1 /* 2 * Copyright (c) 2018 Uber Technologies, Inc. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a copy 5 * of this software and associated documentation files (the "Software"), to deal 6 * in the Software without restriction, including without limitation the rights 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 8 * copies of the Software, and to permit persons to whom the Software is 9 * furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 20 * THE SOFTWARE. 21 */ 22 package com.uber.nullaway.handlers; 23 24 import static com.uber.nullaway.ASTHelpersBackports.getEnclosedElements; 25 26 import com.google.errorprone.VisitorState; 27 import com.google.errorprone.suppliers.Supplier; 28 import com.google.errorprone.suppliers.Suppliers; 29 import com.sun.source.tree.ClassTree; 30 import com.sun.tools.javac.code.Symbol; 31 import com.sun.tools.javac.code.Type; 32 import com.sun.tools.javac.code.Types; 33 import com.uber.nullaway.NullAway; 34 import com.uber.nullaway.Nullness; 35 import com.uber.nullaway.annotations.Initializer; 36 import com.uber.nullaway.dataflow.AccessPath; 37 import com.uber.nullaway.dataflow.AccessPathNullnessPropagation; 38 import java.util.Objects; 39 import java.util.Optional; 40 import javax.annotation.Nullable; 41 import javax.lang.model.element.Element; 42 import javax.lang.model.element.ElementKind; 43 import org.checkerframework.nullaway.dataflow.cfg.node.MethodInvocationNode; 44 import org.checkerframework.nullaway.dataflow.cfg.node.Node; 45 46 /** 47 * Handler to better handle {@code isSetXXXX()} methods in code generated by Apache Thrift. With 48 * this handler, we learn appropriate nullability facts about the relevant property from these 49 * calls. 50 */ 51 public class ApacheThriftIsSetHandler extends BaseNoOpHandler { 52 53 private static final String TBASE_NAME = "org.apache.thrift.TBase"; 54 55 private static final Supplier<Type> TBASE_TYPE_SUPPLIER = Suppliers.typeFromString(TBASE_NAME); 56 57 private Optional<Type> tbaseType; 58 59 /** 60 * This method is annotated {@code @Initializer} since it will be invoked when the first class is 61 * processed, before any other handler methods 62 */ 63 @Initializer 64 @Override onMatchTopLevelClass( NullAway analysis, ClassTree tree, VisitorState state, Symbol.ClassSymbol classSymbol)65 public void onMatchTopLevelClass( 66 NullAway analysis, ClassTree tree, VisitorState state, Symbol.ClassSymbol classSymbol) { 67 if (tbaseType == null) { 68 tbaseType = 69 Optional.ofNullable(TBASE_TYPE_SUPPLIER.get(state)).map(state.getTypes()::erasure); 70 } 71 } 72 73 @Override onDataflowVisitMethodInvocation( MethodInvocationNode node, Symbol.MethodSymbol symbol, VisitorState state, AccessPath.AccessPathContext apContext, AccessPathNullnessPropagation.SubNodeValues inputs, AccessPathNullnessPropagation.Updates thenUpdates, AccessPathNullnessPropagation.Updates elseUpdates, AccessPathNullnessPropagation.Updates bothUpdates)74 public NullnessHint onDataflowVisitMethodInvocation( 75 MethodInvocationNode node, 76 Symbol.MethodSymbol symbol, 77 VisitorState state, 78 AccessPath.AccessPathContext apContext, 79 AccessPathNullnessPropagation.SubNodeValues inputs, 80 AccessPathNullnessPropagation.Updates thenUpdates, 81 AccessPathNullnessPropagation.Updates elseUpdates, 82 AccessPathNullnessPropagation.Updates bothUpdates) { 83 if (thriftIsSetCall(symbol, state.getTypes())) { 84 String methodName = symbol.getSimpleName().toString(); 85 // remove "isSet" 86 String capPropName = methodName.substring(5); 87 if (capPropName.length() > 0) { 88 // build access paths for the getter and the field access, and 89 // make them nonnull in the thenUpdates 