From bc18bf1ab4f4fe11325b7255152261bf782778ed Mon Sep 17 00:00:00 2001
From: Eugene Shalygin <eugene.shalygin@gmail.com>
Date: Tue, 22 Mar 2016 18:10:12 +0100
Subject: [PATCH] Add TorrentHandle::availableFileFractions() function

The function returns list of availability values for all torrent files.
The availability here is different to that one in the progress bar. Here
it shows what part of the file's pieces is available (i.e. we do not count
availability > 1 for a piece).
---
 src/base/bittorrent/torrenthandle.cpp | 21 +++++++++++++++++++++
 src/base/bittorrent/torrenthandle.h   |  8 ++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/base/bittorrent/torrenthandle.cpp b/src/base/bittorrent/torrenthandle.cpp
index a6436ec34..f9ad2c697 100644
--- a/src/base/bittorrent/torrenthandle.cpp
+++ b/src/base/bittorrent/torrenthandle.cpp
@@ -1953,3 +1953,24 @@ void TorrentHandle::prioritizeFiles(const QVector<int> &priorities)
 
     updateStatus();
 }
+
+QVector<qreal> TorrentHandle::availableFileFractions() const
+{
+    QVector<int> piecesAvailability = pieceAvailability();
+    const auto filesCount = this->filesCount();
+    // libtorrent returns empty array for seeding only torrents
+    if (piecesAvailability.empty()) return QVector<qreal>(filesCount, -1.);
+
+    QVector<qreal> res;
+    res.reserve(filesCount);
+    TorrentInfo info = this->info();
+    for (int file = 0; file < filesCount; ++file) {
+        TorrentInfo::PieceRange filePieces = info.filePieces(file);
+        int availablePieces = 0;
+        for (int piece = filePieces.first(); piece <= filePieces.last(); ++piece) {
+            availablePieces += piecesAvailability[piece] > 0 ? 1 : 0;
+        }
+        res.push_back(static_cast<qreal>(availablePieces) / filePieces.size());
+    }
+    return res;
+}
diff --git a/src/base/bittorrent/torrenthandle.h b/src/base/bittorrent/torrenthandle.h
index 8cdcfe02e..cb0c183cc 100644
--- a/src/base/bittorrent/torrenthandle.h
+++ b/src/base/bittorrent/torrenthandle.h
@@ -361,6 +361,14 @@ namespace BitTorrent
         void handleAppendExtensionToggled();
         void saveResumeData(bool updateStatus = false);
 
+        /**
+         * @brief fraction of file pieces that are available at least from one peer
+         *
+         * This is not the same as torrrent availability, it is just a fraction of pieces
+         * that can be downloaded right now. It varies between 0 to 1.
+         */
+        QVector<qreal> availableFileFractions() const;
+
     private:
         typedef boost::function<void ()> EventTrigger;