void measure()

in litho-core/src/main/java/com/facebook/litho/ComponentTree.java [1111:1224]
103 lines of code
19 McCabe index (conditional complexity)

  void measure(int widthSpec, int heightSpec, int[] measureOutput, boolean forceLayout) {
    assertMainThread();

    mIsMeasuring = true;
    try {
      final boolean needsSyncLayout;
      synchronized (this) {
        if (DEBUG_LOGS) {
          debugLog(
              "StartMeasure",
              "WidthSpec: "
                  + View.MeasureSpec.toString(widthSpec)
                  + ", HeightSpec: "
                  + View.MeasureSpec.toString(heightSpec)
                  + ", isCompatibleWithCommittedLayout: "
                  + isCompatibleSpec(mCommittedLayoutState, widthSpec, heightSpec)
                  + ", isCompatibleWithMainThreadLayout: "
                  + isCompatibleComponentAndSpec(
                      mMainThreadLayoutState,
                      mRoot != null ? mRoot.getId() : INVALID_ID,
                      widthSpec,
                      heightSpec)
                  + ", hasSameSpecs: "
                  + (mMainThreadLayoutState != null
                      && mMainThreadLayoutState.getWidthSpec() == widthSpec
                      && mMainThreadLayoutState.getHeightSpec() == heightSpec));
        }

        if (mCommittedLayoutState != null
            && mCommittedLayoutState != mMainThreadLayoutState
            && isCompatibleSpec(mCommittedLayoutState, widthSpec, heightSpec)) {
          promoteCommittedLayoutStateToUI();
        }

        final boolean hasExactSameSpecs =
            mMainThreadLayoutState != null
                && mMainThreadLayoutState.getWidthSpec() == widthSpec
                && mMainThreadLayoutState.getHeightSpec() == heightSpec;
        final boolean hasSameRootAndEquivalentSpecs =
            isCompatibleComponentAndSpec(
                mMainThreadLayoutState,
                mRoot != null ? mRoot.getId() : INVALID_ID,
                widthSpec,
                heightSpec);
        if (hasExactSameSpecs || hasSameRootAndEquivalentSpecs) {
          measureOutput[0] = mMainThreadLayoutState.getWidth();
          measureOutput[1] = mMainThreadLayoutState.getHeight();
          needsSyncLayout = false;
        } else {
          needsSyncLayout = true;
        }
      }

      if (needsSyncLayout || forceLayout) {
        final Size output = new Size();
        setSizeSpecForMeasure(widthSpec, heightSpec, output, forceLayout);

        // It's possible we don't commit a layout or block on a future on another thread (which will
        // not immediately promote the committed layout state since that needs to happen on the main
        // thread). Ensure we have the latest LayoutState before exiting.
        synchronized (this) {
          if (mReleased) {
            throw new RuntimeException("Tree is released during measure!");
          }
          if (mCommittedLayoutState != mMainThreadLayoutState) {
            promoteCommittedLayoutStateToUI();
          }

          if (mMainThreadLayoutState != null) {
            measureOutput[0] = mMainThreadLayoutState.getWidth();
            measureOutput[1] = mMainThreadLayoutState.getHeight();
          } else {
            measureOutput[0] = output.width;
            measureOutput[1] = output.height;

            ComponentsReporter.emitMessage(
                ComponentsReporter.LogLevel.ERROR,
                "NullLayoutStateInMeasure",
                "Measure Specs: ["
                    + View.MeasureSpec.toString(widthSpec)
                    + ", "
                    + View.MeasureSpec.toString(heightSpec)
                    + "], Current Specs: ["
                    + View.MeasureSpec.toString(mWidthSpec)
                    + ", "
                    + View.MeasureSpec.toString(mHeightSpec)
                    + "], Output [W: "
                    + output.width
                    + ", H:"
                    + output.height
                    + "], Last Layout Source: "
                    + LayoutState.layoutSourceToString(mLastLayoutSource));
          }
        }
      } else {
        setSizeSpecForMeasureAsync(widthSpec, heightSpec);
      }
    } finally {
      mIsMeasuring = false;
    }

    if (DEBUG_LOGS) {
      debugLog(
          "FinishMeasure",
          "WidthSpec: "
              + View.MeasureSpec.toString(widthSpec)
              + ", HeightSpec: "
              + View.MeasureSpec.toString(heightSpec)
              + ", OutWidth: "
              + measureOutput[0]
              + ", OutHeight: "
              + measureOutput[1]);
    }
  }