base/apple/foundation_util.h

// Copyright 2008 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MINI_CHROMIUM_BASE_APPLE_FOUNDATION_UTIL_H_
#define MINI_CHROMIUM_BASE_APPLE_FOUNDATION_UTIL_H_

#include "base/logging.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_IOS)
#include <CoreText/CoreText.h>
#else
#include <ApplicationServices/ApplicationServices.h>
#endif

#if defined(__OBJC__)
#import <Foundation/Foundation.h>
#else  // defined(__OBJC__)
#include <CoreFoundation/CoreFoundation.h>
#endif  // defined(__OBJC__)

namespace base {
namespace apple {

// CFCast<>() and CFCastStrict<>() cast a basic CFTypeRef to a more
// specific CoreFoundation type. The compatibility of the passed
// object is found by comparing its opaque type against the
// requested type identifier. If the supplied object is not
// compatible with the requested return type, CFCast<>() returns
// NULL and CFCastStrict<>() will DCHECK. Providing a NULL pointer
// to either variant results in NULL being returned without
// triggering any DCHECK.
//
// Example usage:
// CFNumberRef some_number = base::apple::CFCast<CFNumberRef>(
//     CFArrayGetValueAtIndex(array, index));
//
// CFTypeRef hello = CFSTR("hello world");
// CFStringRef some_string = base::apple::CFCastStrict<CFStringRef>(hello);

template <typename T>
T CFCast(const CFTypeRef& cf_val);

template <typename T>
T CFCastStrict(const CFTypeRef& cf_val);

#define CF_CAST_DECL(TypeCF)                                \
  template <>                                               \
  TypeCF##Ref CFCast<TypeCF##Ref>(const CFTypeRef& cf_val); \
                                                            \
  template <>                                               \
  TypeCF##Ref CFCastStrict<TypeCF##Ref>(const CFTypeRef& cf_val)

CF_CAST_DECL(CFArray);
CF_CAST_DECL(CFBag);
CF_CAST_DECL(CFBoolean);
CF_CAST_DECL(CFData);
CF_CAST_DECL(CFDate);
CF_CAST_DECL(CFDictionary);
CF_CAST_DECL(CFNull);
CF_CAST_DECL(CFNumber);
CF_CAST_DECL(CFSet);
CF_CAST_DECL(CFString);
CF_CAST_DECL(CFURL);
CF_CAST_DECL(CFUUID);

CF_CAST_DECL(CGColor);

CF_CAST_DECL(CTFont);
CF_CAST_DECL(CTRun);

#undef CF_CAST_DECL

#if defined(__OBJC__)

// ObjCCast<>() and ObjCCastStrict<>() cast a basic id to a more
// specific (NSObject-derived) type. The compatibility of the passed
// object is found by checking if it's a kind of the requested type
// identifier. If the supplied object is not compatible with the
// requested return type, ObjCCast<>() returns nil and
// ObjCCastStrict<>() will DCHECK. Providing a nil pointer to either
// variant results in nil being returned without triggering any DCHECK.
//
// The strict variant is useful when retrieving a value from a
// collection which only has values of a specific type, e.g. an
// NSArray of NSStrings. The non-strict variant is useful when
// retrieving values from data that you can't fully control. For
// example, a plist read from disk may be beyond your exclusive
// control, so you'd only want to check that the values you retrieve
// from it are of the expected types, but not crash if they're not.
//
// Example usage:
// NSString* version = base::apple::ObjCCast<NSString>(
//     [bundle objectForInfoDictionaryKey:@"CFBundleShortVersionString"]);
//
// NSString* str = base::apple::ObjCCastStrict<NSString>(
//     [ns_arr_of_ns_strs objectAtIndex:0]);
template <typename T>
T* ObjCCast(id objc_val) {
  if ([objc_val isKindOfClass:[T class]]) {
    return reinterpret_cast<T*>(objc_val);
  }
  return nil;
}

template <typename T>
T* ObjCCastStrict(id objc_val) {
  T* rv = ObjCCast<T>(objc_val);
  DCHECK(objc_val == nil || rv);
  return rv;
}

#endif  // defined(__OBJC__)

}  // namespace apple
}  // namespace base

#endif  // MINI_CHROMIUM_BASE_APPLE_FOUNDATION_UTIL_H_