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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "cc/input/main_thread_scrolling_reason.h"
#include <string>
#include "base/strings/string_util.h"
#include "base/trace_event/traced_value.h"
namespace cc {
std::string MainThreadScrollingReason::AsText(uint32_t reasons) {
base::trace_event::TracedValueJSON traced_value;
AddToTracedValue(reasons, traced_value);
std::string result = traced_value.ToJSON();
// Remove '{main_thread_scrolling_reasons:[', ']}', and any '"' chars.
size_t array_start_pos = result.find('[');
size_t array_end_pos = result.find(']');
result =
result.substr(array_start_pos + 1, array_end_pos - array_start_pos - 1);
std::erase(result, '\"');
// Add spaces after all commas.
base::ReplaceChars(result, ",", ", ", &result);
return result;
}
void MainThreadScrollingReason::AddToTracedValue(
uint32_t reasons,
base::trace_event::TracedValue& traced_value) {
traced_value.BeginArray("main_thread_scrolling_reasons");
#define ADD_REASON(reason, string) \
do \
if (reasons & reason) { \
traced_value.AppendString(string); \
reasons &= ~reason; \
} \
while (false)
ADD_REASON(kHasBackgroundAttachmentFixedObjects,
"Has background-attachment:fixed");
ADD_REASON(kNotOpaqueForTextAndLCDText, "Not opaque for text and LCD text");
ADD_REASON(kPreferNonCompositedScrolling, "Prefer non-composited scrolling");
ADD_REASON(kBackgroundNeedsRepaintOnScroll,
"Background needs repaint on scroll");
ADD_REASON(kScrollbarScrolling, "Scrollbar scrolling");
ADD_REASON(kMainThreadScrollHitTestRegion,
"Main thread scroll hit test region");
ADD_REASON(kFailedHitTest, "Failed hit test");
ADD_REASON(kPopupNoThreadedInput,
"Popup scrolling (no threaded input handler)");
ADD_REASON(kWheelEventHandlerRegion, "Wheel event handler region");
ADD_REASON(kTouchEventHandlerRegion, "Touch event handler region");
#undef ADD_REASON
DCHECK_EQ(reasons, kNotScrollingOnMain);
traced_value.EndArray();
}
int MainThreadScrollingReason::BucketIndexForTesting(uint32_t reason) {
// These two values are already bucket indices.
DCHECK_NE(reason, kNotScrollingOnMain);
DCHECK_NE(reason, kScrollingOnMainForAnyReason);
int index = 0;
while (reason >>= 1)
++index;
DCHECK_NE(index, 0);
return index;
}
} // namespace cc
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