Struct BtMessageHandler 

pub struct BtMessageHandler;

BT Message Handler for block-level operations

Manages the process of requesting and receiving individual blocks from peers during piece download.

Implementations

impl BtMessageHandler

pub async fn request_block( connections: &mut [BtPeerConn], piece_index: u32, block_offset: u32, block_length: u32, ) -> Result<BlockDownloadResult>

Request and receive a single block from available peers

This method implements the core block request/receive loop:

1. Send the block request to a peer
2. Wait for the response with timeout
3. Handle various message types while waiting
4. Return the block data on success

Arguments

• connections - Mutable slice of active peer connections
• piece_index - The index of the piece this block belongs to
• block_offset - The byte offset within the piece
• block_length - The length of this block in bytes

Returns

• Ok(BlockDownloadResult) - Result containing success status and data
• Err(Aria2Error) - If all peers fail to respond

pub async fn download_piece_blocks( connections: &mut [BtPeerConn], piece_index: u32, piece_length: u32, num_blocks: u32, ) -> Result<Vec<u8>>

Download all blocks for a piece with retry logic

Coordinates the download of all blocks that make up a piece, implementing retry logic for failed pieces.

Arguments

• connections - Mutable slice of active peer connections
• piece_index - Index of the piece to download
• piece_length - Total length of this piece in bytes
• num_blocks - Number of blocks in this piece

Returns

• Ok(Vec<u8>) - Complete piece data if all blocks downloaded successfully
• Err(Aria2Error) - If piece download fails after all retries

pub async fn download_piece_blocks_endgame( connections: &mut [BtPeerConn], piece_index: u32, piece_length: u32, num_blocks: u32, endgame_state: &mut EndgameState, ) -> Result<Vec<u8>>

Download all blocks for a piece using endgame mode (duplicate request strategy).

In endgame mode, when few pieces remain, we request each block from ALL available peers simultaneously. When any peer responds first, we immediately send Cancel messages to the other peers to stop them from sending redundant data.

Phase 14 - B1/B2: Endgame Duplicate Request Strategy + Cancel on Block Arrival

Arguments

• connections - Mutable slice of active peer connections
• piece_index - Index of the piece to download
• piece_length - Total length of this piece in bytes
• num_blocks - Number of blocks in this piece
• endgame_state - Mutable reference to EndgameState for tracking duplicate requests

Returns

• Ok(Vec<u8>) - Complete piece data if all blocks downloaded successfully
• Err(Aria2Error) - If piece download fails after all retries