libtorrent_flutter 1.7.8

Native libtorrent 2.0 bindings for Flutter with a built-in HTTP streaming server for instant torrent video playback. Supports Windows, Linux, macOS, iOS, and Android.

Changelog

1.7.8

• Revert: Rolled back streaming engine changes from 1.7.6–1.7.7 (wider priority window, prefetch changes, notifySeek API, FIN detection) — reverted to the stable 1.7.4 streaming logic with the 1.7.5 is_ephemeral bug fix
• Kept: Android encryption build (OpenSSL 3.2.1, -Dencryption=ON, -O3 -flto) from 1.7.6

1.7.7

• Seeking: Added notifySeek() API — Dart can now notify the native engine of a seek directly, bypassing HTTP detection entirely. When using players like mpv that buffer heavily (~150 MB demuxer cache), seeks within the cached region never triggered a new HTTP range request, causing 25+ second delays. The engine now responds to seeks within milliseconds regardless of player cache state
• Seeking: Non-blocking FIN/RST detection in the HTTP send loop — uses WSAPoll/poll + MSG_PEEK recv between send iterations to detect when the player closes the connection, enabling faster seek recovery for out-of-cache seeks
• Seeking: On seek, all non-tail piece priorities are reset to dont_download — prevents old-position pieces from competing for bandwidth with the new seek target
• Streaming: Widened priority lookahead from current+2 to current+8 pieces with staggered priorities (first 3 at priority 6, rest at priority 4) and wider deadline spacing — keeps the download pipeline full while concentrating bandwidth on the immediate piece
• Streaming: Expanded disk prefetch from 3 to 5 pieces — more pieces are pre-read from storage while the current piece is being sent, reducing I/O stalls between pieces

1.7.6

• Build (Android): Enabled encryption — libtorrent is now compiled with -Dencryption=ON and statically linked against OpenSSL 3.2.1 cross-compiled for each ABI. Peers can now negotiate encrypted connections (pe_enabled/pe_forced), dramatically improving peer availability and download speeds in swarms that prefer or require encryption
• Build (Android): Cross-compiles OpenSSL 3.2.1 as static libraries (libssl.a, libcrypto.a) for arm64-v8a, armeabi-v7a, and x86_64 — no runtime OpenSSL dependency on the device
• Build (Android): Upgraded compiler optimization from -O2 to -O3 with link-time optimization (-flto) for faster piece hashing, alert processing, and streaming throughput
• Build (Android): Removed -DTORRENT_USE_SSL=0 from the bridge build — encryption settings in C++ (pe_enabled/pe_forced) are no longer silently ignored
• Build (Android): Added -fPIC to OpenSSL cross-compilation for armeabi-v7a — fixes linker error with 32-bit ARM assembly relocations
• Streaming: Reduced memory copies per piece from 3 to 1 — ReadResult now uses shared_ptr<vector<char>> so piece data flows from alert to cache to socket without redundant copies
• Streaming: Widened priority lookahead from current+2 to current+5 pieces — more peers download ahead of playback, reducing stalls on unstable connections
• Streaming: Expanded disk prefetch from 1 to 3 pieces — next 3 downloaded pieces are pre-read from libtorrent storage while the current piece is being sent to the player
• Streaming: Increased socket send buffer from 2 MB to 8 MB — prevents kernel buffer stalls on fast networks

1.7.5

• FIX: Added is_ephemeral check around the metadata_received_alert handler so that only streaming torrents get paused/zeroed after metadata, not regular downloads

1.7.4

• Streaming: Removed sequential_download mode — piece order is now driven entirely by set_piece_deadline, libtorrent's purpose-built time-critical mechanism. Improves seek recovery and swarm efficiency
• Streaming: Added hot piece cache — on_piece_read populates CachePiece buffers in memory, read_piece_data checks cache first. Instant re-reads for player probes, overlapping range requests, and small backward seeks
• Streaming: Trailing retention window — last 3 played pieces are kept alive instead of being immediately set to dont_download. Handles player re-reads and small rewinds without re-downloading
• Streaming: Adaptive bitrate estimation — startup piece count and buffer reporting now scale with file size. A 1.2 GB file gets ~2 critical startup pieces; a 4 GB file gets 1–2 instead of the old fixed 5, dramatically reducing time-to-first-frame for large files
• Streaming: Tail (moov atom) priority lowered from top_priority to priority 5 with 1000 ms deadlines — head startup pieces (priority 7, deadline 0–100 ms) always win the time-critical picker, preventing tail downloads from stealing bandwidth at startup
• Seeking: Trailing retention window is flushed on seek — old played pieces are dropped to dont_download immediately, freeing all bandwidth for the new seek position

