docs: [torrust#260] crate docs for shared mod

cSpell.json

@@ -37,6 +37,7 @@
         "leechers",
         "libtorrent",
         "Lphant",
+        "metainfo",
         "middlewares",
         "mockall",
         "multimap",

docs/media/mandelbrot_2048x2048_infohash_v1.png.torrent.json

@@ -0,0 +1,10 @@
+{
+    "created by": "qBittorrent v4.4.1",
+    "creation date": 1679674628,
+    "info": {
+        "length": 172204,
+        "name": "mandelbrot_2048x2048.png",
+        "piece length": 16384,
+        "pieces": "<hex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hex>"
+    }
+}

src/shared/bit_torrent/common.rs

@@ -1,27 +1,56 @@
+//! `BitTorrent` protocol primitive types
+//!
+//! [BEP 3. The `BitTorrent` Protocol Specification](https://www.bittorrent.org/beps/bep_0003.html)
 use aquatic_udp_protocol::{AnnounceEvent, NumberOfBytes};
 use serde::{Deserialize, Serialize};
 
+/// The maximum number of torrents that can be returned in an `scrape` response.
+/// It's also the maximum number of peers returned in an `announce` response.
+///
+/// The [BEP 15. UDP Tracker Protocol for `BitTorrent`](https://www.bittorrent.org/beps/bep_0015.html)
+/// defines this limit:
+///
+/// "Up to about 74 torrents can be scraped at once. A full scrape can't be done
+/// with this protocol."
+///
+/// The [BEP 48. Tracker Protocol Extension: Scrape](https://www.bittorrent.org/beps/bep_0048.html)
+/// does not specifically mention this limit, but the limit is being used for
+/// both the UDP and HTTP trackers since it's applied at the domain level.
 pub const MAX_SCRAPE_TORRENTS: u8 = 74;
+
+/// HTTP tracker authentication key length.
+///
+/// See function to [`generate`](crate::tracker::auth::generate) the
+/// [`ExpiringKeys`](crate::tracker::auth::ExpiringKey) for more information.
 pub const AUTH_KEY_LENGTH: usize = 32;
 
 #[repr(u32)]
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
-pub enum Actions {
+enum Actions {
+    // todo: it seems this enum is not used anywhere. Values match the ones in
+    // aquatic_udp_protocol::request::Request::from_bytes.
     Connect = 0,
     Announce = 1,
     Scrape = 2,
     Error = 3,
 }
 
+/// Announce events. Described on  the
+/// [BEP 3. The `BitTorrent` Protocol Specification](https://www.bittorrent.org/beps/bep_0003.html)
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "AnnounceEvent")]
 pub enum AnnounceEventDef {
+    /// The peer has started downloading the torrent.
     Started,
+    /// The peer has ceased downloading the torrent.
     Stopped,
+    /// The peer has completed downloading the torrent.
     Completed,
+    /// This is one of the announcements done at regular intervals.
     None,
 }
 
+/// Number of bytes downloaded, uploaded or pending to download (left) by the peer.
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "NumberOfBytes")]
 pub struct NumberOfBytesDef(pub i64);

