Fix Resource Timing buffer edge cases for WPT

https://bugs.webkit.org/show_bug.cgi?id=193213

Patch by Charles Vazac <cvazac@akamai.com> on 2019-02-28
Reviewed by Youenn Fablet.

LayoutTests/imported/w3c:

* web-platform-tests/resource-timing/buffer-full-add-after-full-event.html:
* web-platform-tests/resource-timing/buffer-full-add-entries-during-callback-that-drop-expected.txt:
* web-platform-tests/resource-timing/buffer-full-add-then-clear-expected.txt:
* web-platform-tests/resource-timing/buffer-full-then-increased-expected.txt:

Source/WebCore:

Test coverage by LayoutTests/imported/w3c/web-platform-tests/resource-timing/buffer*.html

* page/Performance.cpp:
(WebCore::Performance::resourceTimingBufferFullTimerFired): Only dispatch the
resourcetimingbufferfull event if the buffer is still full (as it may have been cleared or
expanded). Also, avoid infinite loops if we aren't able to decrease the number of entries in
the secondary buffer.

Canonical link: https://commits.webkit.org/209500@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@242209 268f45cc-cd09-0410-ab3c-d52691b4dbfc

LayoutTests/http/tests/performance/performance-resource-timing-resourcetimingbufferfull-shrinking-buffer-crash-expected.txt

@@ -19,12 +19,10 @@ performance.setResourceTimingBufferSize(1)
 PASS resourcesAfterShrinkingBuffer = performance.getEntriesByType("resource"); resourcesAfterShrinkingBuffer.length is 2
 PASS resourcesAfterShrinkingBuffer[0] is originalResources[0]
 PASS resourcesAfterShrinkingBuffer[1] is originalResources[1]
-
-Inside resourcetimingbufferfull 2
 PASS performance.clearResourceTimings(); performance.getEntriesByType("resource").length is 0
 
 After resourcetimingbufferfull
-PASS resourcetimingbufferfullEventCount is 2
+PASS resourcetimingbufferfullEventCount is 1
 PASS resourcesAfterClearing = performance.getEntriesByType("resource"); resourcesAfterClearing.length is 1
 PASS resourcesAfterClearing[0].initiatorType is "fetch"
 PASS new URL(resourcesAfterClearing[0].name).search is "?resource=2"

LayoutTests/http/tests/performance/performance-resource-timing-resourcetimingbufferfull-shrinking-buffer-crash.html

@@ -42,12 +42,11 @@
         shouldBe('resourcesAfterShrinkingBuffer = performance.getEntriesByType("resource"); resourcesAfterShrinkingBuffer.length', '2');
         shouldBe('resourcesAfterShrinkingBuffer[0]', 'originalResources[0]');
         shouldBe('resourcesAfterShrinkingBuffer[1]', 'originalResources[1]');
-    } else if (resourcetimingbufferfullEventCount == 2) {
         shouldBe('performance.clearResourceTimings(); performance.getEntriesByType("resource").length', '0');
         setTimeout(() => {
             debug('');
             debug('After resourcetimingbufferfull');
-            shouldBe('resourcetimingbufferfullEventCount', '2');
+            shouldBe('resourcetimingbufferfullEventCount', '1');
             shouldBe('resourcesAfterClearing = performance.getEntriesByType("resource"); resourcesAfterClearing.length', '1');
             shouldBeEqualToString('resourcesAfterClearing[0].initiatorType', 'fetch');
             shouldBeEqualToString('new URL(resourcesAfterClearing[0].name).search', '?resource=2');

LayoutTests/imported/w3c/ChangeLog

@@ -1,3 +1,15 @@
+2019-02-28  Charles Vazac  <cvazac@akamai.com>
+
+        Fix Resource Timing buffer edge cases for WPT
+        https://bugs.webkit.org/show_bug.cgi?id=193213
+
+        Reviewed by Youenn Fablet.
+
+        * web-platform-tests/resource-timing/buffer-full-add-after-full-event.html:
+        * web-platform-tests/resource-timing/buffer-full-add-entries-during-callback-that-drop-expected.txt:
+        * web-platform-tests/resource-timing/buffer-full-add-then-clear-expected.txt:
+        * web-platform-tests/resource-timing/buffer-full-then-increased-expected.txt:
+
 2019-02-26  Youenn Fablet  <youenn@apple.com>
 
