feat: sequential download in settings.json torrent-add and sesssion-* RPC methods (#7047)

* feat: init sequential download setting from ctor

* feat: `sequantialDownload` arg in `torrent-add` RPC method

* feat: sequential download settings in settings.json

* feat: sequential download arguments in `session-*` RPC methods

* test: fix

docs/Editing-Configuration-Files.md

@@ -103,6 +103,7 @@ Here is a sample of the three basic types: respectively Boolean, Number and Stri
  * **peer-limit-per-torrent:** Number (default = 50)
  * **peer-socket-tos:** String (default = "le") Set the [DiffServ](https://en.wikipedia.org/wiki/Differentiated_services) parameter for outgoing packets. Allowed values are lowercase DSCP names. See the `tr_tos_t` class from `libtransmission/net.h` for the exact list of possible values.
  * **reqq:** Number (default = 2000) The number of outstanding block requests a peer is allowed to queue in the client. The higher this number, the higher the max possible upload speed towards each peer.
+ * **sequentialDownload** Boolean (default = false) Enable sequential download by default when adding torrents.
 
 #### Peer Port
  * **peer-port:** Number (default = 51413)

docs/rpc-spec.md

@@ -469,6 +469,7 @@ Request arguments:
 | `priority-high`      | array     | indices of high-priority file(s)
 | `priority-low`       | array     | indices of low-priority file(s)
 | `priority-normal`    | array     | indices of normal-priority file(s)
+| `sequentialDownload` | boolean   | download torrent pieces sequentially
 
 Either `filename` **or** `metainfo` **must** be included. All other arguments are optional.
 
@@ -572,6 +573,7 @@ Response arguments: `path`, `name`, and `id`, holding the torrent ID integer
 | `seed-queue-size` | number | max number of torrents to uploaded at once (see seed-queue-enabled)
 | `seedRatioLimit` | double | the default seed ratio for torrents to use
 | `seedRatioLimited` | boolean | true if seedRatioLimit is honored by default
+| `sequentialDownload` | boolean | true means sequential download is enabled by default for added torrents
 | `session-id` | string | the current `X-Transmission-Session-Id` value
 | `speed-limit-down-enabled` | boolean | true means enabled
 | `speed-limit-down` | number | max global download speed (KBps)
@@ -1027,6 +1029,9 @@ Transmission 4.0.0 (`rpc-version-semver` 5.3.0, `rpc-version`: 17)
 Transmission 4.1.0 (`rpc-version-semver` 5.4.0, `rpc-version`: 18)
 | Method | Description
 |:---|:---
+| `session-get` | new arg `sequentialDownload`
+| `session-set` | new arg `sequentialDownload`
+| `torrent-add` | new arg `sequentialDownload`
 | `torrent-get` | new arg `sequentialDownload`
 | `torrent-set` | new arg `sequentialDownload`
 | `torrent-get` | new arg `files.beginPiece`

libtransmission/resume.cc

@@ -831,6 +831,15 @@ auto set_from_ctor(
         }
     }
 
+    if ((fields & tr_resume::SequentialDownload) != 0)
+    {
+        if (auto const& val = ctor.sequential_download(mode); val)
+        {
+            tor->set_sequential_download(*val);
+            ret |= tr_resume::SequentialDownload;
+        }
+    }
+
     return ret;
 }
 

libtransmission/rpcimpl.cc

@@ -1452,6 +1452,11 @@ char const* torrentAdd(tr_session* session, tr_variant::Map const& args_in, tr_r
         ctor.set_labels(std::move(labels));
     }
 
+    if (auto const val = args_in.value_if<bool>(TR_KEY_sequentialDownload); val)
+    {
+        ctor.set_sequential_download(TR_FORCE, *val);
+    }
+
     tr_logAddTrace(fmt::format("torrentAdd: filename is '{}'", filename));
 
     if (isCurlURL(filename))
@@ -1839,6 +1844,11 @@ char const* sessionSet(tr_session* session, tr_variant::Map const& args_in, tr_v
         tr_sessionSetAntiBruteForceEnabled(session, *val);
     }
 