src/shared/bit_torrent/info_hash.rs

@@ -1,13 +1,147 @@
+//! A `BitTorrent` `InfoHash`. It's a unique identifier for a `BitTorrent` torrent.
+//!
+//! "The 20-byte sha1 hash of the bencoded form of the info value
+//! from the metainfo file."
+//!
+//! See [BEP 3. The `BitTorrent` Protocol Specification](https://www.bittorrent.org/beps/bep_0003.html)
+//! for the official specification.
+//!
+//! This modules provides a type that can be used to represent infohashes.
+//!
+//! > **NOTICE**: It only supports Info Hash v1.
+//!
+//! Typically infohashes are represented as hex strings, but internally they are
+//! a 20-byte array.
+//!
+//! # Calculating the info-hash of a torrent file
+//!
+//! A sample torrent:
+//!
+//! - Torrent file: `mandelbrot_2048x2048_infohash_v1.png.torrent`
+//! - File: `mandelbrot_2048x2048.png`
+//! - Info Hash v1: `5452869be36f9f3350ccee6b4544e7e76caaadab`
+//! - Sha1 hash of the info dictionary: `5452869BE36F9F3350CCEE6B4544E7E76CAAADAB`
+//!
+//! A torrent file is a binary file encoded with [Bencode encoding](https://en.wikipedia.org/wiki/Bencode):
+//!
+//! ```text
+//! 0000000: 6431 303a 6372 6561 7465 6420 6279 3138  d10:created by18
+//! 0000010: 3a71 4269 7474 6f72 7265 6e74 2076 342e  :qBittorrent v4.
+//! 0000020: 342e 3131 333a 6372 6561 7469 6f6e 2064  4.113:creation d
+//! 0000030: 6174 6569 3136 3739 3637 3436 3238 6534  atei1679674628e4
+//! 0000040: 3a69 6e66 6f64 363a 6c65 6e67 7468 6931  :infod6:lengthi1
+//! 0000050: 3732 3230 3465 343a 6e61 6d65 3234 3a6d  72204e4:name24:m
+//! 0000060: 616e 6465 6c62 726f 745f 3230 3438 7832  andelbrot_2048x2
+//! 0000070: 3034 382e 706e 6731 323a 7069 6563 6520  048.png12:piece
+//! 0000080: 6c65 6e67 7468 6931 3633 3834 6536 3a70  lengthi16384e6:p
+//! 0000090: 6965 6365 7332 3230 3a7d 9171 0d9d 4dba  ieces220:}.q..M.
+//! 00000a0: 889b 5420 54d5 2672 8d5a 863f e121 df77  ..T T.&r.Z.?.!.w
+//! 00000b0: c7f7 bb6c 7796 2166 2538 c5d9 cdab 8b08  ...lw.!f%8......
+//! 00000c0: ef8c 249b b2f5 c4cd 2adf 0bc0 0cf0 addf  ..$.....*.......
+//! 00000d0: 7290 e5b6 414c 236c 479b 8e9f 46aa 0c0d  r...AL#lG...F...
+//! 00000e0: 8ed1 97ff ee68 8b5f 34a3 87d7 71c5 a6f9  .....h._4...q...
+//! 00000f0: 8e2e a631 7cbd f0f9 e223 f9cc 80af 5400  ...1|....#....T.
+//! 0000100: 04f9 8569 1c77 89c1 764e d6aa bf61 a6c2  ...i.w..vN...a..
+//! 0000110: 8099 abb6 5f60 2f40 a825 be32 a33d 9d07  ...._`/@.%.2.=..
+//! 0000120: 0c79 6898 d49d 6349 af20 5866 266f 986b  .yh...cI. Xf&o.k
+//! 0000130: 6d32 34cd 7d08 155e 1ad0 0009 57ab 303b  m24.}..^....W.0;
+//! 0000140: 2060 c1dc 1287 d6f3 e745 4f70 6709 3631   `.......EOpg.61
+//! 0000150: 55f2 20f6 6ca5 156f 2c89 9569 1653 817d  U. .l..o,..i.S.}
+//! 0000160: 31f1 b6bd 3742 cc11 0bb2 fc2b 49a5 85b6  1...7B.....+I...
+//! 0000170: fc76 7444 9365 65                        .vtD.ee
+//! ```
+//!
+//! You can generate that output with the command:
+//!
+//! ```text
+//! xxd mandelbrot_2048x2048_infohash_v1.png.torrent
+//! ```
+//!
+//! And you can show only the bytes (hexadecimal):
+//!
+//! ```text
+//! 6431303a6372656174656420627931383a71426974746f7272656e742076
+//! 342e342e3131333a6372656174696f6e2064617465693136373936373436
+//! 323865343a696e666f64363a6c656e6774686931373232303465343a6e61
+//! 6d6532343a6d616e64656c62726f745f3230343878323034382e706e6731
+//! 323a7069656365206c656e67746869313633383465363a70696563657332
+//! 32303a7d91710d9d4dba889b542054d526728d5a863fe121df77c7f7bb6c
+//! 779621662538c5d9cdab8b08ef8c249bb2f5c4cd2adf0bc00cf0addf7290
+//! e5b6414c236c479b8e9f46aa0c0d8ed197ffee688b5f34a387d771c5a6f9
+//! 8e2ea6317cbdf0f9e223f9cc80af540004f985691c7789c1764ed6aabf61
+//! a6c28099abb65f602f40a825be32a33d9d070c796898d49d6349af205866
+//! 266f986b6d3234cd7d08155e1ad0000957ab303b2060c1dc1287d6f3e745
+//! 4f706709363155f220f66ca5156f2c8995691653817d31f1b6bd3742cc11
+//! 0bb2fc2b49a585b6fc767444936565
+//! ```
+//!
+//! You can generate that output with the command:
+//!
+//! ```text
+//! `xxd -ps mandelbrot_2048x2048_infohash_v1.png.torrent`.
+//! ```
+//!
+//! The same data can be represented in a JSON format:
+//!
+//! ```json
+//! {
+//!     "created by": "qBittorrent v4.4.1",
+//!     "creation date": 1679674628,
+//!     "info": {
+//!         "length": 172204,
+//!         "name": "mandelbrot_2048x2048.png",
+//!         "piece length": 16384,
+//!         "pieces": "<hex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hex>"
+//!     }
+//! }
+//! ```
+//!
+//! The JSON object was generated with: <https://github.com/Chocobo1/bencode_online>
+//!
+//! As you can see, there is a `info` attribute:
+//!
+//! ```json
+//! {
+//!     "length": 172204,
+//!     "name": "mandelbrot_2048x2048.png",
+//!     "piece length": 16384,
+//!     "pieces": "<hex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hex>"
+//!  }
+//! ```
+//!
+//! The infohash is the [SHA1](https://en.wikipedia.org/wiki/SHA-1) hash
+//! of the `info` attribute. That is, the SHA1 hash of:
+//!
+//! ```text
+//! 64363a6c656e6774686931373232303465343a6e61
+//! d6532343a6d616e64656c62726f745f3230343878323034382e706e6731
+//! 23a7069656365206c656e67746869313633383465363a70696563657332
+//! 2303a7d91710d9d4dba889b542054d526728d5a863fe121df77c7f7bb6c
+//! 79621662538c5d9cdab8b08ef8c249bb2f5c4cd2adf0bc00cf0addf7290
+//! 5b6414c236c479b8e9f46aa0c0d8ed197ffee688b5f34a387d771c5a6f9
+//! e2ea6317cbdf0f9e223f9cc80af540004f985691c7789c1764ed6aabf61
+//! 6c28099abb65f602f40a825be32a33d9d070c796898d49d6349af205866
+//! 66f986b6d3234cd7d08155e1ad0000957ab303b2060c1dc1287d6f3e745
+//! f706709363155f220f66ca5156f2c8995691653817d31f1b6bd3742cc11
+//! bb2fc2b49a585b6fc7674449365
+//! ```
+//!
+//! You can hash that byte string with <https://www.pelock.com/products/hash-calculator>
+//!
+//! The result is a 20-char string: `5452869BE36F9F3350CCEE6B4544E7E76CAAADAB`
 use std::panic::Location;
 
