// Editor initiates the contract revision process with a host, and returns
// an Editor.
func (c *Contractor) Editor(contract modules.RenterContract) (Editor, error) {
c.mu.RLock()
height := c.blockHeight
c.mu.RUnlock()
if height > contract.EndHeight() {
return nil, errors.New("contract has already ended")
}
host, ok := c.hdb.Host(contract.NetAddress)
if !ok {
return nil, errors.New("no record of that host")
}
if host.StoragePrice.Cmp(maxStoragePrice) > 0 {
return nil, errTooExpensive
}
// cap host.Collateral on new hosts
if build.VersionCmp(host.Version, "0.6.0") > 0 {
if host.Collateral.Cmp(maxUploadCollateral) > 0 {
host.Collateral = maxUploadCollateral
}
}
// create editor
e, err := proto.NewEditor(host, contract, height)
if proto.IsRevisionMismatch(err) {
// try again with the cached revision
c.mu.RLock()
cached, ok := c.cachedRevisions[contract.ID]
c.mu.RUnlock()
if !ok {
// nothing we can do; return original error
return nil, err
}
c.log.Printf("host %v has different revision for %v; retrying with cached revision", contract.NetAddress, contract.ID)
contract.LastRevision = cached.revision
contract.MerkleRoots = cached.merkleRoots
e, err = proto.NewEditor(host, contract, height)
}
if err != nil {
return nil, err
}
// supply a SaveFn that saves the revision to the contractor's persist
// (the existing revision will be overwritten when SaveFn is called)
e.SaveFn = c.saveRevision(contract.ID)
return &hostEditor{
editor: e,
contract: contract,
contractor: c,
}, nil
}
// Downloader initiates the download request loop with a host, and returns a
// Downloader.
func (c *Contractor) Downloader(contract modules.RenterContract) (Downloader, error) {
c.mu.RLock()
height := c.blockHeight
c.mu.RUnlock()
if height > contract.EndHeight() {
return nil, errors.New("contract has already ended")
}
host, ok := c.hdb.Host(contract.NetAddress)
if !ok {
return nil, errors.New("no record of that host")
}
if host.DownloadBandwidthPrice.Cmp(maxDownloadPrice) > 0 {
return nil, errTooExpensive
}
// create downloader
d, err := proto.NewDownloader(host, contract)
if proto.IsRevisionMismatch(err) {
// try again with the cached revision
c.mu.RLock()
cached, ok := c.cachedRevisions[contract.ID]
c.mu.RUnlock()
if !ok {
// nothing we can do; return original error
return nil, err
}
c.log.Printf("host %v has different revision for %v; retrying with cached revision", contract.NetAddress, contract.ID)
contract.LastRevision = cached.revision
d, err = proto.NewDownloader(host, contract)
}
if err != nil {
return nil, err
}
// supply a SaveFn that saves the revision to the contractor's persist
// (the existing revision will be overwritten when SaveFn is called)
d.SaveFn = c.saveRevision(contract.ID)
return &hostDownloader{
downloader: d,
contractor: c,
}, nil
}