Define a static method, for escape string

new_gist_file

static NSString* GAEscapeNSString(NSString* value) {
    if (!value) return nil;
    const char *chars = [value UTF8String];
    NSMutableString *escapedString = [NSMutableString string];
    while (*chars) {
        if (*chars == '\\') {
            [escapedString appendString:@"\\\\"];
        } else if (*chars == '\'') {
            [escapedString appendString:@"\\'"];
        } else {
            [escapedString appendFormat:@"%c", *chars];
        }
        ++chars;
    }
    return escapedString;
}