Bug 1271701 - Make about:cache channels cancelable. r=michal

netwerk/cache2/CacheStorageService.cpp

@@ -186,6 +186,7 @@ protected:
     , mSize(0)
     , mNotifyStorage(true)
     , mVisitEntries(aVisitEntries)
+    , mCancel(false)
   {
     MOZ_ASSERT(NS_IsMainThread());
   }
@@ -204,6 +205,8 @@ protected:
 
   bool mNotifyStorage : 1;
   bool mVisitEntries : 1;
+
+  Atomic<bool> mCancel;
 };
 
 // WalkMemoryCacheRunnable
@@ -274,10 +277,10 @@ private:
         mNotifyStorage = false;
 
       } else {
-        LOG(("  entry [left=%d]", mEntryArray.Length()));
+        LOG(("  entry [left=%d, canceled=%d]", mEntryArray.Length(), (bool)mCancel));
 
-        // Third, notify each entry until depleted
-        if (!mEntryArray.Length()) {
+        // Third, notify each entry until depleted or canceled
+        if (!mEntryArray.Length() || mCancel) {
           mCallback->OnCacheEntryVisitCompleted();
           return NS_OK; // done
         }
@@ -310,13 +313,20 @@ private:
                            uint32_t aLastModifiedTime, uint32_t aExpirationTime,
                            bool aPinned)
   {
-    nsCOMPtr<nsIURI> uri;
-    nsresult rv = NS_NewURI(getter_AddRefs(uri), aURISpec);
-    if (NS_FAILED(rv))
-      return;
+    nsresult rv;
 
-    mCallback->OnCacheEntryInfo(uri, aIdEnhance, aDataSize, aFetchCount,
-                                aLastModifiedTime, aExpirationTime, aPinned);
+    nsCOMPtr<nsIURI> uri;
+    rv = NS_NewURI(getter_AddRefs(uri), aURISpec);
+    if (NS_FAILED(rv)) {
+      return;
+    }
+
+    rv = mCallback->OnCacheEntryInfo(uri, aIdEnhance, aDataSize, aFetchCount,
+                                     aLastModifiedTime, aExpirationTime, aPinned);
+    if (NS_FAILED(rv)) {
+      LOG(("  callback failed, canceling the walk"));
+      mCancel = true;
+    }
   }
 
 private:
@@ -369,14 +379,21 @@ private:
     {
       MOZ_ASSERT(NS_IsMainThread());
 
-      nsCOMPtr<nsIURI> uri;
-      nsresult rv = NS_NewURI(getter_AddRefs(uri), mURISpec);
-      if (NS_FAILED(rv))
-        return NS_OK;
+      nsresult rv;
 
-      mWalker->mCallback->OnCacheEntryInfo(
+      nsCOMPtr<nsIURI> uri;
+      rv = NS_NewURI(getter_AddRefs(uri), mURISpec);
+      if (NS_FAILED(rv)) {
+        return NS_OK;
+      }
+
+      rv = mWalker->mCallback->OnCacheEntryInfo(
         uri, mIdEnhance, mDataSize, mFetchCount,
         mLastModifiedTime, mExpirationTime, mPinned);
+      if (NS_FAILED(rv)) {
+        mWalker->mCancel = true;
+      }
+
       return NS_OK;
     }
 
@@ -432,7 +449,7 @@ private:
           }
         }
 
-        while (true) {
+        while (!mCancel) {
           if (CacheIOThread::YieldAndRerun())
             return NS_OK;
 

netwerk/protocol/about/nsAboutCache.cpp

@@ -51,6 +51,8 @@ nsAboutCache::Channel::Init(nsIURI* aURI, nsILoadInfo* aLoadInfo)
 {
     nsresult rv;
 
+    mCancel = false;
+
     nsCOMPtr<nsIInputStream> inputStream;
     rv = NS_NewPipe(getter_AddRefs(inputStream), getter_AddRefs(mStream),
                     16384, (uint32_t)-1,
@@ -359,7 +361,8 @@ nsAboutCache::Channel::OnCacheEntryInfo(nsIURI *aURI, const nsACString & aIdEnha
                                         bool aPinned)
 {
     // We need mStream for this
-    if (!mStream) {
+    if (!mStream || mCancel) {
+        // Returning a failure from this callback stops the iteration
         return NS_ERROR_FAILURE;
     }
 
@@ -470,8 +473,7 @@ nsAboutCache::Channel::OnCacheEntryInfo(nsIURI *aURI, const nsACString & aIdEnha
     // Entry is done...
     mBuffer.AppendLiteral("  </tr>\n");
 
-    FlushBuffer();
-    return NS_OK;
+    return FlushBuffer();
 }
 
 NS_IMETHODIMP
@@ -503,12 +505,20 @@ nsAboutCache::Channel::OnCacheEntryVisitCompleted()
     return NS_OK;
 }
 
-void
+nsresult
 nsAboutCache::Channel::FlushBuffer()
 {
+    nsresult rv;
+
     uint32_t bytesWritten;
-    mStream->Write(mBuffer.get(), mBuffer.Length(), &bytesWritten);
+    rv = mStream->Write(mBuffer.get(), mBuffer.Length(), &bytesWritten);
     mBuffer.Truncate();
+
+    if (NS_FAILED(rv)) {
+        mCancel = true;
+    }
+
+    return rv;
 }
 
 NS_IMETHODIMP

netwerk/protocol/about/nsAboutCache.h

@@ -64,8 +64,10 @@ protected:
         nsresult VisitStorage(nsACString const & storageName);
 
         // Writes content of mBuffer to mStream and truncates
-        // the buffer.
-        void FlushBuffer();
+        // the buffer.  It may fail when the input stream is closed by canceling
+        // the input stream channel.  It can be used to stop the cache iteration
+        // process.
+        nsresult FlushBuffer();
 
         // Whether we are showing overview status of all available
         // storages.
@@ -75,6 +77,9 @@ protected:
         // been added to the output HTML.
         bool mEntriesHeaderAdded;
 
+        // Cancelation flag
+        bool mCancel;
+
         // The context we are working with.
         nsCOMPtr<nsILoadContextInfo> mLoadInfo;
         nsCString mContextString;