//===- CocoaConventions.h - Special handling of Cocoa conventions -*- C++ -*--//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file implements cocoa naming convention analysis.

//

//===----------------------------------------------------------------------===//

#include "clang/Analysis/DomainSpecific/CocoaConventions.h"

#include "clang/AST/Decl.h"

#include "clang/AST/DeclObjC.h"

#include "clang/AST/Type.h"

#include "clang/Basic/CharInfo.h"

#include "llvm/ADT/StringExtras.h"

#include "llvm/Support/ErrorHandling.h"

using namespace clang;

using namespace ento;

bool cocoa::isRefType(QualType RetTy, StringRef Prefix,

                      StringRef Name) {

  // Recursively walk the typedef stack, allowing typedefs of reference types.

  while (const TypedefType *TD = RetTy->getAs<TypedefType>()) {

    StringRef TDName = TD->getDecl()->getIdentifier()->getName();

    if (TDName.starts_with(Prefix) && TDName.ends_with("Ref"))

      return true;

    // XPC unfortunately uses CF-style function names, but aren't CF types.

    if (TDName.starts_with("xpc_"))

      return false;

    RetTy = TD->getDecl()->getUnderlyingType();

  }

  if (Name.empty())

    return false;

  // Is the type void*?

  const PointerType* PT = RetTy->castAs<PointerType>();

  if (!PT || !PT->getPointeeType().getUnqualifiedType()->isVoidType())

    return false;

  // Does the name start with the prefix?

  return Name.starts_with(Prefix);

}

/// Returns true when the passed-in type is a CF-style reference-counted

/// type from the DiskArbitration framework.

static bool isDiskArbitrationAPIRefType(QualType T) {

  return cocoa::isRefType(T, "DADisk") ||

      cocoa::isRefType(T, "DADissenter") ||

      cocoa::isRefType(T, "DASessionRef");

}

bool coreFoundation::isCFObjectRef(QualType T) {

  return cocoa::isRefType(T, "CF") || // Core Foundation.

         cocoa::isRefType(T, "CG") || // Core Graphics.

         cocoa::isRefType(T, "CM") || // Core Media.

         isDiskArbitrationAPIRefType(T);

}

bool cocoa::isCocoaObjectRef(QualType Ty) {

  if (!Ty->isObjCObjectPointerType())

    return false;

  const ObjCObjectPointerType *PT = Ty->getAs<ObjCObjectPointerType>();

  // Can be true for objects with the 'NSObject' attribute.

  if (!PT)

    return true;

  // We assume that id<..>, id, Class, and Class<..> all represent tracked

  // objects.

  if (PT->isObjCIdType() || PT->isObjCQualifiedIdType() ||

      PT->isObjCClassType() || PT->isObjCQualifiedClassType())

    return true;

  // Does the interface subclass NSObject?

  // FIXME: We can memoize here if this gets too expensive.

  const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();

  // Assume that anything declared with a forward declaration and no

  // @interface subclasses NSObject.

  if (!ID->hasDefinition())

    return true;

  for ( ; ID ; ID = ID->getSuperClass())

    if (ID->getIdentifier()->getName() == "NSObject")

      return true;

  return false;

}

bool coreFoundation::followsCreateRule(const FunctionDecl *fn) {

  // For now, *just* base this on the function name, not on anything else.

  const IdentifierInfo *ident = fn->getIdentifier();

  if (!ident) return false;

  StringRef functionName = ident->getName();

  StringRef::iterator it = functionName.begin();

  StringRef::iterator start = it;

  StringRef::iterator endI = functionName.end();

  while (true) {

    // Scan for the start of 'create' or 'copy'.

    for ( ; it != endI ; ++it) {

      // Search for the first character.  It can either be 'C' or 'c'.

      char ch = *it;

      if (ch == 'C' || ch == 'c') {

        // Make sure this isn't something like 'recreate' or 'Scopy'.

        if (ch == 'c' && it != start && isLetter(*(it - 1)))

          continue;

        ++it;

        break;

      }

    }

    // Did we hit the end of the string?  If so, we didn't find a match.

    if (it == endI)

      return false;

    // Scan for *lowercase* 'reate' or 'opy', followed by no lowercase

    // character.

    StringRef suffix = functionName.substr(it - start);

    if (suffix.starts_with("reate")) {

      it += 5;

    } else if (suffix.starts_with("opy")) {

      it += 3;

    } else {

      // Keep scanning.

      continue;

    }

    if (it == endI || !isLowercase(*it))

      return true;

    // If we matched a lowercase character, it isn't the end of the

    // word.  Keep scanning.

  }

}