90 FieldAndGetterElements fieldAndGetter = getFieldAndGetterForProperty(symbol, capPropName); 91 Node base = node.getTarget().getReceiver(); 92 updateNonNullAPsForElement(thenUpdates, fieldAndGetter.fieldElem, base, apContext); 93 updateNonNullAPsForElement(thenUpdates, fieldAndGetter.getterElem, base, apContext); 94 } 95 } 96 return NullnessHint.UNKNOWN; 97 } 98 updateNonNullAPsForElement( AccessPathNullnessPropagation.Updates updates, @Nullable Element elem, Node base, AccessPath.AccessPathContext apContext)99 private void updateNonNullAPsForElement( 100 AccessPathNullnessPropagation.Updates updates, 101 @Nullable Element elem, 102 Node base, 103 AccessPath.AccessPathContext apContext) { 104 if (elem != null) { 105 AccessPath ap = AccessPath.fromBaseAndElement(base, elem, apContext); 106 if (ap != null) { 107 updates.set(ap, Nullness.NONNULL); 108 } 109 } 110 } 111 112 private static final class FieldAndGetterElements { 113 114 @Nullable final Element fieldElem; 115 116 @Nullable final Element getterElem; 117 FieldAndGetterElements(@ullable Element fieldElem, @Nullable Element getterElem)118 public FieldAndGetterElements(@Nullable Element fieldElem, @Nullable Element getterElem) { 119 this.fieldElem = fieldElem; 120 this.getterElem = getterElem; 121 } 122 123 @Override equals(Object o)124 public boolean equals(Object o) { 125 if (this == o) { 126 return true; 127 } 128 if (o == null || getClass() != o.getClass()) { 129 return false; 130 } 131 FieldAndGetterElements that = (FieldAndGetterElements) o; 132 return Objects.equals(fieldElem, that.fieldElem) 133 && Objects.equals(getterElem, that.getterElem); 134 } 135 136 @Override hashCode()137 public int hashCode() { 138 return Objects.hash(fieldElem, getterElem); 139 } 140 } 141 142 /** 143 * Returns the field (if it exists and is visible) and the getter for a property. If the field is 144 * not available, returns {@code null}. 145 */ getFieldAndGetterForProperty( Symbol.MethodSymbol symbol, String capPropName)146 private FieldAndGetterElements getFieldAndGetterForProperty( 147 Symbol.MethodSymbol symbol, String capPropName) { 148 Element field = null; 149 Element getter = null; 150 String fieldName = decapitalize(capPropName); 151 String getterName = "get" + capPropName; 152 for (Symbol elem : getEnclosedElements(symbol.owner)) { 153 if (elem.getKind().isField() && elem.getSimpleName().toString().equals(fieldName)) { 154 if (field != null) { 155 throw new RuntimeException("already found field " + fieldName); 156 } 157 field = elem; 158 } else if (elem.getKind().equals(ElementKind.METHOD) 159 && elem.getSimpleName().toString().equals(getterName)) { 160 if (getter != null) { 161 throw new RuntimeException("already found getter " + getterName); 162 } 163 getter = elem; 164 } 165 } 166 if (field != null && field.asType().getKind().isPrimitive()) { 167 // ignore primitive properties 168 return new FieldAndGetterElements(null, null); 169 } 170 return new FieldAndGetterElements(field, getter); 171 } 172 decapitalize(String str)173 private static String decapitalize(String str) { 174 // assumes str is non-null and non-empty 175 char c[] = str.toCharArray(); 176 c[0] = Character.toLowerCase(c[0]); 177 return new String(c); 178 } 179 thriftIsSetCall(Symbol.MethodSymbol symbol, Types types)180 private boolean thriftIsSetCall(Symbol.MethodSymbol symbol, Types types) { 181 // noinspection ConstantConditions 182 return tbaseType.isPresent() 183 && symbol.getSimpleName().toString().startsWith("isSet") 184 // weeds out the isSet() method in TBase itself 185 && symbol.getParameters().length() == 0 186 && types.isSubtype(symbol.owner.type, tbaseType.get()); 187 } 188 } 189