iOS/Pods/GoogleUtilities/GoogleUtilities/Reachability/GULReachabilityChecker.m

   1 // Copyright 2017 Google
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //      http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 #import <Foundation/Foundation.h>
  16
  17 #import "GULReachabilityChecker+Internal.h"
  18 #import "Private/GULReachabilityChecker.h"
  19 #import "Private/GULReachabilityMessageCode.h"
  20
  21 #import <GoogleUtilities/GULLogger.h>
  22 #import <GoogleUtilities/GULReachabilityChecker.h>
  23
  24 static GULLoggerService kGULLoggerReachability = @"[GULReachability]";
  25
  26 static void ReachabilityCallback(SCNetworkReachabilityRef reachability,
  27                                  SCNetworkReachabilityFlags flags,
  28                                  void *info);
  29
  30 static const struct GULReachabilityApi kGULDefaultReachabilityApi = {
  31     SCNetworkReachabilityCreateWithName,
  32     SCNetworkReachabilitySetCallback,
  33     SCNetworkReachabilityScheduleWithRunLoop,
  34     SCNetworkReachabilityUnscheduleFromRunLoop,
  35     CFRelease,
  36 };
  37
  38 static NSString *const kGULReachabilityUnknownStatus = @"Unknown";
  39 static NSString *const kGULReachabilityConnectedStatus = @"Connected";
  40 static NSString *const kGULReachabilityDisconnectedStatus = @"Disconnected";
  41
  42 @interface GULReachabilityChecker ()
  43
  44 @property(nonatomic, assign) const struct GULReachabilityApi *reachabilityApi;
  45 @property(nonatomic, assign) GULReachabilityStatus reachabilityStatus;
  46 @property(nonatomic, copy) NSString *host;
  47 @property(nonatomic, assign) SCNetworkReachabilityRef reachability;
  48
  49 @end
  50
  51 @implementation GULReachabilityChecker
  52
  53 @synthesize reachabilityApi = reachabilityApi_;
  54 @synthesize reachability = reachability_;
  55
  56 - (const struct GULReachabilityApi *)reachabilityApi {
  57   return reachabilityApi_;
  58 }
  59
  60 - (void)setReachabilityApi:(const struct GULReachabilityApi *)reachabilityApi {
  61   if (reachability_) {
  62     GULLogError(kGULLoggerReachability, NO,
  63                 [NSString stringWithFormat:@"I-REA%06ld", (long)kGULReachabilityMessageCode000],
  64                 @"Cannot change reachability API while reachability is running. "
  65                 @"Call stop first.");
  66     return;
  67   }
  68   reachabilityApi_ = reachabilityApi;
  69 }
  70
  71 @synthesize reachabilityStatus = reachabilityStatus_;
  72 @synthesize host = host_;
  73 @synthesize reachabilityDelegate = reachabilityDelegate_;
  74
  75 - (BOOL)isActive {
  76   return reachability_ != nil;
  77 }
  78
  79 - (void)setReachabilityDelegate:(id<GULReachabilityDelegate>)reachabilityDelegate {
  80   if (reachabilityDelegate &&
  81       (![(NSObject *)reachabilityDelegate conformsToProtocol:@protocol(GULReachabilityDelegate)])) {
  82     GULLogError(kGULLoggerReachability, NO,
  83                 [NSString stringWithFormat:@"I-NET%06ld", (long)kGULReachabilityMessageCode005],
  84                 @"Reachability delegate doesn't conform to Reachability protocol.");
  85     return;
  86   }
  87   reachabilityDelegate_ = reachabilityDelegate;
  88 }
  89
  90 - (instancetype)initWithReachabilityDelegate:(id<GULReachabilityDelegate>)reachabilityDelegate
  91                                     withHost:(NSString *)host {
  92   self = [super init];
  93
  94   if (!host || !host.length) {
  95     GULLogError(kGULLoggerReachability, NO,
  96                 [NSString stringWithFormat:@"I-REA%06ld", (long)kGULReachabilityMessageCode001],
  97                 @"Invalid host specified");
  98     return nil;
  99   }
 100   if (self) {
 101     [self setReachabilityDelegate:reachabilityDelegate];
 102     reachabilityApi_ = &kGULDefaultReachabilityApi;
 103     reachabilityStatus_ = kGULReachabilityUnknown;
 104     host_ = [host copy];
 105     reachability_ = nil;
 106   }
 107   return self;
 108 }
 109
 110 - (void)dealloc {
 111   reachabilityDelegate_ = nil;
 112   [self stop];
 113 }
 114
 115 - (BOOL)start {
 116   if (!reachability_) {
 117     reachability_ = reachabilityApi_->createWithNameFn(kCFAllocatorDefault, [host_ UTF8String]);
 118     if (!reachability_) {
 119       return NO;
 120     }
 121     SCNetworkReachabilityContext context = {
 122         0,                       /* version */
 123         (__bridge void *)(self), /* info (passed as last parameter to reachability callback) */
 124         NULL,                    /* retain */
 125         NULL,                    /* release */
 126         NULL                     /* copyDescription */
 127     };
 128     if (!reachabilityApi_->setCallbackFn(reachability_, ReachabilityCallback, &context) ||
 129         !reachabilityApi_->scheduleWithRunLoopFn(reachability_, CFRunLoopGetMain(),
 130                                                  kCFRunLoopCommonModes)) {
 131       reachabilityApi_->releaseFn(reachability_);
 132       reachability_ = nil;
 133
 134       GULLogError(kGULLoggerReachability, NO,
 135                   [NSString stringWithFormat:@"I-REA%06ld", (long)kGULReachabilityMessageCode002],
 136                   @"Failed to start reachability handle");
 137       return NO;
 138     }
 139   }
 140   GULLogDebug(kGULLoggerReachability, NO,
 141               [NSString stringWithFormat:@"I-REA%06ld", (long)kGULReachabilityMessageCode003],
 142               @"Monitoring the network status");
 143   return YES;
 144 }
 145
 146 - (void)stop {
 147   if (reachability_) {
 148     reachabilityStatus_ = kGULReachabilityUnknown;
 149     reachabilityApi_->unscheduleFromRunLoopFn(reachability_, CFRunLoopGetMain(),
 150                                               kCFRunLoopCommonModes);
 151     reachabilityApi_->releaseFn(reachability_);
 152     reachability_ = nil;
 153   }
 154 }
 155
 156 - (GULReachabilityStatus)statusForFlags:(SCNetworkReachabilityFlags)flags {
 157   GULReachabilityStatus status = kGULReachabilityNotReachable;
 158   // If the Reachable flag is not set, we definitely don't have connectivity.
