Removing FSEvents code from FBCrashLogNotifier

Summary:
## Context
As mentioned [here](https://fb.workplace.com/groups/1042353022615812/permalink/2767866986731065/) by RE prod eng, they freqently kill fseventsd when it starts using too many resources. They don't currently do anything to ensure that it restarts correctly, and it doesn't appear as though they have it in their priorities.

What this means for us, is CrashLog collection is extremely unreliable (seems like ~30% of the time FSEvents is down), which means we can't observe the diagnostics folders.

## This diff
- Strips FBCrashLogNotifier of FSEvents logic, and funnels everything into a `resolveUntil` block which is effectively polling the known diagnostics locations.
- Fixes a bug(?) where the polling implementation wasn't handling the `onlyNew` flag. I don't think this is an issue in practice as I'm not seeing anywhere in the code where we actually want to collect older crashlogs.
- Updates the FBSimulatorControlTests to target MacOSX, and replaces the assertion for iPhone8 to iPhone16 (which is something we actually have).

Differential Revision: D68713530

fbshipit-source-id: 1d9907af3dbf2da51de345d1c58cb0d2457062d0

Author: cpepin

FBControlCore/Crashes/FBCrashLogNotifier.m

@@ -13,133 +13,9 @@
 #import "FBControlCoreLogger.h"
 #import "FBControlCoreError.h"
 
-#if defined(__apple_build_version__)
-
-#import <CoreServices/CoreServices.h>
-#include <sys/stat.h>
-
-@interface FBCrashLogNotifier_FSEvents : NSObject
-
-@property (nonatomic, copy, readonly) NSArray<NSString *> *directories;
-@property (nonatomic, strong, readonly) FBCrashLogStore *store;
-@property (nonatomic, strong, readonly) id<FBControlCoreLogger> logger;
-@property (nonatomic, strong, readonly) dispatch_queue_t queue;
-@property (nonatomic, assign, readwrite) FSEventStreamRef eventStream;
-
-@end
-
-typedef NS_ENUM(NSUInteger, FBCrashLogNotifierFileEvent) {
-  FBCrashLogNotifierFileEventUnknown = 0,
-  FBCrashLogNotifierFileEventAdded = 1,
-  FBCrashLogNotifierFileEventRemoved = 2,
-};
-
-static FBCrashLogNotifierFileEvent GetEventType(FSEventStreamEventFlags flag, NSString *filePath) {
-  if (flag & kFSEventStreamEventFlagItemRemoved) {
-    return FBCrashLogNotifierFileEventRemoved;
-  } else if (flag & kFSEventStreamEventFlagItemCreated) {
-    return FBCrashLogNotifierFileEventAdded;
-  } else if (flag & kFSEventStreamEventFlagItemRenamed) {
-    struct stat buffer;
-    int value = stat(filePath.UTF8String, &buffer);
-    return value == 0 ? FBCrashLogNotifierFileEventAdded : FBCrashLogNotifierFileEventRemoved;
-  }
-  return FBCrashLogNotifierFileEventUnknown;
-}
-
-static void EventStreamCallback(
-  ConstFSEventStreamRef streamRef,
-  FBCrashLogNotifier_FSEvents *notifier,
-  size_t numEvents,
-  NSArray<NSString *> *eventPaths,
-  const FSEventStreamEventFlags *eventFlags,
-  const FSEventStreamEventId *eventIds
-){
-  for (size_t index = 0; index < numEvents; index++) {
-    NSString *path = eventPaths[index];
-    FSEventStreamEventFlags flag = eventFlags[index];
-    switch (GetEventType(flag, path)) {
-      case FBCrashLogNotifierFileEventAdded:
-        [notifier.store ingestCrashLogAtPath:path];
-        continue;
-      case FBCrashLogNotifierFileEventRemoved:
-        [notifier.store removeCrashLogAtPath:path];
-        continue;
-      default:
-        continue;
-    }
-  }
-}
-
-@implementation FBCrashLogNotifier_FSEvents
-
-- (instancetype)initWithDirectories:(NSArray<NSString *> *)directories store:(FBCrashLogStore *)store logger:(id<FBControlCoreLogger>)logger
-{
-  self = [super init];
-  if (!self) {
-    return nil;
-  }
-
-  _directories = directories;
-  _store = store;
-  _logger = logger;
-  _queue = dispatch_queue_create("com.facebook.fbcontrolcore.crash_logs.fsevents", DISPATCH_QUEUE_SERIAL);
-
-  return self;
-}
-
-- (BOOL)startListening:(BOOL)onlyNew
-{
-  if (self.eventStream) {
-    return YES;
-  }
-
-  FSEventStreamContext context = {
-    .version = 0,
-    .info = (void *) CFBridgingRetain(self),
-    .retain = CFRetain,
-    .release = CFRelease,
-    .copyDescription = NULL,
-  };
-
-  NSMutableArray<NSString *> *pathsToWatch = NSMutableArray.array;
-  for (NSString *reportPath in self.directories) {
-    if ([[NSFileManager defaultManager] fileExistsAtPath:reportPath]) {
-      [pathsToWatch addObject:reportPath];
-    }
-  }
-
-  FSEventStreamRef eventStream = FSEventStreamCreate(
-    NULL, // Allocator
-    (FSEventStreamCallback) EventStreamCallback, // Callback
-    &context,  // Context
-    CFBridgingRetain(pathsToWatch), // Paths to watch
-    onlyNew ? kFSEventStreamEventIdSinceNow : 0,  // Since When
-    0,  // Latency
-    kFSEventStreamCreateFlagUseCFTypes | kFSEventStreamCreateFlagFileEvents | kFSEventStreamCreateFlagNoDefer
-  );
-  FSEventStreamSetDispatchQueue(eventStream, self.queue);
-  Boolean started = FSEventStreamStart(eventStream);
-  if (!started) {
-    NSLog(@"FS Event Stream could not be started");
-    return NO;
-  }
-
-  self.eventStream = eventStream;
-  return YES;
-}
-
-@end
-
-#endif
-
 @interface FBCrashLogNotifier ()
 