         Move service worker response validation from the service worker client to the service worker itself

LayoutTests/imported/w3c/web-platform-tests/resource-timing/buffer-full-add-entries-during-callback-that-drop-expected.txt

@@ -0,0 +1,3 @@
+
+PASS Test that entries synchronously added to the buffer during the callback are dropped 
+

LayoutTests/imported/w3c/web-platform-tests/resource-timing/buffer-full-add-then-clear-expected.txt

@@ -1,6 +1,3 @@
-CONSOLE MESSAGE: line 2659: Error: assert_unreached: resourcetimingbufferfull should not fire Reached unreachable code
 
-Harness Error (FAIL), message = Error: assert_unreached: resourcetimingbufferfull should not fire Reached unreachable code
-
-FAIL Test that if the buffer is cleared after entries were added to the secondary buffer, those entries make it into the primary one assert_equals: the last 3 resources should be in the buffer, since the first one was cleared expected 3 but got 0
+PASS Test that if the buffer is cleared after entries were added to the secondary buffer, those entries make it into the primary one 
 

LayoutTests/imported/w3c/web-platform-tests/resource-timing/buffer-full-then-increased-expected.txt

@@ -1,6 +1,3 @@
-CONSOLE MESSAGE: line 2659: Error: assert_unreached: resourcetimingbufferfull should not fire Reached unreachable code
 
-Harness Error (FAIL), message = Error: assert_unreached: resourcetimingbufferfull should not fire Reached unreachable code
-
-FAIL Test that overflowing the buffer and immediately increasing its limit does not trigger the resourcetimingbufferfull event assert_equals: All resources should be in the buffer, since its size was increased expected 3 but got 1
+PASS Test that overflowing the buffer and immediately increasing its limit does not trigger the resourcetimingbufferfull event 
 

Source/WebCore/ChangeLog

@@ -1,3 +1,18 @@
+2019-02-28  Charles Vazac  <cvazac@akamai.com>
+
+        Fix Resource Timing buffer edge cases for WPT
+        https://bugs.webkit.org/show_bug.cgi?id=193213
+
+        Reviewed by Youenn Fablet.
+
+        Test coverage by LayoutTests/imported/w3c/web-platform-tests/resource-timing/buffer*.html
+
+        * page/Performance.cpp:
+        (WebCore::Performance::resourceTimingBufferFullTimerFired): Only dispatch the
+        resourcetimingbufferfull event if the buffer is still full (as it may have been cleared or
+        expanded). Also, avoid infinite loops if we aren't able to decrease the number of entries in
+        the secondary buffer.
+
 2019-02-28  Takashi Komori  <Takashi.Komori@sony.com>
 
         [Curl] HTTP Body is missing with redirection.

Source/WebCore/page/Performance.cpp

@@ -214,11 +214,15 @@ void Performance::resourceTimingBufferFullTimerFired()
     ASSERT(scriptExecutionContext());
 
     while (!m_backupResourceTimingBuffer.isEmpty()) {
+        auto beforeCount = m_backupResourceTimingBuffer.size();
+
         auto backupBuffer = WTFMove(m_backupResourceTimingBuffer);
         ASSERT(m_backupResourceTimingBuffer.isEmpty());
 
-        m_resourceTimingBufferFullFlag = true;
-        dispatchEvent(Event::create(eventNames().resourcetimingbufferfullEvent, Event::CanBubble::No, Event::IsCancelable::No));
+        if (isResourceTimingBufferFull()) {
+            m_resourceTimingBufferFullFlag = true;
+            dispatchEvent(Event::create(eventNames().resourcetimingbufferfullEvent, Event::CanBubble::No, Event::IsCancelable::No));
+        }
 
         if (m_resourceTimingBufferFullFlag) {
             for (auto& entry : backupBuffer)
@@ -241,6 +245,13 @@ void Performance::resourceTimingBufferFullTimerFired()
             } else
                 m_backupResourceTimingBuffer.append(entry.copyRef());
         }
+
+        auto afterCount = m_backupResourceTimingBuffer.size();
+
+        if (beforeCount <= afterCount) {
+            m_backupResourceTimingBuffer.clear();
+            break;
+        }
     }
     m_waitingForBackupBufferToBeProcessed = false;
 }