package types // nolint: goimports
import (
context "golang.org/x/net/context"
)
// Application is an interface that enables any finite, deterministic state machine
// to be driven by a blockchain-based replication engine via the ABCI.
// All methods take a RequestXxx argument and return a ResponseXxx argument,
// except CheckTx/DeliverTx, which take `tx []byte`, and `Commit`, which takes nothing.
type Application interface {
// Info/Query Connection
Info(RequestInfo) ResponseInfo // Return application info
SetOption(RequestSetOption) ResponseSetOption // Set application option
Query(RequestQuery) ResponseQuery // Query for state
// Mempool Connection
CheckTx(tx []byte) ResponseCheckTx // Validate a tx for the mempool
// Consensus Connection
InitChain(RequestInitChain) ResponseInitChain // Initialize blockchain with validators and other info from TendermintCore
BeginBlock(RequestBeginBlock) ResponseBeginBlock // Signals the beginning of a block
DeliverTx(tx []byte) ResponseDeliverTx // Deliver a tx for full processing
EndBlock(RequestEndBlock) ResponseEndBlock // Signals the end of a block, returns changes to the validator set
Commit() ResponseCommit // Commit the state and return the application Merkle root hash
}
//-------------------------------------------------------
// BaseApplication is a base form of Application
var _ Application = (*BaseApplication)(nil)
type BaseApplication struct {
}
func NewBaseApplication() *BaseApplication {
return &BaseApplication{}
}
func (BaseApplication) Info(req RequestInfo) ResponseInfo {
return ResponseInfo{}
}
func (BaseApplication) SetOption(req RequestSetOption) ResponseSetOption {
return ResponseSetOption{}
}
func (BaseApplication) DeliverTx(tx []byte) ResponseDeliverTx {
return ResponseDeliverTx{Code: CodeTypeOK}
}
func (BaseApplication) CheckTx(tx []byte) ResponseCheckTx {
return ResponseCheckTx{Code: CodeTypeOK}
}
func (BaseApplication) Commit() ResponseCommit {
return ResponseCommit{}
}
func (BaseApplication) Query(req RequestQuery) ResponseQuery {
return ResponseQuery{Code: CodeTypeOK}
}
func (BaseApplication) InitChain(req RequestInitChain) ResponseInitChain {
return ResponseInitChain{}
}
func (BaseApplication) BeginBlock(req RequestBeginBlock) ResponseBeginBlock {
return ResponseBeginBlock{}
}
func (BaseApplication) EndBlock(req RequestEndBlock) ResponseEndBlock {
return ResponseEndBlock{}
}
//-------------------------------------------------------
// GRPCApplication is a GRPC wrapper for Application
type GRPCApplication struct {
app Application
}
func NewGRPCApplication(app Application) *GRPCApplication {
return &GRPCApplication{app}
}
func (app *GRPCApplication) Echo(ctx context.Context, req *RequestEcho) (*ResponseEcho, error) {
return &ResponseEcho{req.Message}, nil
}
func (app *GRPCApplication) Flush(ctx context.Context, req *RequestFlush) (*ResponseFlush, error) {
return &ResponseFlush{}, nil
}
func (app *GRPCApplication) Info(ctx context.Context, req *RequestInfo) (*ResponseInfo, error) {
res := app.app.Info(*req)
return &res, nil
}
func (app *GRPCApplication) SetOption(ctx context.Context, req *RequestSetOption) (*ResponseSetOption, error) {
res := app.app.SetOption(*req)
return &res, nil
}
func (app *GRPCApplication) DeliverTx(ctx context.Context, req *RequestDeliverTx) (*ResponseDeliverTx, error) {
res := app.app.DeliverTx(req.Tx)
return &res, nil
}
func (app *GRPCApplication) CheckTx(ctx context.Context, req *RequestCheckTx) (*ResponseCheckTx, error) {
res := app.app.CheckTx(req.Tx)
return &res, nil
}
func (app *GRPCApplication) Query(ctx context.Context, req *RequestQuery) (*ResponseQuery, error) {
res := app.app.Query(*req)
return &res, nil
}
func (app *GRPCApplication) Commit(ctx context.Context, req *RequestCommit) (*ResponseCommit, error) {
res := app.app.Commit()
return &res, nil
}
func (app *GRPCApplication) InitChain(ctx context.Context, req *RequestInitChain) (*ResponseInitChain, error) {
res := app.app.InitChain(*req)
return &res, nil
}
func (app *GRPCApplication) BeginBlock(ctx context.Context, req *RequestBeginBlock) (*ResponseBeginBlock, error) {
res := app.app.BeginBlock(*req)
return &res, nil
}
func (app *GRPCApplication) EndBlock(ctx context.Context, req *RequestEndBlock) (*ResponseEndBlock, error) {
res := app.app.EndBlock(*req)
return &res, nil
}
var _ Application = (*BaseApplication)(nil)
这一句比较难懂。先从右侧开始：(*BaseApplication)(nil)是把一个nil强制转化成BaseApplication的指针。
其次是左侧，var _ Application定义了一个不计名的变量，这个变量实现了Application接口。
因为BaseApplication实现了Application里的所有函数，因此，右侧的值可以赋给左侧。