 159   if (flags & kSCNetworkReachabilityFlagsReachable) {
 160     // Reachable flag is set. Check further flags.
 161     if (!(flags & kSCNetworkReachabilityFlagsConnectionRequired)) {
 162 // Connection required flag is not set, so we have connectivity.
 163 #if TARGET_OS_IOS || TARGET_OS_TV
 164       status = (flags & kSCNetworkReachabilityFlagsIsWWAN) ? kGULReachabilityViaCellular
 165                                                            : kGULReachabilityViaWifi;
 166 #elif TARGET_OS_OSX
 167       status = kGULReachabilityViaWifi;
 168 #endif
 169     } else if ((flags & (kSCNetworkReachabilityFlagsConnectionOnDemand |
 170                          kSCNetworkReachabilityFlagsConnectionOnTraffic)) &&
 171                !(flags & kSCNetworkReachabilityFlagsInterventionRequired)) {
 172 // If the connection on demand or connection on traffic flag is set, and user intervention
 173 // is not required, we have connectivity.
 174 #if TARGET_OS_IOS || TARGET_OS_TV
 175       status = (flags & kSCNetworkReachabilityFlagsIsWWAN) ? kGULReachabilityViaCellular
 176                                                            : kGULReachabilityViaWifi;
 177 #elif TARGET_OS_OSX
 178       status = kGULReachabilityViaWifi;
 179 #endif
 180     }
 181   }
 182   return status;
 183 }
 184
 185 - (void)reachabilityFlagsChanged:(SCNetworkReachabilityFlags)flags {
 186   GULReachabilityStatus status = [self statusForFlags:flags];
 187   if (reachabilityStatus_ != status) {
 188     NSString *reachabilityStatusString;
 189     if (status == kGULReachabilityUnknown) {
 190       reachabilityStatusString = kGULReachabilityUnknownStatus;
 191     } else {
 192       reachabilityStatusString = (status == kGULReachabilityNotReachable)
 193                                      ? kGULReachabilityDisconnectedStatus
 194                                      : kGULReachabilityConnectedStatus;
 195     }
 196
 197     GULLogDebug(kGULLoggerReachability, NO,
 198                 [NSString stringWithFormat:@"I-REA%06ld", (long)kGULReachabilityMessageCode004],
 199                 @"Network status has changed. Code:%@, status:%@", @(status),
 200                 reachabilityStatusString);
 201     reachabilityStatus_ = status;
 202     [reachabilityDelegate_ reachability:self statusChanged:reachabilityStatus_];
 203   }
 204 }
 205
 206 @end
 207
 208 static void ReachabilityCallback(SCNetworkReachabilityRef reachability,
 209                                  SCNetworkReachabilityFlags flags,
 210                                  void *info) {
 211   GULReachabilityChecker *checker = (__bridge GULReachabilityChecker *)info;
 212   [checker reachabilityFlagsChanged:flags];
 213 }
 214
 215 // This function used to be at the top of the file, but it was moved here
 216 // as a workaround for a suspected compiler bug. When compiled in Release mode
 217 // and run on an iOS device with WiFi disabled, the reachability code crashed
 218 // when calling SCNetworkReachabilityScheduleWithRunLoop, or shortly thereafter.
 219 // After unsuccessfully trying to diagnose the cause of the crash, it was
 220 // discovered that moving this function to the end of the file magically fixed
 221 // the crash. If you are going to edit this file, exercise caution and make sure
 222 // to test thoroughly with an iOS device under various network conditions.
 223 const NSString *GULReachabilityStatusString(GULReachabilityStatus status) {
 224   switch (status) {
 225     case kGULReachabilityUnknown:
 226       return @"Reachability Unknown";
 227
 228     case kGULReachabilityNotReachable:
 229       return @"Not reachable";
 230
 231     case kGULReachabilityViaWifi:
 232       return @"Reachable via Wifi";
 233
 234     case kGULReachabilityViaCellular:
 235       return @"Reachable via Cellular Data";
 236
 237     default:
 238       return [NSString stringWithFormat:@"Invalid reachability status %d", (int)status];
 239   }
 240 }