1//===- CocoaConventions.h - Special handling of Cocoa conventions -*- C++ -*--//
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// This file implements cocoa naming convention analysis.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
14#include "clang/AST/Decl.h"
15#include "clang/AST/DeclObjC.h"
16#include "clang/AST/Type.h"
17#include "clang/Basic/CharInfo.h"
18#include "llvm/ADT/StringExtras.h"
19#include "llvm/Support/ErrorHandling.h"
20
21using namespace clang;
22using namespace ento;
23
24bool cocoa::isRefType(QualType RetTy, StringRef Prefix,
25 StringRef Name) {
26 // Recursively walk the typedef stack, allowing typedefs of reference types.
27 while (const TypedefType *TD = RetTy->getAs<TypedefType>()) {
28 StringRef TDName = TD->getDecl()->getIdentifier()->getName();
29 if (TDName.starts_with(Prefix) && TDName.ends_with(Suffix: "Ref"))
30 return true;
31 // XPC unfortunately uses CF-style function names, but aren't CF types.
32 if (TDName.starts_with(Prefix: "xpc_"))
33 return false;
34 RetTy = TD->getDecl()->getUnderlyingType();
35 }
36
37 if (Name.empty())
38 return false;
39
40 // Is the type void*?
41 const PointerType* PT = RetTy->castAs<PointerType>();
42 if (!PT || !PT->getPointeeType().getUnqualifiedType()->isVoidType())
43 return false;
44
45 // Does the name start with the prefix?
46 return Name.starts_with(Prefix);
47}
48
49/// Returns true when the passed-in type is a CF-style reference-counted
50/// type from the DiskArbitration framework.
51static bool isDiskArbitrationAPIRefType(QualType T) {
52 return cocoa::isRefType(RetTy: T, Prefix: "DADisk") ||
53 cocoa::isRefType(RetTy: T, Prefix: "DADissenter") ||
54 cocoa::isRefType(RetTy: T, Prefix: "DASessionRef");
55}
56
57bool coreFoundation::isCFObjectRef(QualType T) {
58 return cocoa::isRefType(RetTy: T, Prefix: "CF") || // Core Foundation.
59 cocoa::isRefType(RetTy: T, Prefix: "CG") || // Core Graphics.
60 cocoa::isRefType(RetTy: T, Prefix: "CM") || // Core Media.
61 isDiskArbitrationAPIRefType(T);
62}
63
64
65bool cocoa::isCocoaObjectRef(QualType Ty) {
66 if (!Ty->isObjCObjectPointerType())
67 return false;
68
69 const ObjCObjectPointerType *PT = Ty->getAs<ObjCObjectPointerType>();
70
71 // Can be true for objects with the 'NSObject' attribute.
72 if (!PT)
73 return true;
74
75 // We assume that id<..>, id, Class, and Class<..> all represent tracked
76 // objects.
77 if (PT->isObjCIdType() || PT->isObjCQualifiedIdType() ||
78 PT->isObjCClassType() || PT->isObjCQualifiedClassType())
79 return true;
80
81 // Does the interface subclass NSObject?
82 // FIXME: We can memoize here if this gets too expensive.
83 const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
84
85 // Assume that anything declared with a forward declaration and no
86 // @interface subclasses NSObject.
87 if (!ID->hasDefinition())
88 return true;
89
90 for ( ; ID ; ID = ID->getSuperClass())
91 if (ID->getIdentifier()->getName() == "NSObject")
92 return true;
93
94 return false;
95}
96
97bool coreFoundation::followsCreateRule(const FunctionDecl *fn) {
98 // For now, *just* base this on the function name, not on anything else.
99
100 const IdentifierInfo *ident = fn->getIdentifier();
101 if (!ident) return false;
102 StringRef functionName = ident->getName();
103
104 StringRef::iterator it = functionName.begin();
105 StringRef::iterator start = it;
106 StringRef::iterator endI = functionName.end();
107
108 while (true) {
109 // Scan for the start of 'create' or 'copy'.
110 for ( ; it != endI ; ++it) {
111 // Search for the first character. It can either be 'C' or 'c'.
112 char ch = *it;
113 if (ch == 'C' || ch == 'c') {
114 // Make sure this isn't something like 'recreate' or 'Scopy'.
115 if (ch == 'c' && it != start && isLetter(c: *(it - 1)))
116 continue;
117
118 ++it;
119 break;
120 }
121 }
122
123 // Did we hit the end of the string? If so, we didn't find a match.
124 if (it == endI)
125 return false;
126
127 // Scan for *lowercase* 'reate' or 'opy', followed by no lowercase
128 // character.
129 StringRef suffix = functionName.substr(Start: it - start);
130 if (suffix.starts_with(Prefix: "reate")) {
131 it += 5;
132 } else if (suffix.starts_with(Prefix: "opy")) {
133 it += 3;
134 } else {
135 // Keep scanning.
136 continue;
137 }
138
139 if (it == endI || !isLowercase(c: *it))
140 return true;
141
142 // If we matched a lowercase character, it isn't the end of the
143 // word. Keep scanning.
144 }
145}
146