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1 //===- CocoaConventions.h - Special handling of Cocoa conventions -*- C++ -*--//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements cocoa naming convention analysis.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/DeclObjC.h"
17 #include "clang/AST/Type.h"
18 #include "clang/Basic/CharInfo.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/Support/ErrorHandling.h"
21 
22 using namespace clang;
23 using namespace ento;
24 
isRefType(QualType RetTy,StringRef Prefix,StringRef Name)25 bool cocoa::isRefType(QualType RetTy, StringRef Prefix,
26                       StringRef Name) {
27   // Recursively walk the typedef stack, allowing typedefs of reference types.
28   while (const TypedefType *TD = RetTy->getAs<TypedefType>()) {
29     StringRef TDName = TD->getDecl()->getIdentifier()->getName();
30     if (TDName.startswith(Prefix) && TDName.endswith("Ref"))
31       return true;
32     // XPC unfortunately uses CF-style function names, but aren't CF types.
33     if (TDName.startswith("xpc_"))
34       return false;
35     RetTy = TD->getDecl()->getUnderlyingType();
36   }
37 
38   if (Name.empty())
39     return false;
40 
41   // Is the type void*?
42   const PointerType* PT = RetTy->getAs<PointerType>();
43   if (!(PT->getPointeeType().getUnqualifiedType()->isVoidType()))
44     return false;
45 
46   // Does the name start with the prefix?
47   return Name.startswith(Prefix);
48 }
49 
isCFObjectRef(QualType T)50 bool coreFoundation::isCFObjectRef(QualType T) {
51   return cocoa::isRefType(T, "CF") || // Core Foundation.
52          cocoa::isRefType(T, "CG") || // Core Graphics.
53          cocoa::isRefType(T, "DADisk") || // Disk Arbitration API.
54          cocoa::isRefType(T, "DADissenter") ||
55          cocoa::isRefType(T, "DASessionRef");
56 }
57 
58 
isCocoaObjectRef(QualType Ty)59 bool cocoa::isCocoaObjectRef(QualType Ty) {
60   if (!Ty->isObjCObjectPointerType())
61     return false;
62 
63   const ObjCObjectPointerType *PT = Ty->getAs<ObjCObjectPointerType>();
64 
65   // Can be true for objects with the 'NSObject' attribute.
66   if (!PT)
67     return true;
68 
69   // We assume that id<..>, id, Class, and Class<..> all represent tracked
70   // objects.
71   if (PT->isObjCIdType() || PT->isObjCQualifiedIdType() ||
72       PT->isObjCClassType() || PT->isObjCQualifiedClassType())
73     return true;
74 
75   // Does the interface subclass NSObject?
76   // FIXME: We can memoize here if this gets too expensive.
77   const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
78 
79   // Assume that anything declared with a forward declaration and no
80   // @interface subclasses NSObject.
81   if (!ID->hasDefinition())
82     return true;
83 
84   for ( ; ID ; ID = ID->getSuperClass())
85     if (ID->getIdentifier()->getName() == "NSObject")
86       return true;
87 
88   return false;
89 }
90 
followsCreateRule(const FunctionDecl * fn)91 bool coreFoundation::followsCreateRule(const FunctionDecl *fn) {
92   // For now, *just* base this on the function name, not on anything else.
93 
94   const IdentifierInfo *ident = fn->getIdentifier();
95   if (!ident) return false;
96   StringRef functionName = ident->getName();
97 
98   StringRef::iterator it = functionName.begin();
99   StringRef::iterator start = it;
100   StringRef::iterator endI = functionName.end();
101 
102   while (true) {
103     // Scan for the start of 'create' or 'copy'.
104     for ( ; it != endI ; ++it) {
105       // Search for the first character.  It can either be 'C' or 'c'.
106       char ch = *it;
107       if (ch == 'C' || ch == 'c') {
108         // Make sure this isn't something like 'recreate' or 'Scopy'.
109         if (ch == 'c' && it != start && isLetter(*(it - 1)))
110           continue;
111 
112         ++it;
113         break;
114       }
115     }
116 
117     // Did we hit the end of the string?  If so, we didn't find a match.
118     if (it == endI)
119       return false;
120 
121     // Scan for *lowercase* 'reate' or 'opy', followed by no lowercase
122     // character.
123     StringRef suffix = functionName.substr(it - start);
124     if (suffix.startswith("reate")) {
125       it += 5;
126     }
127     else if (suffix.startswith("opy")) {
128       it += 3;
129     } else {
130       // Keep scanning.
131       continue;
132     }
133 
134     if (it == endI || !isLowercase(*it))
135       return true;
136 
137     // If we matched a lowercase character, it isn't the end of the
138     // word.  Keep scanning.
139   }
140 }
141