strings.go

package redis

import (
    "strconv"
    "sync"
)

var (
    allStrings map[string]string = make(map[string]string)
    stringsMu  sync.RWMutex
)

// Set key to hold the string value. If key already holds a value, it
// is overwritten, regardless of its type. Any previous time to live
// associated with the key is discarded on successful SET operation.
func Set(key, value string) string {
    stringsMu.Lock()
    defer stringsMu.Unlock()

    allStrings[key] = value

    publish <- notice{"string", key, "", allStrings[key]}

    return "OK"
}

// Get the value of key. If the key does not exist the special value nil
// is returned. An error is returned if the value stored at key is not a
// string, because GET only handles string values.
//
// Return value
// Bulk string reply: the value of key, or nil when key does not exist.
func Get(key string) string {
    stringsMu.RLock()
    defer stringsMu.RUnlock()

    return allStrings[key]
}

// Set key to hold string value if key does not exist. In that case,
// it is equal to SET. When key already holds a value, no operation
// is performed. SETNX is short for "SET if N ot e X ists".
//
// Return value
// Integer reply, specifically:
// 1 if the key was set
// 0 if the key was not set
func Setnx(key, value string) int {
    stringsMu.Lock()
    defer stringsMu.Unlock()

    _, exists := allStrings[key]
    if exists {
        return 0
    }
    allStrings[key] = value

    publish <- notice{"string", key, "", allStrings[key]}

    return 1
}

// Increments the number stored at key by one. If the key does not exist,
// it is set to 0 before performing the operation. An error is returned
// if the key contains a value of the wrong type or contains a string
// that can not be represented as integer.
//
// Return value
// String reply: the value of key after the increment
func Incr(key string) string {
    stringsMu.Lock()
    defer stringsMu.Unlock()

    val, exists := allStrings[key]
    if !exists {
        val = "0"
    }
    i, _ := strconv.Atoi(val)
    allStrings[key] = strconv.Itoa(i + 1)

    publish <- notice{"string", key, "", allStrings[key]}

    return allStrings[key]
}

// Decrements the number stored at key by one. If the key does not exist, it is set to 0 before performing the operation. An error is returned if the key contains a value of the wrong type or contains a string that can not be represented as integer. This operation is limited to 64 bit signed integers.
// See INCR for extra information on increment/decrement operations.
//
// Return value
// String reply: the value of key after the decrement
func Decr(key string) string {
    stringsMu.Lock()
    defer stringsMu.Unlock()

    val, exists := allStrings[key]
    if !exists {
        val = "0"
    }
    i, _ := strconv.Atoi(val)
    allStrings[key] = strconv.Itoa(i - 1)

    publish <- notice{"string", key, "", allStrings[key]}

    return allStrings[key]
}