1 files changed, 103 insertions, 0 deletions
diff --git a/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/state/transforms/PropertyChangeTransform.java b/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/state/transforms/PropertyChangeTransform.java
new file mode 100644
index 000000000..276f6f49b
--- /dev/null
+++ b/eclipse/plugins/com.android.ide.eclipse.gldebugger/src/com/android/ide/eclipse/gltrace/state/transforms/PropertyChangeTransform.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.ide.eclipse.gltrace.state.transforms;
+
+import com.android.ide.eclipse.gltrace.state.IGLProperty;
+
+/**
+ * A PropertyChangeTransform object provides the ability to alter the value of a
+ * single GL State variable. An optional predicate provides the ability to perform
+ * the change only if the predicate succeeds.
+ */
+public class PropertyChangeTransform implements IStateTransform {
+    private final IGLPropertyAccessor mAccessor;
+    private final Object mNewValue;
+    private final IPredicate mPredicate;
+    private Object mOldValue;
+
+    /**
+     * Construct a state transform that will extract the property using the accessor,
+     * and modify its value to the provided value.
+     */
+    PropertyChangeTransform(IGLPropertyAccessor accessor, Object newValue) {
+        this(accessor, newValue, null);
+    }
+
+    /**
+     * Construct a state transform that will extract the property using the accessor,
+     * check if the predicate function accepts the current value, and if so modify its
+     * value to the provided value.
+     */
+    public PropertyChangeTransform(IGLPropertyAccessor accessor, Object newValue,
+            IPredicate predicate) {
+        mAccessor = accessor;
+        mNewValue = newValue;
+        mPredicate = predicate;
+        mOldValue = null;
+    }
+
+    /** Apply the state transformation on the given OpenGL state. */
+    @Override
+    public void apply(IGLProperty state) {
+        IGLProperty property = mAccessor.getProperty(state);
+
+        assert mOldValue == null : "Transform cannot be applied multiple times";
+        if (mPredicate != null) {
+            // if predicate is not null, then first check if the current value
+            // passes the predicate function.
+            if (!mPredicate.apply(property.getValue())) {
+                return;
+            }
+        }
+
+        if (property != null) {
+            mOldValue = property.getValue();
+            property.setValue(mNewValue);
+        } else {
+            throw new RuntimeException("No such property: " + mAccessor.getPath());
+        }
+    }
+
+    /**
+     * Reverses the effect of this state transform. It restores the property's value to the same
+     * state as it was before this transformation was applied. If this transform was never
+     * {@link #apply(IGLProperty)}'ed, then performing a revert has no effect.
+     */
+    @Override
+    public void revert(IGLProperty state) {
+        if (mOldValue != null) {
+            IGLProperty property = mAccessor.getProperty(state);
+            property.setValue(mOldValue);
+            mOldValue = null;
+        }
+    }
+
+    /** Gets the property that will be affected by applying this transformation. */
+    @Override
+    public IGLProperty getChangedProperty(IGLProperty state) {
+        if (mPredicate != null) {
+            Object value = mOldValue == null ? mNewValue : mOldValue;
+            if (!mPredicate.apply(value)) {
+                // if the value doesn't match the predicate, then this property
+                // is not altered.
+                return null;
+            }
+        }
+
+        return mAccessor.getProperty(state);
+    }
+}