1.7.3

• FIX (CRASH): Fixed SIGABRT crash on stream shutdown — cache->close() destroyed TorrReader objects and their mutexes while HTTP client threads were still using them. Reordered shutdown to join all threads before closing the cache
• FIX: Added guard in close_reader() to skip cleanup if the cache is already closed, preventing double-free of reader mutexes
• FIX: read_piece_data() now checks active flag in its wait predicate — threads wake immediately on shutdown instead of blocking for up to 10 seconds
• FIX: lt_destroy_session no longer holds streams_mu while joining threads, preventing deadlock with the alert thread
• HARDENING: All thread entry points (handle_connection, client thread lambda), shutdown paths (lt_stop_stream, lt_destroy_session), and cache cleanup (close_reader, TorrCache::close) wrapped in try-catch — the native library will never crash the app, even on unexpected shutdown races

1.7.2

• FIX (CRASH): Fixed SIGABRT crash (pthread_mutex_destroy called on a destroyed mutex) when stopping a stream — HTTP client handler threads were detached and continued accessing StreamEngine mutexes after the engine was destroyed. Client threads are now tracked, joined, and their sockets force-closed during shutdown
• FIX: Fixed potential double-close of the HTTP listen socket during stream shutdown
• FIX: lt_destroy_session now properly closes listen sockets and joins client threads before destroying stream engines

1.7.1

• Streaming: Replaced TorrServer-style async cache pipeline with lt2http-style direct storage reads — pieces are read straight from libtorrent disk storage instead of going through an intermediate RAM cache, eliminating seek delays
• Streaming: Narrowed priority window from 25-piece gradient (Now/Next/Readahead/High/Normal) to just current piece + 2 ahead — focuses 100% of bandwidth on what the player actually needs
• Streaming: 100% forward cache — everything ahead of playback, nothing behind. A 64 MB cache can now stream a 60 GB file by aggressively evicting played pieces
• FIX: Fixed downloads being killed during gaps between player HTTP requests — clear_priority_impl() was setting ALL pieces to dont_download when no readers existed
• FIX: Protected current reader piece and next piece from cache eviction, preventing evict-download-evict loops at piece boundaries
• FIX: Removed detached threads that spawned clean_pieces() and get_removable_pieces() on every piece write/read — these overrode serve_range priorities and stopped downloads
• Build (Windows): Reduced DLL size from 9.4 MB to 146 KB

1.7.0

• FIX (macOS): Fixed crash on launch — libssl.3.dylib / libcrypto.3.dylib were referenced via hardcoded Homebrew paths (/opt/homebrew/opt/openssl@3/lib/...), which don't exist on end-user machines. The dylib now uses @loader_path/ references and bundles OpenSSL alongside the plugin
• Build (macOS): Added install_name_tool POST_BUILD step in CMakeLists.txt to automatically rewrite OpenSSL load paths during compilation
• Build (macOS): Added build_macos.sh — one-command script that builds the dylib, copies OpenSSL from Homebrew, fixes all dylib cross-references, and places files in macos/ and prebuilt/macos/universal/
• Packaging (macOS): Updated podspec to vendor libssl.3.dylib and libcrypto.3.dylib alongside the main plugin dylib
• Streaming: Improved seek performance — 5 deadline pieces at deadline=0, unlimited unchoke slots, optimized cancel_non_critical() timing
• Engine: unchoke_slots_limit changed from 4 to unlimited (-1) — fixes issue where only 4 peers would upload despite hundreds connected

