1 //===--- FunctionNamingCheck.cpp - clang-tidy -----------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "FunctionNamingCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "llvm/Support/Regex.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang {
17 namespace tidy {
18 namespace google {
19 namespace objc {
20
21 namespace {
22
validFunctionNameRegex(bool RequirePrefix)23 std::string validFunctionNameRegex(bool RequirePrefix) {
24 // Allow the following name patterns for all functions:
25 // • ABFoo (prefix + UpperCamelCase)
26 // • ABURL (prefix + capitalized acronym/initialism)
27 //
28 // If no prefix is required, additionally allow the following name patterns:
29 // • Foo (UpperCamelCase)
30 // • URL (capitalized acronym/initialism)
31 //
32 // The function name following the prefix can contain standard and
33 // non-standard capitalized character sequences including acronyms,
34 // initialisms, and prefixes of symbols (e.g., UIColorFromNSString). For this
35 // reason, the regex only verifies that the function name after the prefix
36 // begins with a capital letter followed by an arbitrary sequence of
37 // alphanumeric characters.
38 //
39 // If a prefix is required, the regex checks for a capital letter followed by
40 // another capital letter or number that is part of the prefix and another
41 // capital letter or number that begins the name following the prefix.
42 std::string FunctionNameMatcher =
43 std::string(RequirePrefix ? "[A-Z][A-Z0-9]+" : "") + "[A-Z][a-zA-Z0-9]*";
44 return std::string("::(") + FunctionNameMatcher + ")$";
45 }
46
47 /// For now we will only fix functions of static storage class with names like
48 /// 'functionName' or 'function_name' and convert them to 'FunctionName'. For
49 /// other cases the user must determine an appropriate name on their own.
generateFixItHint(const FunctionDecl * Decl)50 FixItHint generateFixItHint(const FunctionDecl *Decl) {
51 // A fixit can be generated for functions of static storage class but
52 // otherwise the check cannot determine the appropriate function name prefix
53 // to use.
54 if (Decl->getStorageClass() != SC_Static)
55 return FixItHint();
56
57 StringRef Name = Decl->getName();
58 std::string NewName = Decl->getName().str();
59
60 size_t Index = 0;
61 bool AtWordBoundary = true;
62 while (Index < NewName.size()) {
63 char Ch = NewName[Index];
64 if (isalnum(Ch)) {
65 // Capitalize the first letter after every word boundary.
66 if (AtWordBoundary) {
67 NewName[Index] = toupper(NewName[Index]);
68 AtWordBoundary = false;
69 }
70
71 // Advance the index after every alphanumeric character.
72 Index++;
73 } else {
74 // Strip out any characters other than alphanumeric characters.
75 NewName.erase(Index, 1);
76 AtWordBoundary = true;
77 }
78 }
79
80 // Generate a fixit hint if the new name is different.
81 if (NewName != Name)
82 return FixItHint::CreateReplacement(
83 CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
84 llvm::StringRef(NewName));
85
86 return FixItHint();
87 }
88
89 } // namespace
90
registerMatchers(MatchFinder * Finder)91 void FunctionNamingCheck::registerMatchers(MatchFinder *Finder) {
92 // Enforce Objective-C function naming conventions on all functions except:
93 // • Functions defined in system headers.
94 // • C++ member functions.
95 // • Namespaced functions.
96 // • Implicitly defined functions.
97 // • The main function.
98 Finder->addMatcher(
99 functionDecl(
100 unless(anyOf(isExpansionInSystemHeader(), cxxMethodDecl(),
101 hasAncestor(namespaceDecl()), isMain(), isImplicit(),
102 matchesName(validFunctionNameRegex(true)),
103 allOf(isStaticStorageClass(),
104 matchesName(validFunctionNameRegex(false))))))
105 .bind("function"),
106 this);
107 }
108
check(const MatchFinder::MatchResult & Result)109 void FunctionNamingCheck::check(const MatchFinder::MatchResult &Result) {
110 const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("function");
111
112 bool IsGlobal = MatchedDecl->getStorageClass() != SC_Static;
113 diag(MatchedDecl->getLocation(),
114 "%select{static function|function in global namespace}1 named %0 must "
115 "%select{be in|have an appropriate prefix followed by}1 Pascal case as "
116 "required by Google Objective-C style guide")
117 << MatchedDecl << IsGlobal << generateFixItHint(MatchedDecl);
118 }
119
120 } // namespace objc
121 } // namespace google
122 } // namespace tidy
123 } // namespace clang
124