CocoaConventions.cpp revision 5078d46af381b27be1c7e3c3e0c517e4cf7cc064
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 defines
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
15#include "clang/AST/Type.h"
16#include "clang/AST/Decl.h"
17#include "clang/AST/DeclObjC.h"
18#include "llvm/ADT/StringExtras.h"
19
20using namespace clang;
21using namespace ento;
22
23using llvm::StringRef;
24
25// The "fundamental rule" for naming conventions of methods:
26//  (url broken into two lines)
27//  http://developer.apple.com/documentation/Cocoa/Conceptual/
28//     MemoryMgmt/Tasks/MemoryManagementRules.html
29//
30// "You take ownership of an object if you create it using a method whose name
31//  begins with "alloc" or "new" or contains "copy" (for example, alloc,
32//  newObject, or mutableCopy), or if you send it a retain message. You are
33//  responsible for relinquishing ownership of objects you own using release
34//  or autorelease. Any other time you receive an object, you must
35//  not release it."
36//
37
38static bool isWordEnd(char ch, char prev, char next) {
39  return ch == '\0'
40      || (islower(prev) && isupper(ch)) // xxxC
41      || (isupper(prev) && isupper(ch) && islower(next)) // XXCreate
42      || !isalpha(ch);
43}
44
45static const char* parseWord(const char* s) {
46  char ch = *s, prev = '\0';
47  assert(ch != '\0');
48  char next = *(s+1);
49  while (!isWordEnd(ch, prev, next)) {
50    prev = ch;
51    ch = next;
52    next = *((++s)+1);
53  }
54  return s;
55}
56
57cocoa::NamingConvention cocoa::deriveNamingConvention(Selector S,
58                                                      bool ignorePrefix) {
59  IdentifierInfo *II = S.getIdentifierInfoForSlot(0);
60
61  if (!II)
62    return NoConvention;
63
64  const char *s = II->getNameStart();
65
66  const char *orig = s;
67  // A method/function name may contain a prefix.  We don't know it is there,
68  // however, until we encounter the first '_'.
69  while (*s != '\0') {
70    // Skip '_', numbers, ':', etc.
71    if (*s == '_' || !isalpha(*s)) {
72      ++s;
73      continue;
74    }
75    break;
76  }
77
78  if (!ignorePrefix && s != orig)
79    return NoConvention;
80
81  // Parse the first word, and look for specific keywords.
82  const char *wordEnd = parseWord(s);
83  assert(wordEnd > s);
84  unsigned len = wordEnd - s;
85
86  switch (len) {
87    default:
88      return NoConvention;
89    case 3:
90      // Methods starting with 'new' follow the create rule.
91      return (memcmp(s, "new", 3) == 0) ? CreateRule : NoConvention;
92    case 4:
93      // Methods starting with 'copy' follow the create rule.
94      if (memcmp(s, "copy", 4) == 0)
95        return CreateRule;
96      // Methods starting with 'init' follow the init rule.
97      if (memcmp(s, "init", 4) == 0)
98        return InitRule;
99      return NoConvention;
100    case 5:
101      return (memcmp(s, "alloc", 5) == 0) ? CreateRule : NoConvention;
102    case 7:
103      // Methods starting with 'mutableCopy' follow the create rule.
104      if (memcmp(s, "mutable", 7) == 0) {
105        // Look at the next word to see if it is "Copy".
106        s = wordEnd;
107        if (*s != '\0') {
108          wordEnd = parseWord(s);
109          len = wordEnd - s;
110          if (len == 4 && memcmp(s, "Copy", 4) == 0)
111            return CreateRule;
112        }
113      }
114      return NoConvention;
115  }
116}
117
118bool cocoa::isRefType(QualType RetTy, llvm::StringRef Prefix,
119                      llvm::StringRef Name) {
120  // Recursively walk the typedef stack, allowing typedefs of reference types.
121  while (TypedefType* TD = dyn_cast<TypedefType>(RetTy.getTypePtr())) {
122    llvm::StringRef TDName = TD->getDecl()->getIdentifier()->getName();
123    if (TDName.startswith(Prefix) && TDName.endswith("Ref"))
124      return true;
125
126    RetTy = TD->getDecl()->getUnderlyingType();
127  }
128
129  if (Name.empty())
130    return false;
131
132  // Is the type void*?
133  const PointerType* PT = RetTy->getAs<PointerType>();
134  if (!(PT->getPointeeType().getUnqualifiedType()->isVoidType()))
135    return false;
136
137  // Does the name start with the prefix?
138  return Name.startswith(Prefix);
139}
140
141bool cocoa::isCFObjectRef(QualType T) {
142  return isRefType(T, "CF") || // Core Foundation.
143         isRefType(T, "CG") || // Core Graphics.
144         isRefType(T, "DADisk") || // Disk Arbitration API.
145         isRefType(T, "DADissenter") ||
146         isRefType(T, "DASessionRef");
147}
148
149
150bool cocoa::isCocoaObjectRef(QualType Ty) {
151  if (!Ty->isObjCObjectPointerType())
152    return false;
153
154  const ObjCObjectPointerType *PT = Ty->getAs<ObjCObjectPointerType>();
155
156  // Can be true for objects with the 'NSObject' attribute.
157  if (!PT)
158    return true;
159
160  // We assume that id<..>, id, Class, and Class<..> all represent tracked
161  // objects.
162  if (PT->isObjCIdType() || PT->isObjCQualifiedIdType() ||
163      PT->isObjCClassType() || PT->isObjCQualifiedClassType())
164    return true;
165
166  // Does the interface subclass NSObject?
167  // FIXME: We can memoize here if this gets too expensive.
168  const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
169
170  // Assume that anything declared with a forward declaration and no
171  // @interface subclasses NSObject.
172  if (ID->isForwardDecl())
173    return true;
174
175  for ( ; ID ; ID = ID->getSuperClass())
176    if (ID->getIdentifier()->getName() == "NSObject")
177      return true;
178
179  return false;
180}
181