1 /*
2 * Copyright (C) 2019 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
17 #include <vector>
18
19 #include "AST.h"
20 #include "CompoundType.h"
21 #include "Lint.h"
22 #include "LintRegistry.h"
23 #include "Location.h"
24 #include "Type.h"
25
26 namespace android {
27
checkSmallStructs(const AST & ast,std::vector<Lint> * errors)28 static void checkSmallStructs(const AST& ast, std::vector<Lint>* errors) {
29 // Should lint if it contains a union type at any level
30 std::unordered_set<const Type*> visited;
31 ast.getRootScope().recursivePass(
32 Type::ParseStage::COMPLETED,
33 [&](const Type* type) -> status_t {
34 if (!type->isCompoundType()) return OK;
35
36 const CompoundType* compoundType = static_cast<const CompoundType*>(type);
37
38 // Will lint in the file that contains it
39 if (!Location::inSameFile(compoundType->location(),
40 ast.getRootScope().location())) {
41 return OK;
42 }
43
44 if (compoundType->getReferences().size() == 0) {
45 errors->push_back(
46 Lint(ERROR, compoundType->location())
47 << compoundType->typeName() << " contains no elements.\n"
48 << "Prefer using android.hidl.safe_union@1.0::Monostate instead.\n");
49 } else if (compoundType->getReferences().size() == 1) {
50 errors->push_back(Lint(ERROR, compoundType->location())
51 << compoundType->typeName() << " only contains 1 element.\n"
52 << "Prefer using the type directly since wrapping it adds "
53 << "memory and performance overhead.\n");
54 }
55
56 return OK;
57 },
58 &visited);
59 }
60
61 REGISTER_LINT(checkSmallStructs);
62
63 } // namespace android