cmd_zadd.go

cmd_zadd.go - Overview

This file defines the ZADD command, which adds members with specified scores to a sorted set. It includes the command's metadata, evaluation logic, and execution logic within a sharded environment.

Detailed Documentation

cZADD

var cZADD = &CommandMeta{
	Name:      "ZADD",
	Syntax:    "ZADD key [NX | XX] [GT | LT] [CH] [INCR] score member [score member...]",
	HelpShort: "ZADD adds all the specified members with the specified scores to the sorted set stored at key",
	HelpLong: `
ZADD adds all the specified members with the specified scores to the sorted set stored at key

- NX: Only add new elements and do not update existing elements
- XX: Only update existing elements and do not add new elements
- GT: Only add new elements if the score is greater than the existing score
- LT: Only add new elements if the score is less than the existing score
- CH: Modify the return value from the number of new elements added to the total number of elements changed
- INCR: When this option is specified, the scores provided are treated as increments to the score of the existing elements

The command by default returns the number of elements added to the sorted set.
	`,
	Examples: `
localhost:7379> ZADD users 10 u1
OK 1
localhost:7379> ZADD users 5 u2
OK 1
localhost:7379> ZADD users 15 u3
OK 1
localhost:7379> ZADD users 12 u4
OK 1
localhost:7379> ZADD users 10 u1
OK 0
localhost:7379> ZADD users CH 11 u1
OK 1
`,
	Eval:    evalZADD,
	Execute: executeZADD,
}

• Purpose: Defines the metadata for the ZADD command, including its name, syntax, help messages, examples, and the functions to evaluate and execute the command.
• Parameters:
  • Name: The name of the command ("ZADD").
  • Syntax: The command's syntax.
  • HelpShort: A short description of the command.
  • HelpLong: A detailed description of the command and its options.
  • Examples: Examples of how to use the command.
  • Eval: The function to evaluate the command (evalZADD).
  • Execute: The function to execute the command (executeZADD).
• Returns: None.

init()

func init() {
	CommandRegistry.AddCommand(cZADD)
}

• Purpose: Registers the ZADD command with the CommandRegistry.
• Parameters: None
• Returns: None

evalZADD(c *Cmd, s *dsstore.Store) (*CmdRes, error)

func evalZADD(c *Cmd, s *dsstore.Store) (*CmdRes, error) {
	if len(c.C.Args) < 3 {
		return cmdResNil, errors.ErrWrongArgumentCount("ZADD")
	}

	key := c.C.Args[0]
	scores, members := []int64{}, []string{}
	params, nonParams := parseParams(c.C.Args[1:])

	if len(nonParams)%2 != 0 {
		return cmdResNil, errors.ErrWrongArgumentCount("ZADD")
	}

	for i := 0; i < len(nonParams); i += 2 {
		score, err := strconv.ParseInt(nonParams[i], 10, 64)
		if err != nil {
			return cmdResNil, errors.ErrInvalidNumberFormat
		}
		scores = append(scores, score)
		members = append(members, nonParams[i+1])
	}

	var ss *types.SortedSet
	obj := s.Get(key)
	if obj == nil {
		ss = types.NewSortedSet()
		s.Put(key, s.NewObj(ss, -1, object.ObjTypeSortedSet), dsstore.WithPutCmd(dsstore.ZAdd))
	} else {
		if obj.Type != object.ObjTypeSortedSet {
			return cmdResNil, errors.ErrWrongTypeOperation
		}
		ss = obj.Value.(*types.SortedSet)
	}

	// Note: Validation of the params is done in the types.SortedSet.ZADD method
	count, err := ss.ZADD(scores, members, params)
	if err != nil {
		return cmdResNil, err
	}
	return cmdResInt(count), nil
}

• Purpose: Evaluates the ZADD command, parsing arguments, retrieving or creating a sorted set, and adding members with their scores to the set.
• Parameters:
  • c: A pointer to the Cmd struct representing the command.
  • s: A pointer to the dsstore.Store struct representing the data store.
• Returns:
  • *CmdRes: A pointer to the CmdRes struct representing the command result.
  • error: An error if any occurred.

executeZADD(c *Cmd, sm *shardmanager.ShardManager) (*CmdRes, error)

func executeZADD(c *Cmd, sm *shardmanager.ShardManager) (*CmdRes, error) {
	if len(c.C.Args) < 3 {
		return cmdResNil, errors.ErrWrongArgumentCount("ZADD")
	}

	shard := sm.GetShardForKey(c.C.Args[0])
	return evalZADD(c, shard.Thread.Store())
}

• Purpose: Executes the ZADD command within a sharded environment by retrieving the appropriate shard and calling evalZADD on that shard's store.
• Parameters:
  • c: A pointer to the Cmd struct representing the command.
  • sm: A pointer to the shardmanager.ShardManager struct representing the shard manager.
• Returns:
  • *CmdRes: A pointer to the CmdRes struct representing the command result.
  • error: An error if any occurred.

Code Examples

None.

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