1/*
2 * Copyright (C) 2015 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 */
16package android.databinding.annotationprocessor;
17
18import android.databinding.BindingAdapter;
19import android.databinding.BindingBuildInfo;
20import android.databinding.BindingConversion;
21import android.databinding.BindingMethod;
22import android.databinding.BindingMethods;
23import android.databinding.InverseBindingAdapter;
24import android.databinding.InverseBindingMethod;
25import android.databinding.InverseBindingMethods;
26import android.databinding.Untaggable;
27import android.databinding.tool.reflection.ModelAnalyzer;
28import android.databinding.tool.store.SetterStore;
29import android.databinding.tool.util.L;
30import android.databinding.tool.util.Preconditions;
31
32import java.io.IOException;
33import java.util.HashSet;
34import java.util.List;
35
36import javax.annotation.processing.ProcessingEnvironment;
37import javax.annotation.processing.RoundEnvironment;
38import javax.lang.model.element.Element;
39import javax.lang.model.element.ElementKind;
40import javax.lang.model.element.ExecutableElement;
41import javax.lang.model.element.Modifier;
42import javax.lang.model.element.TypeElement;
43import javax.lang.model.element.VariableElement;
44import javax.lang.model.type.MirroredTypeException;
45import javax.lang.model.type.TypeKind;
46import javax.lang.model.type.TypeMirror;
47import javax.lang.model.util.Elements;
48import javax.lang.model.util.Types;
49
50public class ProcessMethodAdapters extends ProcessDataBinding.ProcessingStep {
51    private final static String INVERSE_BINDING_EVENT_ATTR_SUFFIX = "AttrChanged";
52
53    public ProcessMethodAdapters() {
54    }
55
56    @Override
57    public boolean onHandleStep(RoundEnvironment roundEnv,
58            ProcessingEnvironment processingEnvironment, BindingBuildInfo buildInfo) {
59        L.d("processing adapters");
60        final ModelAnalyzer modelAnalyzer = ModelAnalyzer.getInstance();
61        Preconditions.checkNotNull(modelAnalyzer, "Model analyzer should be"
62                + " initialized first");
63        SetterStore store = SetterStore.get(modelAnalyzer);
64        clearIncrementalClasses(roundEnv, store);
65
66        addBindingAdapters(roundEnv, processingEnvironment, store);
67        addRenamed(roundEnv, store);
68        addConversions(roundEnv, store);
69        addUntaggable(roundEnv, store);
70        addInverseAdapters(roundEnv, processingEnvironment, store);
71        addInverseMethods(roundEnv, store);
72
73        try {
74            store.write(buildInfo.modulePackage(), processingEnvironment);
75        } catch (IOException e) {
76            L.e(e, "Could not write BindingAdapter intermediate file.");
77        }
78        return true;
79    }
80
81    @Override
82    public void onProcessingOver(RoundEnvironment roundEnvironment,
83            ProcessingEnvironment processingEnvironment, BindingBuildInfo buildInfo) {
84
85    }
86
87    private void addBindingAdapters(RoundEnvironment roundEnv, ProcessingEnvironment
88            processingEnv, SetterStore store) {
89        for (Element element : AnnotationUtil
90                .getElementsAnnotatedWith(roundEnv, BindingAdapter.class)) {
91            if (element.getKind() != ElementKind.METHOD ||
92                    !element.getModifiers().contains(Modifier.PUBLIC)) {
93                L.e(element, "@BindingAdapter on invalid element: %s", element);
94                continue;
95            }
96            BindingAdapter bindingAdapter = element.getAnnotation(BindingAdapter.class);
97
98            ExecutableElement executableElement = (ExecutableElement) element;
99            List<? extends VariableElement> parameters = executableElement.getParameters();
100            if (bindingAdapter.value().length == 0) {
101                L.e(element, "@BindingAdapter requires at least one attribute. %s",
102                        element);
103                continue;
104            }
105
106            final boolean takesComponent = takesComponent(executableElement, processingEnv);
107            final int startIndex = 1 + (takesComponent ? 1 : 0);
108            final int numAttributes = bindingAdapter.value().length;
109            final int numAdditionalArgs = parameters.size() - startIndex;
110            if (numAdditionalArgs == (2 * numAttributes)) {
111                // This BindingAdapter takes old and new values. Make sure they are properly ordered
112                Types typeUtils = processingEnv.getTypeUtils();
113                boolean hasParameterError = false;
114                for (int i = startIndex; i < numAttributes + startIndex; i++) {
115                    if (!typeUtils.isSameType(parameters.get(i).asType(),
116                            parameters.get(i + numAttributes).asType())) {
117                        L.e(executableElement, "BindingAdapter %s: old values should be followed " +
118                                "by new values. Parameter %d must be the same type as parameter " +
119                                "%d.", executableElement, i + 1, i + numAttributes + 1);
120                        hasParameterError = true;
121                        break;
122                    }
123                }
124                if (hasParameterError) {
125                    continue;
126                }
127            } else if (numAdditionalArgs != numAttributes) {
128                L.e(element, "@BindingAdapter %s has %d attributes and %d value " +