+    if (auto const val = args_in.value_if<bool>(TR_KEY_sequentialDownload); val)
+    {
+        session->set_sequential_download(*val);
+    }
+
     session->rpcNotify(TR_RPC_SESSION_CHANGED, nullptr);
 
     return nullptr;
@@ -1974,6 +1984,7 @@ char const* sessionStats(tr_session* session, tr_variant::Map const& /*args_in*/
     case TR_KEY_seedRatioLimited: return session.isRatioLimited();
     case TR_KEY_seed_queue_enabled: return session.queueEnabled(TR_UP);
     case TR_KEY_seed_queue_size: return session.queueSize(TR_UP);
+    case TR_KEY_sequentialDownload: return session.sequential_download();
     case TR_KEY_session_id: return session.sessionId();
     case TR_KEY_speed_limit_down: return session.speed_limit(TR_DOWN).count(Speed::Units::KByps);
     case TR_KEY_speed_limit_down_enabled: return session.is_speed_limited(TR_DOWN);

libtransmission/session.h

@@ -403,6 +403,7 @@ public:
         bool script_torrent_done_enabled = false;
         bool script_torrent_done_seeding_enabled = false;
         bool seed_queue_enabled = false;
+        bool sequential_download = false;
         bool should_delete_source_torrents = false;
         bool should_scrape_paused_torrents = true;
         bool should_start_added_torrents = true;
@@ -495,6 +496,7 @@ public:
                 { TR_KEY_script_torrent_done_seeding_filename, &script_torrent_done_seeding_filename },
                 { TR_KEY_seed_queue_enabled, &seed_queue_enabled },
                 { TR_KEY_seed_queue_size, &seed_queue_size },
+                { TR_KEY_sequentialDownload, &sequential_download },
                 { TR_KEY_sleep_per_seconds_during_verify, &sleep_per_seconds_during_verify },
                 { TR_KEY_speed_limit_down, &speed_limit_down },
                 { TR_KEY_speed_limit_down_enabled, &speed_limit_down_enabled },
@@ -734,6 +736,16 @@ public:
         settings_.reqq = reqq;
     }
 
+    [[nodiscard]] constexpr auto sequential_download() const noexcept
+    {
+        return settings().sequential_download;
+    }
+
+    void set_sequential_download(bool seq) noexcept
+    {
+        settings_.sequential_download = seq;
+    }
+
     // bandwidth
 
     [[nodiscard]] tr_bandwidth& getBandwidthGroup(std::string_view name);

libtransmission/torrent-ctor.h

@@ -150,6 +150,7 @@ public:
     {
         return labels_;
     }
+
     void set_labels(tr_torrent::labels_t&& labels)
     {
         labels_ = std::move(labels);
@@ -205,10 +206,23 @@ public:
         verify_done_callback_ = std::move(callback);
     }
 
+    // ---
+
+    [[nodiscard]] constexpr auto const& sequential_download(tr_ctorMode const mode) const noexcept
+    {
+        return optional_args_[mode].sequential_download_;
+    }
+
+    constexpr void set_sequential_download(tr_ctorMode const mode, bool const seq) noexcept
+    {
+        optional_args_[mode].sequential_download_ = seq;
+    }
+
 private:
     struct OptionalArgs
     {
         std::optional<bool> paused_;
+        std::optional<bool> sequential_download_;
         std::optional<uint16_t> peer_limit_;
         std::string download_dir_;
     };

libtransmission/torrent.cc

@@ -922,7 +922,9 @@ void tr_torrent::init(tr_ctor const& ctor)
 
     mark_changed();
 
-    date_added_ = now_sec; // this is a default that will be overwritten by the resume file
+    // these are defaults that will be overwritten by the resume file
+    date_added_ = now_sec;
+    set_sequential_download(session->sequential_download());
 
     tr_resume::fields_t loaded = {};
 

tests/libtransmission/rpc-test.cc

@@ -223,6 +223,7 @@ TEST_F(RpcTest, sessionGet)
         TR_KEY_seed_queue_size,
         TR_KEY_seedRatioLimit,
         TR_KEY_seedRatioLimited,
+        TR_KEY_sequentialDownload,
         TR_KEY_session_id,
         TR_KEY_speed_limit_down,
         TR_KEY_speed_limit_down_enabled,