Blockchain: blockchain.IterateDeleteRecord decode all records at once, fixing multiple issues with file tags that could result in corrupted or orphaned records. Fix #66, fix #37, fix #38

blockchain/Blockchain.go

@@ -171,7 +171,7 @@ func (blockchain *Blockchain) Iterate(callback func(block *Block) int) (status i
 // IterateDeleteRecord iterates over the blockchain to find records to delete. Status is StatusX.
 // deleteAction is 0 = no action on record, 1 = delete record, 2 = replace record, 3 = error blockchain corrupt
 // If the callback returns true, the record will be deleted. The blockchain will be automatically refactored and height and version updated.
-func (blockchain *Blockchain) IterateDeleteRecord(callback func(record *BlockRecordRaw) (deleteAction int)) (newHeight, newVersion uint64, status int) {
+func (blockchain *Blockchain) IterateDeleteRecord(callbackFile func(file *BlockRecordFile) (deleteAction int), callbackOther func(record *BlockRecordRaw) (deleteAction int)) (newHeight, newVersion uint64, status int) {
 	blockchain.Lock()
 	defer blockchain.Unlock()
 
@@ -194,32 +194,83 @@ func (blockchain *Blockchain) IterateDeleteRecord(callback func(record *BlockRec
 			return 0, 0, StatusCorruptBlock
 		}
 
-		// loop through all records in this block
 		refactorBlock := false
+
+		// Decode all file records at once. This is needed due to potential referenced tags.
+		// If a file is deleted or referenced tag data changed, it would corrupt the blockchain if the other records were not updated.
+		filesD, err := decodeBlockRecordFiles(block.RecordsRaw, block.NodeID)
+		if err != nil {
+			return 0, 0, StatusCorruptBlock
+		}
+
+		// loop through all file records in this block
+		var newFileRecords []BlockRecordFile
+
+		if callbackFile == nil {
+			newFileRecords = filesD
+		} else {
+			for n := range filesD {
+				switch callbackFile(&filesD[n]) {
+				case 0: // no action on record
+					newFileRecords = append(newFileRecords, filesD[n])
+
+				case 1: // delete record
+					refactorBlock = true
+					refactorBlockchain = true
+
+				case 2: // replace record
+					newFileRecords = append(newFileRecords, filesD[n])
+					refactorBlock = true
+					refactorBlockchain = true
+
+				case 3: // error blockchain corrupt
+					return 0, 0, StatusCorruptBlockRecord
+				}
+			}
+		}
+
+		// loop through all other (non-file) records in this block
 		var newRecordsRaw []BlockRecordRaw
 
 		for n := range block.RecordsRaw {
-			switch callback(&block.RecordsRaw[n]) {
+			// File and Tag records were already handled in above loop.
-			case 0: // no action on record
+			if block.RecordsRaw[n].Type == RecordTypeFile || block.RecordsRaw[n].Type == RecordTypeTagData {
+				continue
+			}
+
+			if callbackOther == nil {
 				newRecordsRaw = append(newRecordsRaw, block.RecordsRaw[n])
+			} else {
+				switch callbackOther(&block.RecordsRaw[n]) {
+				case 0: // no action on record
+					newRecordsRaw = append(newRecordsRaw, block.RecordsRaw[n])
 
-			case 1: // delete record
+				case 1: // delete record
-				refactorBlock = true
+					refactorBlock = true
-				refactorBlockchain = true
+					refactorBlockchain = true
 
-			case 2: // replace record
+				case 2: // replace record
-				newRecordsRaw = append(newRecordsRaw, block.RecordsRaw[n])
+					newRecordsRaw = append(newRecordsRaw, block.RecordsRaw[n])
-				refactorBlock = true
+					refactorBlock = true
-				refactorBlockchain = true
+					refactorBlockchain = true
 
-			case 3: // error blockchain corrupt
+				case 3: // error blockchain corrupt
-				return 0, 0, StatusCorruptBlockRecord
+					return 0, 0, StatusCorruptBlockRecord
+				}
 			}
 		}
 
 		// If refactor, re-calculate the block. All later blocks need to be re-encoded due to change of previous block hash. The version number needs to change.
 		// Note: Deleting records may leave referenced records orphaned, such as RecordTypeTagData for deleted file records.
 		if refactorBlock {
+			// re-encode the block
+			filesRecords, err := encodeBlockRecordFiles(newFileRecords)
+			if err != nil {
+				return 0, 0, StatusCorruptBlock
+			}
+
+			newRecordsRaw = append(newRecordsRaw, filesRecords...)
+
 			if len(newRecordsRaw) > 0 {
 				blockchainNew = append(blockchainNew, Block{OwnerPublicKey: blockchain.publicKey, RecordsRaw: newRecordsRaw, BlockchainVersion: refactorVersion, Number: uint64(len(blockchainNew))})
 			}

blockchain/File.go

@@ -62,26 +62,17 @@ func (blockchain *Blockchain) FileExists(hash []byte) (files []BlockRecordFile,
 }
 
 // DeleteFiles deletes files from the blockchain. Status is StatusX.
-func (blockchain *Blockchain) DeleteFiles(IDs []uuid.UUID) (newHeight, newVersion uint64, deletedFiles []BlockRecordFile, status int) {
+func (blockchain *Blockchain) DeleteFiles(IDs []uuid.UUID) (newHeight, newVersion uint64, deletedFiles []*BlockRecordFile, status int) {
-	newHeight, newVersion, status = blockchain.IterateDeleteRecord(func(record *BlockRecordRaw) (deleteAction int) {
+	newHeight, newVersion, status = blockchain.IterateDeleteRecord(func(file *BlockRecordFile) (deleteAction int) {
-		if record.Type != RecordTypeFile {
-			return 0 // no action on record
-		}
-
-		filesDecoded, err := decodeBlockRecordFiles([]BlockRecordRaw{*record}, nil)
-		if err != nil || len(filesDecoded) != 1 {
-			return 3 // error blockchain corrupt
-		}
-
 		for _, id := range IDs {
-			if id == filesDecoded[0].ID { // found a file ID to delete?
+			if file.ID == id { // found a file ID to delete?
-				deletedFiles = append(deletedFiles, filesDecoded[0])
+				deletedFiles = append(deletedFiles, file)
 				return 1 // delete record
 			}
 		}
 
 		return 0 // no action on record
-	})
+	}, nil)
 
 	return
 }

blockchain/Profile.go

@@ -74,7 +74,7 @@ func (blockchain *Blockchain) ProfileWrite(fields []BlockRecordProfile) (newHeig
 
 // ProfileDelete deletes fields and blobs from the blockchain. Status is StatusX.
 func (blockchain *Blockchain) ProfileDelete(fields []uint16) (newHeight, newVersion uint64, status int) {
-	return blockchain.IterateDeleteRecord(func(record *BlockRecordRaw) (deleteAction int) {
+	return blockchain.IterateDeleteRecord(nil, func(record *BlockRecordRaw) (deleteAction int) {
 		if record.Type != RecordTypeProfile {
 			return 0 // no action
 		}