129                        "parameters. There should be %d or %d value parameters.",
130                        executableElement, numAttributes, numAdditionalArgs, numAttributes,
131                        numAttributes * 2);
132                continue;
133            }
134            warnAttributeNamespaces(element, bindingAdapter.value());
135            try {
136                if (numAttributes == 1) {
137                    final String attribute = bindingAdapter.value()[0];
138                    store.addBindingAdapter(processingEnv, attribute, executableElement,
139                            takesComponent);
140                } else {
141                    store.addBindingAdapter(processingEnv, bindingAdapter.value(),
142                            executableElement, takesComponent, bindingAdapter.requireAll());
143                }
144            } catch (IllegalArgumentException e) {
145                L.e(element, "@BindingAdapter for duplicate View and parameter type: %s", element);
146            }
147        }
148    }
149
150    private static boolean takesComponent(ExecutableElement executableElement,
151            ProcessingEnvironment processingEnvironment) {
152        List<? extends VariableElement> parameters = executableElement.getParameters();
153        Elements elementUtils = processingEnvironment.getElementUtils();
154        TypeMirror viewElement = elementUtils.getTypeElement("android.view.View").asType();
155        if (parameters.size() < 2) {
156            return false; // Validation will fail in the caller
157        }
158        TypeMirror parameter1 = parameters.get(0).asType();
159        Types typeUtils = processingEnvironment.getTypeUtils();
160        if (parameter1.getKind() == TypeKind.DECLARED &&
161                typeUtils.isAssignable(parameter1, viewElement)) {
162            return false; // first parameter is a View
163        }
164        if (parameters.size() < 3) {
165            TypeMirror viewStubProxy = elementUtils.
166                    getTypeElement("android.databinding.ViewStubProxy").asType();
167            if (!typeUtils.isAssignable(parameter1, viewStubProxy)) {
168                L.e(executableElement, "@BindingAdapter %s is applied to a method that has two " +
169                        "parameters, the first must be a View type", executableElement);
170            }
171            return false;
172        }
173        TypeMirror parameter2 = parameters.get(1).asType();
174        if (typeUtils.isAssignable(parameter2, viewElement)) {
175            return true; // second parameter is a View
176        }
177        L.e(executableElement, "@BindingAdapter %s is applied to a method that doesn't take a " +
178                "View subclass as the first or second parameter. When a BindingAdapter uses a " +
179                "DataBindingComponent, the component parameter is first and the View " +
180                "parameter is second, otherwise the View parameter is first.",
181                executableElement);
182        return false;
183    }
184
185    private static void warnAttributeNamespace(Element element, String attribute) {
186        if (attribute.contains(":") && !attribute.startsWith("android:")) {
187            L.w(element, "Application namespace for attribute %s will be ignored.", attribute);
188        }
189    }
190
191    private static void warnAttributeNamespaces(Element element, String[] attributes) {
192        for (String attribute : attributes) {
193            warnAttributeNamespace(element, attribute);
194        }
195    }
196
197    private void addRenamed(RoundEnvironment roundEnv, SetterStore store) {
198        for (Element element : AnnotationUtil
199                .getElementsAnnotatedWith(roundEnv, BindingMethods.class)) {
200            BindingMethods bindingMethods = element.getAnnotation(BindingMethods.class);
201
202            for (BindingMethod bindingMethod : bindingMethods.value()) {
203                final String attribute = bindingMethod.attribute();
204                final String method = bindingMethod.method();
205                warnAttributeNamespace(element, attribute);
206                String type;
207                try {
208                    type = bindingMethod.type().getCanonicalName();
209                } catch (MirroredTypeException e) {
210                    type = e.getTypeMirror().toString();
211                }
212                store.addRenamedMethod(attribute, type, method, (TypeElement) element);
213            }
214        }
215    }
216
217    private void addConversions(RoundEnvironment roundEnv, SetterStore store) {
218        for (Element element : AnnotationUtil
219                .getElementsAnnotatedWith(roundEnv, BindingConversion.class)) {
220            if (element.getKind() != ElementKind.METHOD ||
221                    !element.getModifiers().contains(Modifier.STATIC) ||
222                    !element.getModifiers().contains(Modifier.PUBLIC)) {
223                L.e(element, "@BindingConversion is only allowed on public static methods %s",
224                        element);
225                continue;
226            }
227
228            ExecutableElement executableElement = (ExecutableElement) element;
229            if (executableElement.getParameters().size() != 1) {
230                L.e(element, "@BindingConversion method should have one parameter %s", element);
231                continue;
232            }