1.6.9

• Engine: Complete rewrite of the C++ streaming engine — new priority system, HTTP server, and piece management
• Streaming: 5-level priority gradient (NOW=7, NEXT=6, READAHEAD=5, BACK=1, SKIP=0) — only downloads the playback window and head/tail metadata, not the entire file
• Streaming: set_piece_deadline() for time-critical downloads — pieces requested from multiple peers simultaneously, slow requests auto-cancelled
• Streaming: Adaptive readahead window (3–50 pieces) grows with smooth playback, resets on seek
• Streaming: 8-piece backward buffer keeps recently-played pieces available for quick rewinds
• Streaming: Configurable RAM piece cache via maxCacheBytes — from 128MB for smart TVs to 2GB for desktops. Sliding window eviction with safe-zone protection around the playhead
• Seeking: Threaded HTTP connection handler — new connections preempt old ones instantly via socket close, no more blocking the accept loop
• Seeking: clear_piece_deadlines() on seek — immediately stops downloading for old position and redirects bandwidth to new target
• Seeking: Aggressive seek deadlines (6 pieces at 200ms spacing) at the new position
• Seeking: seek_generation counter aborts blocked piece waits within milliseconds
• Performance: Condition-variable-based piece waiting — zero CPU polling
• Performance: Alert-driven piece tracking via piece_finished_alert — no status polling for piece availability
• Performance: Piece data cache with safe-zone (5 pieces around playhead never evicted), smart trim on seek preserves nearby cached data
• Tuning: max_failcount=3 — peers survive seek transitions instead of being dropped
• Tuning: peer_turnover 5% every 30s — faster replacement of slow peers
• Tuning: Connection flood on startup (connection_speed=200, torrent_connect_boost=200) for fast peer acquisition
• API: startStream() now accepts maxCacheBytes to control RAM usage (0 = default ~128MB)
• API: Backward-compatible bufferPct getter on StreamInfo
• API: New StreamState enum (idle, buffering, ready, seeking, error) and streamState field on StreamInfo
• API: New fields on StreamInfo: bufferSeconds, bufferPieces, readaheadWindow, activePeers, downloadRate
• Compat: All existing API methods preserved — addMagnet(), startStream(), stopStream(), disposeTorrent(), etc. work unchanged

1.6.8

• iOS: Built XCFramework with both device (arm64-iphoneos) and simulator (arm64+x86_64-iphonesimulator) slices — iOS Simulator now works on Apple Silicon and Intel Macs
• iOS: Replaced fat .a binary with .xcframework — Apple's recommended approach for multi-platform static libraries
• iOS: Updated podspec to use vendored_frameworks with SDK-conditional -force_load linker flags
• CI: Build workflow now compiles libtorrent + torrent_bridge for three iOS targets (arm64 device, arm64 simulator, x86_64 simulator) and packages them via xcodebuild -create-xcframework
• Publish: Dropped Android x86_64 prebuilt from pub package to stay under 100 MB limit

1.6.6

IOS fixes

1.6.6

• FIX (iOS): Added SystemConfiguration framework dependency to podspec — resolves Undefined symbol: _SCNetworkReachabilityCreateWithAddress linker errors when building for iOS release

1.6.5

• CRITICAL FIX: Concurrent connections (head + tail) were killing each other — every new HTTP connection overwrote a global request ID, instantly aborting the other. Players that open two connections (VLC, mpv, ExoPlayer) would loop endlessly until enough pieces were cached. Replaced with a seek-generation counter that only aborts stale connections on actual seeks
• FIX: Tail/metadata range requests no longer hijack read_head — the priority loop stays focused on the playback position instead of jumping to the end of the file
• Streaming: LRU piece cache (48 entries) — avoids repeated disk reads for recently served pieces
• Streaming: Head + tail preload on stream start — first 5 pieces get staggered deadlines, last ~512KB is pre-fetched for container metadata (MKV cues, MP4 moov)
• Streaming: Dynamic readahead window (8–40 pieces) scales with download speed, targeting ~15s of buffer
• Streaming: Wider inline lookahead (6 pieces) with staggered deadlines during serve
• Seeking: Cache invalidation on seek — evicts stale pieces, preserves tail pieces
• Seeking: Wider post-seek focus (5 queued pieces instead of 2)
• Engine: Fixed suggest_mode — was set as bool instead of the correct enum value
• Engine: Fixed torrent_connect_boost exceeding documented max (255)
• Engine: mixed_mode_algorithm set to peer_proportional — stops starving uTP peers behind NAT
• Engine: Added DHT bootstrap nodes, piece_extent_affinity, auto_sequential
• Engine: Tuned send buffer watermarks, peer turnover, socket buffer sizes
• Serve: DLNA headers for smart TV compatibility
• Serve: CORS OPTIONS preflight support
• Serve: 2MB send buffer, 1MB send chunks
• Serve: Case-insensitive HTTP Range header parsing
• Serve: Adaptive priority loop interval (100ms buffering, 250ms steady)

