1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.databinding.tool.expr;
18
19import android.databinding.tool.CallbackWrapper;
20import android.databinding.tool.reflection.ModelAnalyzer;
21import android.databinding.tool.reflection.ModelClass;
22import android.databinding.tool.reflection.ModelMethod;
23import android.databinding.tool.solver.ExecutionPath;
24import android.databinding.tool.util.Preconditions;
25import android.databinding.tool.writer.KCode;
26import android.databinding.tool.writer.LayoutBinderWriterKt;
27
28import java.util.Collections;
29import java.util.List;
30import java.util.concurrent.atomic.AtomicInteger;
31
32public class LambdaExpr extends Expr {
33    private static AtomicInteger sIdCounter = new AtomicInteger();
34    private final int mId = sIdCounter.incrementAndGet();
35    private CallbackWrapper mCallbackWrapper;
36    // set when Binding resolves the receiver
37    private final CallbackExprModel mCallbackExprModel;
38    private int mCallbackId;
39    private ExecutionPath mExecutionPath;
40
41    public LambdaExpr(Expr expr, CallbackExprModel callbackExprModel) {
42        super(expr);
43        mCallbackExprModel = callbackExprModel;
44    }
45
46    public Expr getExpr() {
47        return getChildren().get(0);
48    }
49
50    public CallbackExprModel getCallbackExprModel() {
51        return mCallbackExprModel;
52    }
53
54    @Override
55    protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
56        Preconditions.checkNotNull(mCallbackWrapper, "Lambda expression must be resolved to its"
57                + " setter first to get the type.");
58        return mCallbackWrapper.klass;
59    }
60
61    @Override
62    protected List<Dependency> constructDependencies() {
63        return Collections.emptyList();
64    }
65
66    public CallbackWrapper getCallbackWrapper() {
67        return mCallbackWrapper;
68    }
69
70    @Override
71    public Expr resolveListeners(ModelClass valueType, Expr parent) {
72        return this;
73    }
74
75    @Override
76    protected String computeUniqueKey() {
77        return "callback" + mId;
78    }
79
80    @Override
81    public boolean isDynamic() {
82        return false;
83    }
84
85    @Override
86    protected KCode generateCode() {
87        Preconditions
88                .checkNotNull(mCallbackWrapper, "Cannot find the callback method for %s", this);
89        KCode code = new KCode("");
90        final int minApi = mCallbackWrapper.getMinApi();
91        final String fieldName = LayoutBinderWriterKt.getFieldName(this);
92        if (minApi > 1) {
93            code.app("(getBuildSdkInt() < " + minApi + " ? null : ").app(fieldName).app(")");
94        } else {
95            code.app(fieldName);
96        }
97        return code;
98    }
99
100    @Override
101    public Expr cloneToModel(ExprModel model) {
102        return model.lambdaExpr(getExpr().cloneToModel(model), (CallbackExprModel) model);
103    }
104
105    public String generateConstructor() {
106        return getCallbackWrapper().constructForIdentifier(mCallbackId);
107    }
108
109    @Override
110    public void markAsUsed() {
111        super.markAsUsed();
112    }
113
114    @Override
115    protected String getInvertibleError() {
116        return "Lambda expressions cannot be inverted";
117    }
118
119    @Override
120    public List<ExecutionPath> toExecutionPath(List<ExecutionPath> paths) {
121        // i'm not involved.
122        throw new UnsupportedOperationException("should not call toExecutionPath on a lambda"
123                + " expression");
124    }
125
126    public final ExecutionPath getExecutionPath() {
127        return mExecutionPath;
128    }
129
130    public int getCallbackId() {
131        return mCallbackId;
132    }
133
134    public void setup(ModelClass klass, ModelMethod method, int callbackId) {
135        mCallbackId = callbackId;
136        mCallbackWrapper = getModel().callbackWrapper(klass, method);
137        // now register the arguments as variables.
138        final ModelClass[] parameterTypes = method.getParameterTypes();
139        final List<CallbackArgExpr> args = mCallbackExprModel.getArguments();
140        if (parameterTypes.length == args.size()) {
141            for (int i = 0; i < parameterTypes.length; i++) {
142                args.get(i).setClassFromCallback(parameterTypes[i]);
143            }
144        }
145        // first convert to execution path because we may add additional expressions
146        mExecutionPath = ExecutionPath.createRoot();
147        getExpr().toExecutionPath(mExecutionPath);
148        mCallbackExprModel.seal();
149    }
150}
151