233            if (executableElement.getReturnType().getKind() == TypeKind.VOID) {
234                L.e(element, "@BindingConversion method must return a value %s", element);
235                continue;
236            }
237            store.addConversionMethod(executableElement);
238        }
239    }
240
241    private void addInverseAdapters(RoundEnvironment roundEnv,
242            ProcessingEnvironment processingEnv, SetterStore store) {
243        for (Element element : AnnotationUtil
244                .getElementsAnnotatedWith(roundEnv, InverseBindingAdapter.class)) {
245            if (!element.getModifiers().contains(Modifier.PUBLIC)) {
246                L.e(element, "@InverseBindingAdapter must be associated with a public method");
247                continue;
248            }
249            ExecutableElement executableElement = (ExecutableElement) element;
250            if (executableElement.getReturnType().getKind() == TypeKind.VOID) {
251                L.e(element, "@InverseBindingAdapter must have a non-void return type");
252                continue;
253            }
254            final InverseBindingAdapter inverseBindingAdapter =
255                    executableElement.getAnnotation(InverseBindingAdapter.class);
256            final String attribute = inverseBindingAdapter.attribute();
257            warnAttributeNamespace(element, attribute);
258            final String event = inverseBindingAdapter.event().isEmpty()
259                    ? inverseBindingAdapter.attribute() + INVERSE_BINDING_EVENT_ATTR_SUFFIX
260                    : inverseBindingAdapter.event();
261            warnAttributeNamespace(element, event);
262            final boolean takesComponent = takesComponent(executableElement, processingEnv);
263            final int expectedArgs = takesComponent ? 2 : 1;
264            final int numParameters = executableElement.getParameters().size();
265            if (numParameters != expectedArgs) {
266                L.e(element, "@InverseBindingAdapter %s takes %s parameters, but %s parameters " +
267                        "were expected", element, numParameters, expectedArgs);
268                continue;
269            }
270            try {
271                store.addInverseAdapter(processingEnv, attribute, event, executableElement,
272                        takesComponent);
273            } catch (IllegalArgumentException e) {
274                L.e(element, "@InverseBindingAdapter for duplicate View and parameter type: %s",
275                        element);
276            }
277        }
278    }
279
280    private void addInverseMethods(RoundEnvironment roundEnv, SetterStore store) {
281        for (Element element : AnnotationUtil
282                .getElementsAnnotatedWith(roundEnv, InverseBindingMethods.class)) {
283            InverseBindingMethods bindingMethods =
284                    element.getAnnotation(InverseBindingMethods.class);
285
286            for (InverseBindingMethod bindingMethod : bindingMethods.value()) {
287                final String attribute = bindingMethod.attribute();
288                final String method = bindingMethod.method();
289                final String event = bindingMethod.event().isEmpty()
290                        ? bindingMethod.attribute() + INVERSE_BINDING_EVENT_ATTR_SUFFIX
291                        : bindingMethod.event();
292                warnAttributeNamespace(element, attribute);
293                warnAttributeNamespace(element, event);
294                String type;
295                try {
296                    type = bindingMethod.type().getCanonicalName();
297                } catch (MirroredTypeException e) {
298                    type = e.getTypeMirror().toString();
299                }
300                store.addInverseMethod(attribute, event, type, method, (TypeElement) element);
301            }
302        }
303    }
304
305    private void addUntaggable(RoundEnvironment roundEnv, SetterStore store) {
306        for (Element element : AnnotationUtil.
307                getElementsAnnotatedWith(roundEnv, Untaggable.class)) {
308            Untaggable untaggable = element.getAnnotation(Untaggable.class);
309            store.addUntaggableTypes(untaggable.value(), (TypeElement) element);
310        }
311    }
312
313    private void clearIncrementalClasses(RoundEnvironment roundEnv, SetterStore store) {
314        HashSet<String> classes = new HashSet<String>();
315
316        for (Element element : AnnotationUtil
317                .getElementsAnnotatedWith(roundEnv, BindingAdapter.class)) {
318            TypeElement containingClass = (TypeElement) element.getEnclosingElement();
319            classes.add(containingClass.getQualifiedName().toString());
320        }
321        for (Element element : AnnotationUtil
322                .getElementsAnnotatedWith(roundEnv, BindingMethods.class)) {
323            classes.add(((TypeElement) element).getQualifiedName().toString());
324        }
325        for (Element element : AnnotationUtil
326                .getElementsAnnotatedWith(roundEnv, BindingConversion.class)) {
327            classes.add(((TypeElement) element.getEnclosingElement()).getQualifiedName().
328                    toString());
329        }
330        for (Element element : AnnotationUtil.
331                getElementsAnnotatedWith(roundEnv, Untaggable.class)) {
332            classes.add(((TypeElement) element).getQualifiedName().toString());
333        }
334        store.clear(classes);
335    }
336}
337