github.com/macb/etcd@v0.3.1-0.20140227003422-a60481c6b1a0/store/command_factory.go (about)

     1  package store
     2  
     3  import (
     4  	"fmt"
     5  	"time"
     6  
     7  	"github.com/coreos/etcd/third_party/github.com/coreos/raft"
     8  )
     9  
    10  // A lookup of factories by version.
    11  var factories = make(map[int]CommandFactory)
    12  var minVersion, maxVersion int
    13  
    14  // The CommandFactory provides a way to create different types of commands
    15  // depending on the current version of the store.
    16  type CommandFactory interface {
    17  	Version() int
    18  	CreateUpgradeCommand() raft.Command
    19  	CreateSetCommand(key string, dir bool, value string, expireTime time.Time) raft.Command
    20  	CreateCreateCommand(key string, dir bool, value string, expireTime time.Time, unique bool) raft.Command
    21  	CreateUpdateCommand(key string, value string, expireTime time.Time) raft.Command
    22  	CreateDeleteCommand(key string, dir, recursive bool) raft.Command
    23  	CreateCompareAndSwapCommand(key string, value string, prevValue string,
    24  		prevIndex uint64, expireTime time.Time) raft.Command
    25  	CreateCompareAndDeleteCommand(key string, prevValue string, prevIndex uint64) raft.Command
    26  	CreateSyncCommand(now time.Time) raft.Command
    27  }
    28  
    29  // RegisterCommandFactory adds a command factory to the global registry.
    30  func RegisterCommandFactory(factory CommandFactory) {
    31  	version := factory.Version()
    32  
    33  	if GetCommandFactory(version) != nil {
    34  		panic(fmt.Sprintf("Command factory already registered for version: %d", factory.Version()))
    35  	}
    36  
    37  	factories[version] = factory
    38  
    39  	// Update compatibility versions.
    40  	if minVersion == 0 || version > minVersion {
    41  		minVersion = version
    42  	}
    43  	if maxVersion == 0 || version > maxVersion {
    44  		maxVersion = version
    45  	}
    46  }
    47  
    48  // GetCommandFactory retrieves a command factory for a given command version.
    49  func GetCommandFactory(version int) CommandFactory {
    50  	return factories[version]
    51  }
    52  
    53  // MinVersion returns the minimum compatible store version.
    54  func MinVersion() int {
    55  	return minVersion
    56  }
    57  
    58  // MaxVersion returns the maximum compatible store version.
    59  func MaxVersion() int {
    60  	return maxVersion
    61  }