// 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 }