Add new webUI API. Closes #6457.

Now getting piece information for a specific torrent is possible via:

* Returns an array of states (integers) of pieces in order. Defined as:
  "0=not downloaded", "1=downloading", "2=downloaded".
  GET /query/getPieceStates/<torrent_hash>

* Returns an array of hashes (strings) of pieces in order:
  GET /query/getPieceHashes/<torrent_hash>

src/base/bittorrent/torrentinfo.cpp

@@ -246,6 +246,21 @@ QVector<int> TorrentInfo::fileIndicesForPiece(int pieceIndex) const
     return res;
 }
 
+QVector<QByteArray> TorrentInfo::pieceHashes() const
+{
+    if (!isValid())
+        return {};
+
+    const int count = piecesCount();
+    QVector<QByteArray> hashes;
+    hashes.reserve(count);
+
+    for (int i = 0; i < count; ++i)
+        hashes += { m_nativeInfo->hash_for_piece_ptr(i), libtorrent::sha1_hash::size };
+
+    return hashes;
+}
+
 TorrentInfo::PieceRange TorrentInfo::filePieces(const QString& file) const
 {
     if (!isValid()) // if we do not check here the debug message will be printed, which would be not correct

src/base/bittorrent/torrentinfo.h

@@ -91,6 +91,7 @@ namespace BitTorrent
         QByteArray metadata() const;
         QStringList filesForPiece(int pieceIndex) const;
         QVector<int> fileIndicesForPiece(int pieceIndex) const;
+        QVector<QByteArray> pieceHashes() const;
 
         using PieceRange = IndexRange<int>;
         // returns pair of the first and the last pieces into which

src/webui/btjson.cpp

@@ -654,6 +654,59 @@ QByteArray btjson::getFilesForTorrent(const QString& hash)
     return json::toJson(fileList);
 }
 
+/**
+ * Returns an array of hashes (of each pieces respectively) for a torrent in JSON format.
+ *
+ * The return value is a JSON-formatted array of strings (hex strings).
+ */
+QByteArray btjson::getPieceHashesForTorrent(const QString &hash)
+{
+    CACHED_VARIABLE_FOR_HASH(QVariantList, pieceHashes, CACHE_DURATION_MS, hash);
+    BitTorrent::TorrentHandle *const torrent = BitTorrent::Session::instance()->findTorrent(hash);
+    if (!torrent) {
+        qWarning() << Q_FUNC_INFO << "Invalid torrent " << qPrintable(hash);
+        return QByteArray();
+    }
+
+    const QVector<QByteArray> hashes = torrent->info().pieceHashes();
+    pieceHashes.reserve(hashes.size());
+    foreach (const QByteArray &hash, hashes)
+        pieceHashes.append(hash.toHex());
+
+    return json::toJson(pieceHashes);
+}
+
+/**
+ * Returns an array of states (of each pieces respectively) for a torrent in JSON format.
+ *
+ * The return value is a JSON-formatted array of ints.
+ * 0: piece not downloaded
+ * 1: piece requested or downloading
+ * 2: piece already downloaded
+ */
+QByteArray btjson::getPieceStatesForTorrent(const QString &hash)
+{
+    CACHED_VARIABLE_FOR_HASH(QVariantList, pieceStates, CACHE_DURATION_MS, hash);
+    BitTorrent::TorrentHandle *const torrent = BitTorrent::Session::instance()->findTorrent(hash);
+    if (!torrent) {
+        qWarning() << Q_FUNC_INFO << "Invalid torrent " << qPrintable(hash);
+        return QByteArray();
+    }
+
+    const QBitArray states = torrent->pieces();
+    pieceStates.reserve(states.size());
+    for (int i = 0; i < states.size(); ++i)
+        pieceStates.append(static_cast<int>(states[i]) * 2);
+
+    const QBitArray dlstates = torrent->downloadingPieces();
+    for (int i = 0; i < states.size(); ++i) {
+        if (dlstates[i])
+            pieceStates[i] = 1;
+    }
+
+    return json::toJson(pieceStates);
+}
+
 /**
  * Returns the global transfer information in JSON format.
  *

src/webui/btjson.h

@@ -51,6 +51,8 @@ public:
     static QByteArray getWebSeedsForTorrent(const QString& hash);
     static QByteArray getPropertiesForTorrent(const QString& hash);
     static QByteArray getFilesForTorrent(const QString& hash);
+    static QByteArray getPieceHashesForTorrent(const QString &hash);
+    static QByteArray getPieceStatesForTorrent(const QString &hash);
     static QByteArray getTransferInfo();
     static QByteArray getTorrentsRatesLimits(QStringList& hashes, bool downloadLimits);
     static QByteArray getLog(bool normal, bool info, bool warning, bool critical, int lastKnownId);

src/webui/webapplication.cpp

@@ -49,7 +49,7 @@
 #include "websessiondata.h"
 #include "webapplication.h"
 
-static const int API_VERSION = 13;
+static const int API_VERSION = 14;
 static const int API_VERSION_MIN = 13;
 
 const QString WWW_FOLDER = ":/www/public/";
@@ -83,6 +83,8 @@ QMap<QString, QMap<QString, WebApplication::Action> > WebApplication::initialize
     ADD_ACTION(query, propertiesFiles);
     ADD_ACTION(query, getLog);
     ADD_ACTION(query, getPeerLog);
+    ADD_ACTION(query, getPieceHashes);
+    ADD_ACTION(query, getPieceStates);
     ADD_ACTION(sync, maindata);
     ADD_ACTION(sync, torrent_peers);
     ADD_ACTION(command, shutdown);
@@ -310,6 +312,18 @@ void WebApplication::action_query_getPeerLog()
     print(btjson::getPeerLog(lastKnownId), Http::CONTENT_TYPE_JSON);
 }
 
+void WebApplication::action_query_getPieceHashes()
+{
+    CHECK_URI(1);
+    print(btjson::getPieceHashesForTorrent(args_.front()), Http::CONTENT_TYPE_JSON);
+}
+
+void WebApplication::action_query_getPieceStates()
+{
+    CHECK_URI(1);
+    print(btjson::getPieceStatesForTorrent(args_.front()), Http::CONTENT_TYPE_JSON);
+}
+
 // GET param:
 //   - rid (int): last response id
 void WebApplication::action_sync_maindata()

src/webui/webapplication.h

@@ -56,6 +56,8 @@ private:
     void action_query_propertiesFiles();
     void action_query_getLog();
     void action_query_getPeerLog();
+    void action_query_getPieceHashes();
+    void action_query_getPieceStates();
     void action_sync_maindata();
     void action_sync_torrent_peers();
     void action_command_shutdown();