 use thiserror::Error;
 
+/// `BitTorrent` Info Hash v1
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub struct InfoHash(pub [u8; 20]);
 
 const INFO_HASH_BYTES_LEN: usize = 20;
 
 impl InfoHash {
+    /// Create a new `InfoHash` from a byte slice.
+    ///
     /// # Panics
     ///
     /// Will panic if byte slice does not contains the exact amount of bytes need for the `InfoHash`.
@@ -19,12 +153,13 @@ impl InfoHash {
         ret
     }
 
-    /// For readability, when accessing the bytes array
+    /// Returns the `InfoHash` internal byte array.
     #[must_use]
     pub fn bytes(&self) -> [u8; 20] {
         self.0
     }
 
+    /// Returns the `InfoHash` as a hex string.
     #[must_use]
     pub fn to_hex_string(&self) -> String {
         self.to_string()
@@ -79,13 +214,16 @@ impl std::convert::From<[u8; 20]> for InfoHash {
     }
 }
 
+/// Errors that can occur when converting from a `Vec<u8>` to an `InfoHash`.
 #[derive(Error, Debug)]
 pub enum ConversionError {
+    /// Not enough bytes for infohash. An infohash is 20 bytes.
     #[error("not enough bytes for infohash: {message} {location}")]
     NotEnoughBytes {
         location: &'static Location<'static>,
         message: String,
     },
+    /// Too many bytes for infohash. An infohash is 20 bytes.
     #[error("too many bytes for infohash: {message} {location}")]
     TooManyBytes {
         location: &'static Location<'static>,

src/shared/bit_torrent/mod.rs

@@ -1,2 +1,3 @@
+//! Common code for the `BitTorrent` protocol.
 pub mod common;
 pub mod info_hash;