Files.app: Let DirectoryContents controls metadata cache size by relative value

Previously, DirectoryContents controlled the size of metadata cache by absolute value. But multiple of instances of DirectoryContents might be created at same time and it might set wrong cache size. 

This patch lets DirectoryContents controls metadata cache size by relative value, instead of absolute value, and solves that problem.

BUG=373629
TEST=manually

Review URL: https://codereview.chromium.org/310633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275771 0039d316-1c4b-4281-b951-d872f2087c98

ui/file_manager/file_manager/foreground/js/directory_contents.js

@@ -455,6 +455,8 @@ function DirectoryContents(context,
   this.scanner_ = null;
   this.processNewEntriesQueue_ = new AsyncUtil.Queue();
   this.scanCancelled_ = false;
+
+  this.lastSpaceInMetadataCache_ = 0;
 }
 
 /**
@@ -474,6 +476,24 @@ DirectoryContents.prototype.clone = function() {
       this.scannerFactory_);
 };
 
+/**
+ * Disposes the reserved metadata cache.
+ */
+DirectoryContents.prototype.dispose = function() {
+  this.context_.metadataCache.resizeBy(-this.lastSpaceInMetadataCache_);
+};
+
+/**
+ * Make a space for current directory size in the metadata cache.
+ *
+ * @param {number} size The cache size to be set.
+ * @private
+ */
+DirectoryContents.prototype.makeSpaceInMetadataCache_ = function(size) {
+  this.context_.metadataCache.resizeBy(size - this.lastSpaceInMetadataCache_);
+  this.lastSpaceInMetadataCache_ = size;
+};
+
 /**
  * Use a given fileList instead of the fileList from the context.
  * @param {Array|cr.ui.ArrayDataModel} fileList The new file list.
@@ -483,7 +503,7 @@ DirectoryContents.prototype.setFileList = function(fileList) {
     this.fileList_ = fileList;
   else
     this.fileList_ = new cr.ui.ArrayDataModel(fileList);
-  this.context_.metadataCache.setCacheSize(this.fileList_.length);
+  this.makeSpaceInMetadataCache_(this.fileList_.length);
 };
 
 /**
@@ -497,7 +517,7 @@ DirectoryContents.prototype.replaceContextFileList = function() {
     spliceArgs.unshift(0, fileList.length);
     fileList.splice.apply(fileList, spliceArgs);
     this.fileList_ = fileList;
-    this.context_.metadataCache.setCacheSize(this.fileList_.length);
+    this.makeSpaceInMetadataCache_(this.fileList_.length);
   }
 };
 
@@ -650,7 +670,7 @@ DirectoryContents.prototype.onNewEntries_ = function(entries) {
   this.fileList_.push.apply(this.fileList_, entriesFiltered);
   cr.dispatchSimpleEvent(this, 'scan-updated');
 
-  this.context_.metadataCache.setCacheSize(this.fileList_.length);
+  this.makeSpaceInMetadataCache_(this.fileList_.length);
 
   this.processNewEntriesQueue_.run(function(callbackOuter) {
     // Because the prefetchMetadata can be slow, throttling by splitting entries

ui/file_manager/file_manager/foreground/js/directory_model.js

@@ -497,6 +497,7 @@ DirectoryModel.prototype.replaceDirectoryContents_ = function(dirContents) {
     var leadIndex = this.fileListSelection_.leadIndex;
     var leadEntry = this.getLeadEntry_();
 
+    this.currentDirContents_.dispose();
     this.currentDirContents_ = dirContents;
     dirContents.replaceContextFileList();
 

ui/file_manager/file_manager/foreground/js/metadata/metadata_cache.js

@@ -163,12 +163,15 @@ MetadataCache.prototype.isInitialized = function() {
 };
 
 /**
- * Sets the size of cache. The actual cache size may be larger than the given
- * value.
- * @param {number} size The cache size to be set.
+ * Changes the size of cache by delta value. The actual cache size may be larger
+ * than the given value.
+ *
+ * @param {number} delta The delta size to be changed the cache size by.
  */
-MetadataCache.prototype.setCacheSize = function(size) {
-  this.currentCacheSize_ = size;
+MetadataCache.prototype.resizeBy = function(delta) {
+  this.currentCacheSize_ += delta;
+  if (this.currentCacheSize_ < 0)
+    this.currentCacheSize_ = 0;
 
   if (this.totalCount_ > this.currentEvictionThreshold_())
     this.evict_();