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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 
     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 = dyn_cast<TypedefType>(RetTy.getTypePtr())) {
     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 
     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 
     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 
     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