner {
 Builder::Builder(State* state, const BuildConfig& config)
     : state_(state), config_(config) {
   disk_interface_ = new RealDiskInterface;
-  if (config.dry_run)
-    command_runner_.reset(new DryRunCommandRunner);
-  else
-    command_runner_.reset(new RealCommandRunner(config));
   status_ = new BuildStatus(config);
   log_ = state->build_log_;
 }
@@ -540,6 +536,14 @@ bool Builder::Build(string* err) {
   int pending_commands = 0;
   int failures_allowed = config_.failures_allowed;
 
+  // Set up the command runner if we haven't done so already.
+  if (!command_runner_.get()) {
+    if (config_.dry_run)
+      command_runner_.reset(new DryRunCommandRunner);
+    else
+      command_runner_.reset(new RealCommandRunner(config_));
+  }
+
   // This main loop runs the entire build process.
   // It is structured like this:
   // First, we attempt to start as many commands as allowed by the