From 390337f6753a42e858bddfeb8d1511303c8fa9d7 Mon Sep 17 00:00:00 2001
From: Anton Makeev <Anton.Makeev@jetbrains.com>
Date: Wed, 25 May 2011 14:05:57 +0200
Subject: [PATCH] AppCode: caching files, libraries, and frameworks in
 XcodeMetaData + XcodeProjectModificationTracker + central events about
 various project modifications

---
 .../util/DefaultModificationTracker.java       | 16 ++++++++++++++++
 .../openapi/util/ModificationTracker.java      |  1 +
 .../src/com/intellij/util/CachedValueBase.java | 18 ++++++++++++++++--
 3 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 platform/platform-api/src/com/intellij/openapi/util/DefaultModificationTracker.java

diff --git a/platform/platform-api/src/com/intellij/openapi/util/DefaultModificationTracker.java b/platform/platform-api/src/com/intellij/openapi/util/DefaultModificationTracker.java
new file mode 100644
index 000000000000..05f8417e1780
--- /dev/null
+++ b/platform/platform-api/src/com/intellij/openapi/util/DefaultModificationTracker.java
@@ -0,0 +1,16 @@
+package com.intellij.openapi.util;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+public class DefaultModificationTracker implements ModificationTracker {
+  private volatile AtomicLong myCount = new AtomicLong();
+
+  @Override
+  public long getModificationCount() {
+    return myCount.get();
+  }
+
+  public void incModificationCount() {
+    myCount.incrementAndGet();
+  }
+}
diff --git a/platform/platform-api/src/com/intellij/openapi/util/ModificationTracker.java b/platform/platform-api/src/com/intellij/openapi/util/ModificationTracker.java
index 5fc9b009184b..bcac21adbf86 100644
--- a/platform/platform-api/src/com/intellij/openapi/util/ModificationTracker.java
+++ b/platform/platform-api/src/com/intellij/openapi/util/ModificationTracker.java
@@ -23,6 +23,7 @@ public interface ModificationTracker {
 
   ModificationTracker EVER_CHANGED = new ModificationTracker() {
     private long myCounter = 0;
+
     public long getModificationCount() {
       return myCounter++;
     }
diff --git a/platform/platform-impl/src/com/intellij/util/CachedValueBase.java b/platform/platform-impl/src/com/intellij/util/CachedValueBase.java
index d8d71dbbef68..c333c2fc9ea5 100644
--- a/platform/platform-impl/src/com/intellij/util/CachedValueBase.java
+++ b/platform/platform-impl/src/com/intellij/util/CachedValueBase.java
@@ -29,6 +29,7 @@ import org.jetbrains.annotations.Nullable;
 import java.lang.ref.Reference;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicLong;
 
 /**
  * @author Dmitry Avdeev
@@ -80,8 +81,7 @@ public abstract class CachedValueBase<T> {
 
   @Nullable
   private T getUpToDateOrNull(boolean dispose) {
-    final SoftReference<Data<T>> ref = myData;
-    final Data<T> data = ref == null ? null : ref.get();
+    final Data<T> data = getData();
 
     if (data != null) {
       T value = data.myValue;
@@ -95,6 +95,12 @@ public abstract class CachedValueBase<T> {
     return null;
   }
 
+  @Nullable
+  private Data<T> getData() {
+    final SoftReference<Data<T>> ref = myData;
+    return ref == null ? null : ref.get();
+  }
+
   protected boolean isUpToDate(@NotNull Data data) {
     if (data.myTimeStamps == null) return true;
 
@@ -129,6 +135,10 @@ public abstract class CachedValueBase<T> {
     if (dependency instanceof ModificationTracker) {
       return ((ModificationTracker)dependency).getModificationCount();
     }
+    else if (dependency instanceof CachedValueBase) {
+      Data data = ((CachedValueBase)dependency).getData();
+      return data == null || !isUpToDate(data) ? -1 : data.myTimestamp;
+    }
     else if (dependency instanceof Reference){
       final Object original = ((Reference)dependency).get();
       if(original == null) return -1;
@@ -157,11 +167,15 @@ public abstract class CachedValueBase<T> {
   public abstract boolean isFromMyProject(Project project);
 
   protected static class Data<T> implements Disposable {
+    private static final AtomicLong ourCounter = new AtomicLong();
+
+    private final long myTimestamp;
     private final T myValue;
     private final Object[] myDependencies;
     private final long[] myTimeStamps;
 
     public Data(final T value, final Object[] dependencies, final long[] timeStamps) {
+      myTimestamp = ourCounter.incrementAndGet();
       myValue = value;
       myDependencies = dependencies;
       myTimeStamps = timeStamps;