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.startswith(Prefix) && TDName.endswith("Ref"))
30      return true;
31    // XPC unfortunately uses CF-style function names, but aren't CF types.
32    if (TDName.startswith("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.startswith(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(T, "DADisk") ||
53      cocoa::isRefType(T, "DADissenter") ||
54      cocoa::isRefType(T, "DASessionRef");
55}
56
57bool coreFoundation::isCFObjectRef(QualType T) {
58  return cocoa::isRefType(T, "CF") || // Core Foundation.
59         cocoa::isRefType(T, "CG") || // Core Graphics.
60         cocoa::isRefType(T, "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(*(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(it - start);
130    if (suffix.startswith("reate")) {
131      it += 5;
132    }
133    else if (suffix.startswith("opy")) {
134      it += 3;
135    } else {
136      // Keep scanning.
137      continue;
138    }
139
140    if (it == endI || !isLowercase(*it))
141      return true;
142
143    // If we matched a lowercase character, it isn't the end of the
144    // word.  Keep scanning.
145  }
146}
147