Generate live crash report using PLCrashReporter

CrashManager

@interface CrashManager:NSObject
/**
 * Generates live crash report, without triggering an actual crash condition. 
 * 
 * Works only if the vendor SDK is built using PLCrashReporter v 1.1 atleast.
 * We are using runtime magic to call generateLiveReportAndReturnError: method on PLCrashReporter instance without changing vendor sdk (QuincyKit, HockeyApp, others)
 */
- (void)generateLiveReport;
@end

@implementation CrashManager

- (void)generateLiveReport
{
    Class plCrashReporter = [NSClassFromString(@"PLCrashReporter") class];
    
    SEL sharedReporterSel = @selector(sharedReporter);
    SEL generateLiveReportSel = @selector(generateLiveReportAndReturnError:);
    
    if([plCrashReporter respondsToSelector:sharedReporterSel])
    {
        id plIn = objc_msgSend(plCrashReporter, @selector(sharedReporter));
        if([plIn respondsToSelector:generateLiveReportSel])
        {
            NSError *err = nil;
            NSData *data = objc_msgSend(plIn, @selector(generateLiveReportAndReturnError:),&err);
            saveLiveReportForData(data);
            //printLiveReportForData(data);
        }
    }
}
@end


/* Helper method to write data to file .plcrash that we can use to symbolicate on local mac */

static NSString *WATCHDOG_REPORT_DIR = @"WatchdogLogs";
static NSUInteger MAX_FILES = 10;

static void saveLiveReportForData (NSData *data)
{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    /*Setup directory attributes 755*/
    NSDictionary *attributes = [NSDictionary dictionaryWithObject:[NSNumber numberWithUnsignedLong:0755] forKey:NSFilePosixPermissions];
    
    NSError *error = nil;
    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    if(![fileManager createDirectoryAtPath: documentsDirectory withIntermediateDirectories:YES attributes:attributes error:&error])
    {
        NSLog(@"Could not create documents directory: %@", error);
        return;
    }
    /* Create Watchdog logs directory that we will use to save the watchdog reports */
    NSString *watchdogLogsDirectory = [documentsDirectory stringByAppendingPathComponent:WATCHDOG_REPORT_DIR];
    if (![fileManager fileExistsAtPath:watchdogLogsDirectory])
    {
        [fileManager createDirectoryAtPath:watchdogLogsDirectory withIntermediateDirectories:NO attributes:attributes error:&error];
    }
    
    NSArray *watchdogDirectoryContent = [fileManager contentsOfDirectoryAtURL:[NSURL fileURLWithPath:watchdogLogsDirectory isDirectory:YES]
                                                   includingPropertiesForKeys:@[NSURLContentModificationDateKey]
                                                                      options:NSDirectoryEnumerationSkipsHiddenFiles
                                                                        error:nil];
    
    NSArray *sortedDirectoryContent = [watchdogDirectoryContent sortedArrayUsingComparator:^(NSURL *file1, NSURL *file2){
        // compare
        NSDate *file1Date;
        [file1 getResourceValue:&file1Date forKey:NSURLContentModificationDateKey error:nil];
        
        NSDate *file2Date;
        [file2 getResourceValue:&file2Date forKey:NSURLContentModificationDateKey error:nil];
        
        return [file1Date compare:file2Date];
    }];
    /* Remove the first untouched file from the directory contents if the cached reports count reaches max_count*/
    if([sortedDirectoryContent count] >= MAX_FILES)
    {
        [fileManager removeItemAtPath:[sortedDirectoryContent objectAtIndex:0] error:nil];
    }
    
    /* Get current date/timestamp that we are going to append to file name as suffix before extension*/
    NSDate *today = [NSDate date];
    NSDateFormatter *dateFormatter = [NSDateFormatter new];
    [dateFormatter setDateFormat:@"dd-MM-yyyy-hh-mm-ss"];
    NSString *timeString = [dateFormatter stringFromDate:today];
    
    NSString *fileName = [NSString stringWithFormat:@"watchdog_report_%@.plcrash",timeString];
    NSString *outputPath = [watchdogLogsDirectory stringByAppendingPathComponent:fileName];
    if(![data writeToFile:outputPath atomically:YES])
    {
        NSLog(@"Failed to write crash report");
    }
    
    NSLog(@"Saved crash report to: %@", outputPath);
}

/* Prints human readable crash report. Use this for debugging purpose only*/
static void printLiveReportForData (NSData *data)
{
    Class plCrashReport = [NSClassFromString(@"PLCrashReport") class];
    Class plCrashReportTextFormatter = [NSClassFromString(@"PLCrashReportTextFormatter") class];
    
    SEL initWithDataSelector = @selector(initWithData:error:);
    SEL stringValueForCrashReportSelector = @selector(stringValueForCrashReport:withTextFormat:);
    
    if([plCrashReport respondsToSelector:initWithDataSelector])
    {
        id classReport = objc_msgSend([plCrashReport alloc], initWithDataSelector,data,nil);
        
        if([plCrashReportTextFormatter respondsToSelector:stringValueForCrashReportSelector])
        {
            NSString * crashReportText = objc_msgSend(plCrashReportTextFormatter, stringValueForCrashReportSelector,classReport,0);
            NSLog(@"%@",crashReportText);
        }
    }
}