From e279dcf904507c90625d021da0ef6126577a4585 Mon Sep 17 00:00:00 2001
From: "Vladimir Golovnev (Glassez)" <glassez@yandex.ru>
Date: Tue, 25 Nov 2014 09:27:22 +0300
Subject: [PATCH] WebUI: Implement limit/offset.

---
 src/webui/btjson.cpp         | 18 ++++++++++++++++--
 src/webui/btjson.h           |  2 +-
 src/webui/requesthandler.cpp | 10 +++++++++-
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/webui/btjson.cpp b/src/webui/btjson.cpp
index 332ed556b..4ea1483de 100644
--- a/src/webui/btjson.cpp
+++ b/src/webui/btjson.cpp
@@ -235,7 +235,8 @@ static QVariantMap toMap(const QTorrentHandle& h)
  *   - "eta": Torrent ETA
  *   - "state": Torrent state
  */
-QByteArray btjson::getTorrents(QString filter, QString label, QString sortedColumn, bool reverse)
+QByteArray btjson::getTorrents(QString filter, QString label,
+    QString sortedColumn, bool reverse, int limit, int offset)
 {
     QVariantList torrent_list;
 
@@ -252,7 +253,20 @@ QByteArray btjson::getTorrents(QString filter, QString label, QString sortedColu
     }
 
     std::sort(torrent_list.begin(), torrent_list.end(), QTorrentCompare(sortedColumn, reverse));
-    return json::toJson(torrent_list);
+    int size = torrent_list.size();
+    // normalize offset
+    if (offset < 0)
+        offset = size - offset;
+    if ((offset >= size) || (offset < 0))
+        offset = 0;
+    // normalize limit
+    if (limit <= 0)
+        limit = -1; // unlimited
+
+    if ((limit > 0) || (offset > 0))
+        return json::toJson(torrent_list.mid(offset, limit));
+    else
+        return json::toJson(torrent_list);
 }
 
 /**
diff --git a/src/webui/btjson.h b/src/webui/btjson.h
index 0d1a63c56..e8bf66896 100644
--- a/src/webui/btjson.h
+++ b/src/webui/btjson.h
@@ -45,7 +45,7 @@ private:
 
 public:
     static QByteArray getTorrents(QString filter = "all", QString label = QString(),
-        QString sortedColumn = "name", bool reverse = false);
+        QString sortedColumn = "name", bool reverse = false, int limit = 0, int offset = 0);
     static QByteArray getTrackersForTorrent(const QString& hash);
     static QByteArray getPropertiesForTorrent(const QString& hash);
     static QByteArray getFilesForTorrent(const QString& hash);
diff --git a/src/webui/requesthandler.cpp b/src/webui/requesthandler.cpp
index 844fab554..092bd11e3 100644
--- a/src/webui/requesthandler.cpp
+++ b/src/webui/requesthandler.cpp
@@ -186,12 +186,20 @@ void RequestHandler::action_public_images()
     printFile(path);
 }
 
+// GET params:
+//   - filter (string): all, downloading, completed, paused, active, inactive
+//   - label (string): torrent label for filtering by it (empty string means "unlabeled"; no "label" param presented means "any label")
+//   - sort (string): name of column for sorting by its value
+//   - reverse (bool): enable reverse sorting
+//   - limit (int): set limit number of torrents returned (if greater than 0, otherwise - unlimited)
+//   - offset (int): set offset (if less than 0 - offset from end)
 void RequestHandler::action_json_torrents()
 {
     const QStringMap& gets = request().gets;
 
     print(btjson::getTorrents(
-        gets["filter"], gets["label"], gets["sort"], gets["reverse"] == "true"
+        gets["filter"], gets["label"], gets["sort"], gets["reverse"] == "true",
+        gets["limit"].toInt(), gets["offset"].toInt()
         ), CONTENT_TYPE_JS);
 }