-#if defined(__apple_build_version__)
-@property (nonatomic, strong, readonly) FBCrashLogNotifier_FSEvents *fsEvents;
-#else
 @property (nonatomic, copy, readwrite) NSDate *sinceDate;
-#endif
 
 @end
 
@@ -155,12 +31,7 @@ - (instancetype)initWithLogger:(id<FBControlCoreLogger>)logger
   }
 
   _store = [FBCrashLogStore storeForDirectories:FBCrashLogInfo.diagnosticReportsPaths logger:logger];
-
-#if defined(__apple_build_version__)
-  _fsEvents = [[FBCrashLogNotifier_FSEvents alloc] initWithDirectories:FBCrashLogInfo.diagnosticReportsPaths store:_store logger:logger];
-#else
   _sinceDate = NSDate.date;
-#endif
 
   return self;
 }
@@ -179,12 +50,8 @@ + (instancetype)sharedInstance
 
 - (BOOL)startListening:(BOOL)onlyNew
 {
-#if defined(__apple_build_version__)
-  return [self.fsEvents startListening:onlyNew];
-#else
-  self.sinceDate = NSDate.date;
+  self.sinceDate = onlyNew ? NSDate.date : [NSDate distantPast];
   return YES;
-#endif
 }
 
 - (FBFuture<FBCrashLogInfo *> *)nextCrashLogForPredicate:(NSPredicate *)predicate
@@ -195,9 +62,6 @@ - (BOOL)startListening:(BOOL)onlyNew
       failFuture];
   }
 
-#if defined(__apple_build_version__)
-  return [FBCrashLogNotifier.sharedInstance.fsEvents.store nextCrashLogForMatchingPredicate:predicate];
-#else
   dispatch_queue_t queue = dispatch_queue_create("com.facebook.fbcontrolcore.crashlogfetch", DISPATCH_QUEUE_SERIAL);
   return [FBFuture
    onQueue:queue resolveUntil:^{
@@ -210,9 +74,9 @@ - (BOOL)startListening:(BOOL)onlyNew
          describeFormat:@"Crash Log Info for %@ could not be obtained", predicate]
          failFuture];
      }
+     [self.store ingestCrashLogAtPath:crashInfo.crashPath];
      return [FBFuture futureWithResult:crashInfo];
    }];
-#endif
 }
 
 @end

FBSimulatorControlTests/Tests/Integration/FBSimulatorCrashLogTests.m

@@ -51,7 +51,7 @@ - (void)testAppCrashLogIsFetched
   XCTAssertNil(error);
   XCTAssertNotNil(crashLog);
   XCTAssertEqualObjects(crashLog.identifier, @"TableSearch");
-  XCTAssertTrue([[NSString stringWithContentsOfFile:crashLog.crashPath encoding:NSUTF8StringEncoding error:nil] containsString:@"NSFileManager stringWithFormat"]);
+  XCTAssertTrue([[NSString stringWithContentsOfFile:crashLog.crashPath encoding:NSUTF8StringEncoding error:&error] containsString:@"\"app_name\":\"TableSearch\""]);
 }
 
 @end

FBSimulatorControlTests/Utilities/FBSimulatorControlTestCase.m

@@ -105,7 +105,7 @@ + (FBSimulatorBootConfiguration *)defaultBootConfiguration
 - (void)setUp
 {
   self.continueAfterFailure = NO;
-  self.simulatorConfiguration = [FBSimulatorConfiguration.defaultConfiguration withDeviceModel:FBDeviceModeliPhone8];
+  self.simulatorConfiguration = [FBSimulatorConfiguration.defaultConfiguration withDeviceModel:FBDeviceModeliPhone16];
   self.bootConfiguration = [[FBSimulatorBootConfiguration alloc] initWithOptions:FBSimulatorControlTestCase.bootOptions environment:@{}];
   self.deviceSetPath = FBSimulatorControlTestCase.defaultDeviceSetPath;
 }