Don't store empty objects on SF traces

Proto3 doesn't store default values for object, however, it stored the
object start-end tags if an empty object was created.

Do not create objects when they are empty

Test: Flash a device. Record SF trace. Open them in the new winscope
version with "display defaults" unchecked. Check if there are no empty
objects

Change-Id: I3f48047e43e9c62c572d5b83e63a0f96527ef146
diff --git a/services/surfaceflinger/LayerProtoHelper.cpp b/services/surfaceflinger/LayerProtoHelper.cpp
index 3289e8f..02383a6 100644
--- a/services/surfaceflinger/LayerProtoHelper.cpp
+++ b/services/surfaceflinger/LayerProtoHelper.cpp
@@ -18,53 +18,106 @@
 
 namespace android {
 namespace surfaceflinger {
-void LayerProtoHelper::writeToProto(const Region& region, RegionProto* regionProto) {
+
+void LayerProtoHelper::writePositionToProto(const float x, const float y,
+                                            std::function<PositionProto*()> getPositionProto) {
+    if (x != 0 || y != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        PositionProto* position = getPositionProto();
+        position->set_x(x);
+        position->set_y(y);
+    }
+}
+
+void LayerProtoHelper::writeSizeToProto(const uint32_t w, const uint32_t h,
+                                        std::function<SizeProto*()> getSizeProto) {
+    if (w != 0 || h != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        SizeProto* size = getSizeProto();
+        size->set_w(w);
+        size->set_h(h);
+    }
+}
+
+void LayerProtoHelper::writeToProto(const Region& region,
+                                    std::function<RegionProto*()> getRegionProto) {
+    if (region.isEmpty()) {
+        return;
+    }
+
     Region::const_iterator head = region.begin();
     Region::const_iterator const tail = region.end();
+    // Use a lambda do avoid writing the object header when the object is empty
+    RegionProto* regionProto = getRegionProto();
     uint64_t address = reinterpret_cast<uint64_t>(&region);
     regionProto->set_id(address);
     while (head != tail) {
-        RectProto* rectProto = regionProto->add_rect();
-        writeToProto(*head, rectProto);
+        std::function<RectProto*()> getProtoRect = [&]() { return regionProto->add_rect(); };
+        writeToProto(*head, getProtoRect);
         head++;
     }
 }
 
-void LayerProtoHelper::writeToProto(const Rect& rect, RectProto* rectProto) {
-    rectProto->set_left(rect.left);
-    rectProto->set_top(rect.top);
-    rectProto->set_bottom(rect.bottom);
-    rectProto->set_right(rect.right);
+void LayerProtoHelper::writeToProto(const Rect& rect, std::function<RectProto*()> getRectProto) {
+    if (rect.left != 0 || rect.right != 0 || rect.top != 0 || rect.bottom != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        RectProto* rectProto = getRectProto();
+        rectProto->set_left(rect.left);
+        rectProto->set_top(rect.top);
+        rectProto->set_bottom(rect.bottom);
+        rectProto->set_right(rect.right);
+    }
 }
 
-void LayerProtoHelper::writeToProto(const FloatRect& rect, FloatRectProto* rectProto) {
-    rectProto->set_left(rect.left);
-    rectProto->set_top(rect.top);
-    rectProto->set_bottom(rect.bottom);
-    rectProto->set_right(rect.right);
+void LayerProtoHelper::writeToProto(const FloatRect& rect,
+                                    std::function<FloatRectProto*()> getFloatRectProto) {
+    if (rect.left != 0 || rect.right != 0 || rect.top != 0 || rect.bottom != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        FloatRectProto* rectProto = getFloatRectProto();
+        rectProto->set_left(rect.left);
+        rectProto->set_top(rect.top);
+        rectProto->set_bottom(rect.bottom);
+        rectProto->set_right(rect.right);
+    }
 }
 
-void LayerProtoHelper::writeToProto(const half4 color, ColorProto* colorProto) {
-    colorProto->set_r(color.r);
-    colorProto->set_g(color.g);
-    colorProto->set_b(color.b);
-    colorProto->set_a(color.a);
+void LayerProtoHelper::writeToProto(const half4 color, std::function<ColorProto*()> getColorProto) {
+    if (color.r != 0 || color.g != 0 || color.b != 0 || color.a != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        ColorProto* colorProto = getColorProto();
+        colorProto->set_r(color.r);
+        colorProto->set_g(color.g);
+        colorProto->set_b(color.b);
+        colorProto->set_a(color.a);
+    }
 }
 
 void LayerProtoHelper::writeToProto(const ui::Transform& transform,
                                     TransformProto* transformProto) {
-    transformProto->set_dsdx(transform[0][0]);
-    transformProto->set_dtdx(transform[0][1]);
-    transformProto->set_dsdy(transform[1][0]);
-    transformProto->set_dtdy(transform[1][1]);
+    const uint32_t type = transform.getType();
+    transformProto->set_type(type);
+
+    if (type &
+        (ui::Transform::SCALE | ui::Transform::ROTATE | ui::Transform::TRANSLATE |
+         ui::Transform::UNKNOWN)) {
+        transformProto->set_dsdx(transform[0][0]);
+        transformProto->set_dtdx(transform[0][1]);
+        transformProto->set_dsdy(transform[1][0]);
+        transformProto->set_dtdy(transform[1][1]);
+    }
 }
 
 void LayerProtoHelper::writeToProto(const sp<GraphicBuffer>& buffer,
-                                    ActiveBufferProto* activeBufferProto) {
-    activeBufferProto->set_width(buffer->getWidth());
-    activeBufferProto->set_height(buffer->getHeight());
-    activeBufferProto->set_stride(buffer->getStride());
-    activeBufferProto->set_format(buffer->format);
+                                    std::function<ActiveBufferProto*()> getActiveBufferProto) {
+    if (buffer->getWidth() != 0 || buffer->getHeight() != 0 || buffer->getStride() != 0 ||
+        buffer->format != 0) {
+        // Use a lambda do avoid writing the object header when the object is empty
+        ActiveBufferProto* activeBufferProto = getActiveBufferProto();
+        activeBufferProto->set_width(buffer->getWidth());
+        activeBufferProto->set_height(buffer->getHeight());
+        activeBufferProto->set_stride(buffer->getStride());
+        activeBufferProto->set_format(buffer->format);
+    }
 }
 
 } // namespace surfaceflinger