1.6.4

• CRITICAL FIX: HTTP server sent Connection: keep-alive but closed the socket after every request — VLC trusted the keep-alive promise, tried to reuse the dead connection, got a broken pipe, and rendered a black screen. Fixed by switching to Connection: close, which correctly tells the player to open a new TCP connection for each range request. This is the standard model used by other torrent streaming servers.
• Serve: HEAD requests now return headers and close cleanly without falling through to the data-serving path
• Serve: Removed redundant while loop around single-use connection handling — the code now clearly reflects the one-request-per-connection model

1.6.3

• Streaming: Instant start — staggered piece deadlines (0ms, 500ms, 1000ms…) on startup instead of flat 0ms for all. libtorrent's time-critical picker now funnels all bandwidth to piece 0 first, so playback can begin as soon as 1 piece arrives instead of waiting for 8
• Streaming: Shrunk critical window from 6 pieces → 2, hot window from 9 → 5, readahead from 15 → 6 — concentrates bandwidth on the most urgent data per libtorrent's streaming docs: "any block you request that is not urgent takes away bandwidth from urgent pieces"
• Streaming: Buffer percentage now based on the 2-piece critical window — reports "ready" faster since it no longer waits for 6 pieces
• Seeking: Tighter seek focus — 2 pieces at staggered near-zero deadlines + 2 more at 200ms stagger (was 4 all at 0ms), reducing bandwidth dilution on seek
• Seeking: Seek cooldown reduced from 1000ms → 100ms — priority loop resumes almost immediately after a seek instead of staying blind for a full second
• Seeking: Wait timeout reduced from 120s → 30s — fails faster on dead peers instead of hanging
• Performance: Priority loop now runs every 100ms (was 200ms) for faster reaction to playback position changes
• Performance: libtorrent tick_interval set to 100ms (was 500ms default) — internal scheduler reacts 5x faster to deadline changes and priority updates
• Serve: Inline lookahead reduced from 5 → 3 pieces with 100ms stagger (was 10ms) — less bandwidth competition with the current piece

1.6.2

• CRITICAL FIX: Removed force_recheck() from cache eviction — it was re-hashing the ENTIRE torrent, marking ALL pieces (including currently streaming ones) as unknown, killing the stream
• Streaming: Capped readahead window to 50% of cache capacity — prevents downloading so far ahead that the cache overflows and evicts data at the current playback position
• Streaming: Hard safety floor — cache eviction NEVER evicts anything within 5 pieces of the current playhead, regardless of cache pressure

1.6.1

• Streaming: Fixed serial pipeline stall after seek — serve_range now pre-primes the next 5 pieces with priority 7 and staggered deadlines before each wait_for_piece call, so the swarm downloads them in parallel instead of one at a time
• Streaming: Reduced seek cooldown from 3s → 1s — the new serve_range lookahead covers the gap, so the priority loop can resume sooner and set broader readahead windows

