Upload files to "c2s_ipfs_payloads/pkg"

c2s_ipfs_payloads/pkg/contract.go

@@ -0,0 +1,60 @@
+// Package contract handles smart contract interaction for the fully
+// decentralized CID feed mode (MODE B).
+//
+// This file only contains the interface. The actual implementation requires
+// go-ethereum and is in contract_eth.go (build tag: ethereum).
+package contract
+
+import "errors"
+
+// CIDEvent represents a NewCID event emitted by the smart contract.
+type CIDEvent struct {
+	CID       string
+	Sender    string
+	Timestamp uint64
+	BlockNum  uint64
+	TxHash    string
+}
+
+// Watcher watches a smart contract for NewCID events.
+type Watcher interface {
+	// Watch starts watching for new CID events. The callback is called
+	// for each event. Returns a channel that receives an error on failure.
+	Watch(callback func(CIDEvent)) (<-chan error, error)
+
+	// GetLatestCID fetches the current CID from the contract.
+	GetLatestCID() (string, error)
+
+	// SendCID submits a new CID to the contract (requires wallet).
+	SendCID(cid string, privateKeyHex string) (string, error)
+
+	// Close cleans up the watcher.
+	Close()
+}
+
+// ErrNotCompiledWithEthereum is returned when the binary is not built with
+// the ethereum build tag.
+var ErrNotCompiledWithEthereum = errors.New("not compiled with -tags ethereum; rebuild with: go build -tags ethereum")
+
+// PlaceholderWatcher returns errors requiring go-ethereum.
+type PlaceholderWatcher struct{}
+
+func (p *PlaceholderWatcher) Watch(callback func(CIDEvent)) (<-chan error, error) {
+	return nil, ErrNotCompiledWithEthereum
+}
+
+func (p *PlaceholderWatcher) GetLatestCID() (string, error) {
+	return "", ErrNotCompiledWithEthereum
+}
+
+func (p *PlaceholderWatcher) SendCID(cid, privateKeyHex string) (string, error) {
+	return "", ErrNotCompiledWithEthereum
+}
+
+func (p *PlaceholderWatcher) Close() {}
+
+// NewWatcher creates a contract watcher. If go-ethereum is not available,
+// returns a placeholder that errors.
+var NewWatcher func(rpcURL, contractAddr string) (Watcher, error) = func(rpcURL, contractAddr string) (Watcher, error) {
+	return &PlaceholderWatcher{}, ErrNotCompiledWithEthereum
+}