FlutterJSONMessageCodec Class Reference

#include <FlutterCodecs.h>

Inheritance diagram for FlutterJSONMessageCodec:

Instance Methods
(NSData *)	- encode: [implementation]
(id)	- decode: [implementation]
Instance Methods inherited from <FlutterMessageCodec>
(NSData *_Nullable)	- encode:
(id _Nullable)	- decode:

Class Methods
(instancetype)	+ sharedInstance [implementation]

Detailed Description

A FlutterMessageCodec using UTF-8 encoded JSON messages.

This codec is guaranteed to be compatible with the corresponding JSONMessageCodec on the Dart side. These parts of the Flutter SDK are evolved synchronously.

Supports values accepted by NSJSONSerialization plus top-level nil, NSNumber, and NSString.

On the Dart side, JSON messages are handled by the JSON facilities of the dart:convert package.

Definition at line 81 of file FlutterCodecs.h.

Method Documentation

decode:

- (id) decode: (NSData*)  message

implementation

Definition at line 9 of file FlutterCodecs.mm.

            :(NSData*)message {
  if ([message length] == 0) {
    return nil;
  }
  BOOL isSimpleValue = NO;
  id decoded = nil;
  NSError* error;
  if (0 < message.length) {
    UInt8 first;
    [message getBytes:&first length:1];
    isSimpleValue = first != '{' && first != '[';
    if (isSimpleValue) {
      // NSJSONSerialization does not support top-level simple values.
      // We expand encoding to singleton array, then decode that and extract
      // the single entry.
      UInt8 begin = '[';
      UInt8 end = ']';
      NSMutableData* expandedMessage = [NSMutableData dataWithLength:message.length + 2];
      [expandedMessage replaceBytesInRange:NSMakeRange(0, 1) withBytes:&begin];
      [expandedMessage replaceBytesInRange:NSMakeRange(1, message.length) withBytes:message.bytes];
      [expandedMessage replaceBytesInRange:NSMakeRange(message.length + 1, 1) withBytes:&end];
      message = expandedMessage;
    }
    decoded = [NSJSONSerialization JSONObjectWithData:message options:0 error:&error];
  }
  NSAssert(decoded, @"Invalid JSON message, decoding failed: %@", error);
  return isSimpleValue ? ((NSArray*)decoded)[0] : decoded;
}

encode:

- (NSData *) encode: (id)  message

implementation

Definition at line 9 of file FlutterCodecs.mm.

                 :(id)message {
  if (message == nil) {
    return nil;
  }
  NSData* encoding;
  NSError* error;
  if ([message isKindOfClass:[NSArray class]] || [message isKindOfClass:[NSDictionary class]]) {
    encoding = [NSJSONSerialization dataWithJSONObject:message options:0 error:&error];
  } else {
    // NSJSONSerialization does not support top-level simple values.
    // We encode as singleton array, then extract the relevant bytes.
    encoding = [NSJSONSerialization dataWithJSONObject:@[ message ] options:0 error:&error];
    if (encoding) {
      encoding = [encoding subdataWithRange:NSMakeRange(1, encoding.length - 2)];
    }
  }
  NSAssert(encoding, @"Invalid JSON message, encoding failed: %@", error);
  return encoding;
}

sharedInstance

+ (instancetype) sharedInstance

implementation

Returns a shared instance of this FlutterMessageCodec.

Reimplemented from <FlutterMessageCodec>.

Definition at line 9 of file FlutterCodecs.mm.

                               {
  static id _sharedInstance = nil;
  if (!_sharedInstance) {
    _sharedInstance = [[FlutterJSONMessageCodec alloc] init];
  }
  return _sharedInstance;
}

---

The documentation for this class was generated from the following files:

• shell/platform/darwin/common/framework/Headers/FlutterCodecs.h
• shell/platform/darwin/common/framework/Source/FlutterCodecs.mm