feat: add rpc torrentGet.availability (#3252)

docs/rpc-spec.md

@@ -196,6 +196,7 @@ The 'source' column here corresponds to the data structure there.
 |:--|:--|:--
 | `activityDate` | number | tr_stat
 | `addedDate` | number | tr_stat
+| `availability` | array (see below)| tr_torrentAvailability()
 | `bandwidthPriority` | number | tr_priority_t
 | `comment` | string | tr_torrent_view
 | `corruptEver`| number | tr_stat
@@ -270,6 +271,7 @@ The 'source' column here corresponds to the data structure there.
 | `webseeds`| array of strings | tr_tracker_view
 | `webseedsSendingToUs`| number| tr_stat
 
+`availability`: An array of `pieceCount` numbers representing the number of connected peers that have each piece, or -1 if we already have the piece ourselves.
 
 `files`: array of objects, each containing:
 
@@ -969,6 +971,7 @@ Transmission 4.0.0 (`rpc-version-semver` 5.3.0, `rpc-version`: 17)
 | `session-get` | new arg `script-torrent-done-seeding-enabled`
 | `session-get` | new arg `script-torrent-done-seeding-filename`
 | `torrent-add` | new arg `labels`
+| `torrent-get` | new arg `availability`
 | `torrent-get` | new arg `file-count`
 | `torrent-get` | new arg `group`
 | `torrent-get` | new arg `percentComplete`

libtransmission/peer-mgr.cc

@@ -1482,36 +1482,35 @@ void tr_peerMgrOnTorrentGotMetainfo(tr_torrent* tor)
     }
 }
 
-void tr_peerMgrTorrentAvailability(tr_torrent const* tor, int8_t* tab, unsigned int tabCount)
+int8_t tr_peerMgrPieceAvailability(tr_torrent const* tor, tr_piece_index_t piece)
+{
+    if (!tor->hasMetainfo())
+    {
+        return 0;
+    }
+
+    if (tor->isSeed() || tor->hasPiece(piece))
+    {
+        return -1;
+    }
+
+    auto const& peers = tor->swarm->peers;
+    return std::count_if(std::begin(peers), std::end(peers), [piece](auto const* peer) { return peer->have.test(piece); });
+}
+
+void tr_peerMgrTorrentAvailability(tr_torrent const* tor, int8_t* tab, unsigned int n_tabs)
 {
     TR_ASSERT(tr_isTorrent(tor));
     TR_ASSERT(tab != nullptr);
-    TR_ASSERT(tabCount > 0);
+    TR_ASSERT(n_tabs > 0);
 
-    std::fill_n(tab, tabCount, int8_t{});
+    std::fill_n(tab, n_tabs, int8_t{});
 
-    if (tor->hasMetainfo())
+    auto const interval = tor->pieceCount() / static_cast<float>(n_tabs);
+    for (tr_piece_index_t i = 0; i < n_tabs; ++i)
     {
-        auto const& peers = tor->swarm->peers;
-        float const interval = tor->pieceCount() / (float)tabCount;
-        auto const isSeed = tor->isSeed();
-
-        for (tr_piece_index_t i = 0; i < tabCount; ++i)
-        {
-            int const piece = i * interval;
-
-            if (isSeed || tor->hasPiece(piece))
-            {
-                tab[i] = -1;
-            }
-            else
-            {
-                tab[i] = std::count_if(
-                    std::begin(peers),
-                    std::end(peers),
-                    [piece](auto const* peer) { return peer->have.test(piece); });
-            }
-        }
+        auto const piece = static_cast<tr_piece_index_t>(i * interval);
+        tab[i] = tr_peerMgrPieceAvailability(tor, piece);
     }
 }
 

libtransmission/peer-mgr.h

@@ -154,6 +154,9 @@ void tr_peerMgrAddTorrent(tr_peerMgr* manager, struct tr_torrent* tor);
 
 void tr_peerMgrRemoveTorrent(tr_torrent* tor);
 
+// return the number of connected peers that have `piece`, or -1 if we already have it
+int8_t tr_peerMgrPieceAvailability(tr_torrent const* tor, tr_piece_index_t piece);
+
 void tr_peerMgrTorrentAvailability(tr_torrent const* tor, int8_t* tab, unsigned int tabCount);
 
 uint64_t tr_peerMgrGetDesiredAvailable(tr_torrent const* tor);

libtransmission/quark.cc

@@ -18,7 +18,7 @@ using namespace std::literals;
 namespace
 {
 
-auto constexpr my_static = std::array<std::string_view, 391>{ ""sv,
+auto constexpr my_static = std::array<std::string_view, 392>{ ""sv,
                                                               "activeTorrentCount"sv,
                                                               "activity-date"sv,
                                                               "activityDate"sv,
@@ -42,6 +42,7 @@ auto constexpr my_static = std::array<std::string_view, 391>{ ""sv,
                                                               "anti-brute-force-enabled"sv,
                                                               "anti-brute-force-threshold"sv,
                                                               "arguments"sv,
+                                                              "availability"sv,
                                                               "bandwidth-priority"sv,
                                                               "bandwidthPriority"sv,
                                                               "bind-address-ipv4"sv,

libtransmission/quark.h

@@ -45,6 +45,7 @@ enum
     TR_KEY_anti_brute_force_enabled, /* rpc */
     TR_KEY_anti_brute_force_threshold, /* rpc */
     TR_KEY_arguments, /* rpc */
+    TR_KEY_availability, // rpc
     TR_KEY_bandwidth_priority,
     TR_KEY_bandwidthPriority,
     TR_KEY_bind_address_ipv4,

libtransmission/rpcimpl.cc

@@ -25,7 +25,7 @@
 #include "error.h"
 #include "file.h"
 #include "log.h"
-#include "platform-quota.h" /* tr_device_info_get_disk_space() */
+#include "peer-mgr.h"
 #include "quark.h"
 #include "rpcimpl.h"
 #include "session-id.h"
@@ -490,6 +490,14 @@ static void initField(tr_torrent const* const tor, tr_stat const* const st, tr_v
         tr_variantInitInt(initme, st->addedDate);
         break;
 
+    case TR_KEY_availability:
+        tr_variantInitList(initme, tor->pieceCount());
+        for (tr_piece_index_t piece = 0, n = tor->pieceCount(); piece < n; ++piece)
+        {
+            tr_variantListAddInt(initme, tr_peerMgrPieceAvailability(tor, piece));
+        }
+        break;
+
     case TR_KEY_bandwidthPriority:
         tr_variantInitInt(initme, tr_torrentGetPriority(tor));
         break;