1.6.0

• Streaming: Rewrote priority system using torrest-cpp's proven priority-only-upgrade pattern — never downgrade piece priorities, staggered i*10ms deadlines for the hot window
• Streaming: Increased critical window from 3 → 5 pieces at deadline=0ms for faster initial playback
• Streaming: Total seek focus — on seek, all piece priorities are wiped and ONLY the seek position + 3 pieces get deadline=0ms with a 3-second cooldown before the priority loop resumes
• Streaming: wait_for_piece timeout increased from 15s → 120s to prevent "Stream ends prematurely" errors during slow torrent startup
• Streaming: Reduced readahead buffer from 30 → 15 pieces to concentrate bandwidth closer to the playhead
• Engine: Added no_recheck_incomplete_resume — skips file recheck on resume for faster startup
• Engine: Added allow_multiple_connections_per_ip — connects to seedboxes, VPNs, and shared NAT peers
• Engine: Added peer_connect_timeout=3s for faster peer handshakes
• Engine: Tuned timeouts to stop peer churn (piece_timeout 2→5s, request_timeout 2→4s, peer_timeout 5→10s) — proven by libtorrent issue #7666, torrest, and Elementum
• Engine: whole_pieces_threshold increased 5 → 20, forcing fast peers to complete whole pieces instead of scattering blocks

1.5.0

• Streaming: Removed speculative tail preloading — the engine no longer downloads the last 4MB of a file at startup. Modern players (MPV, VLC, etc.) fetch container metadata (MP4 moov atom, MKV cues) on-demand via HTTP range requests, which the built-in server already supports
• Streaming: Head-only preload now sets 8 pieces at flat deadline=0ms instead of staggered 30ms intervals, focusing 100% of startup bandwidth on the beginning of the file
• Streaming: Removed file anchor logic from the priority loop that re-prioritized the last 2 pieces every 200ms, which competed with the playhead for bandwidth
• Performance: Startup time reduced from ~30–60s to ~5–15s by eliminating bandwidth competition between head and tail piece downloads

1.4.0

• Platform: Added iOS support

1.3.0

• Platform: Added iOS support (arm64 device + x86_64 simulator, universal static library)
• CI: New build-ios job cross-compiles libtorrent + torrent_bridge as a static .a for iOS, merged with lipo
• Packaging: iOS podspec with -force_load so all FFI symbols are visible via DynamicLibrary.process()

1.2.0

• License: Switched to GPL v3 (OSI-approved)
• Streaming: Dual-end preloading — fetches first 4MB and last 4MB of the file simultaneously on stream start. The tail contains the MP4/MKV moov atom (seek table), enabling instant seeking without buffering the whole file first
• Streaming: Staggered 30ms piece deadlines on the head (down from 45ms) for faster playback start
• API: disposeTorrent(id) — stop streams, remove torrent, and delete files in one call
• API: disposeAll() — clean up every torrent and stream at once (ideal for exit button)
• API: startStream() now accepts maxCacheBytes for a sliding window RAM cache limit
• API: init() now accepts defaultSavePath (defaults to system temp dir — no permission setup needed)
• API: addMagnet() and addTorrentFile() savePath is now optional (uses defaultSavePath)
• README: Fully rewritten with complete API documentation and code examples

1.1.0

• Streaming: Removed sequential_download flag (conflicts with set_piece_deadline)
• Streaming: Reduced readahead from 150 to 30 pieces to avoid excessive pre-buffering
• Streaming: clear_piece_deadlines() on seek + 1-second cooldown for faster seek response
• Streaming: Re-enabled uTP for incoming and outgoing connections (reaches more peers behind NAT)
• Cache: Configurable RAM cache limit with percentage-based sliding window eviction (10% safety buffer, min 5 pieces)
• Save path: Defaults to system temp directory on all platforms
• CI: Automatic GitHub Release creation with zipped native libraries on every build
• pubspec: Added repository, issue_tracker, and topics fields for pub.dev discoverability

1.0.0

• Initial release
• Native libtorrent 2.0 bindings via Dart FFI
• Built-in HTTP streaming server with byte-range support
• Windows, Linux, macOS, and Android support with prebuilt binaries (no build required)
• Auto-fetches best public trackers on startup
• Magnet link and .torrent file support
• Per-file streaming with automatic largest-file selection
• torrentUpdates and streamUpdates streams for reactive UI
• DHT, PEX, LSD peer discovery