From 931aac42522c7e4a340cc77bb115ba89d808c7a5 Mon Sep 17 00:00:00 2001
From: Petr Wolf <petr.wolf@gmail.com>
Date: Thu, 4 Oct 2012 15:42:15 -0400
Subject: Improve the efficiency of -t clean

Prevent each node from being examined for cleaning multiple times, if it
is used in several other nodes
---
 src/clean.cc | 12 +++++++++++-
 src/clean.h  |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/clean.cc b/src/clean.cc
index 3fe23ec..c9d4cbd 100644
--- a/src/clean.cc
+++ b/src/clean.cc
@@ -29,6 +29,7 @@ Cleaner::Cleaner(State* state, const BuildConfig& config)
   : state_(state),
     config_(config),
     removed_(),
+    cleaned_(),
     cleaned_files_count_(0),
     disk_interface_(new RealDiskInterface),
     status_(0) {
@@ -40,6 +41,7 @@ Cleaner::Cleaner(State* state,
   : state_(state),
     config_(config),
     removed_(),
+    cleaned_(),
     cleaned_files_count_(0),
     disk_interface_(disk_interface),
     status_(0) {
@@ -134,9 +136,16 @@ void Cleaner::DoCleanTarget(Node* target) {
     }
     for (vector<Node*>::iterator n = e->inputs_.begin(); n != e->inputs_.end();
          ++n) {
-      DoCleanTarget(*n);
+      Node* next = *n;
+      // call DoCleanTarget recursively if this node has not been visited
+      if (cleaned_.count(next) == 0) {
+        DoCleanTarget(next);
+      }
     }
   }
+
+  // mark this target to be cleaned already
+  cleaned_.insert(target);
 }
 
 int Cleaner::CleanTarget(Node* target) {
@@ -249,4 +258,5 @@ void Cleaner::Reset() {
   status_ = 0;
   cleaned_files_count_ = 0;
   removed_.clear();
+  cleaned_.clear();
 }
diff --git a/src/clean.h b/src/clean.h
index 5938dff..8359901 100644
--- a/src/clean.h
+++ b/src/clean.h
@@ -95,6 +95,7 @@ class Cleaner {
   State* state_;
   const BuildConfig& config_;
   set<string> removed_;
+  set<Node*> cleaned_;
   int cleaned_files_count_;
   DiskInterface* disk_interface_;
   int status_;
-- 
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