From 6e07ead572095c2e934010c803c95e5777c228de Mon Sep 17 00:00:00 2001
From: csoler <csoler@users.sourceforge.net>
Date: Sun, 12 Jul 2020 18:02:44 +0200
Subject: [PATCH] added display of 10-posts chunks

---
 .../src/gui/Posted/PostedPostsModel.cpp       | 41 ++++++++++++++++---
 .../src/gui/Posted/PostedPostsModel.h         | 38 +++++++++++++++--
 2 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/retroshare-gui/src/gui/Posted/PostedPostsModel.cpp b/retroshare-gui/src/gui/Posted/PostedPostsModel.cpp
index b7e4226a6..dbe5239f4 100644
--- a/retroshare-gui/src/gui/Posted/PostedPostsModel.cpp
+++ b/retroshare-gui/src/gui/Posted/PostedPostsModel.cpp
@@ -38,6 +38,8 @@
 Q_DECLARE_METATYPE(RsMsgMetaData)
 Q_DECLARE_METATYPE(RsPostedPost)
 
+const uint32_t RsPostedPostsModel::DEFAULT_DISPLAYED_NB_POSTS = 10;
+
 std::ostream& operator<<(std::ostream& o, const QModelIndex& i);// defined elsewhere
 
 RsPostedPostsModel::RsPostedPostsModel(QObject *parent)
@@ -121,6 +123,8 @@ void RsPostedPostsModel::initEmptyHierarchy()
 
     mPosts.clear();
     mFilteredPosts.clear();
+    mDisplayedNbPosts = DEFAULT_DISPLAYED_NB_POSTS;
+    mDisplayedStartIndex = 0;
 
     postMods();
 }
@@ -167,6 +171,9 @@ void RsPostedPostsModel::setFilter(const QStringList& strings, uint32_t& count)
     }
     count = mFilteredPosts.size();
 
+    if(mDisplayedNbPosts > count)
+        mDisplayedNbPosts = count;
+
     std::cerr << "After filtering: " << count << " posts remain." << std::endl;
 
 	beginInsertRows(QModelIndex(),0,rowCount()-1);
@@ -184,7 +191,7 @@ int RsPostedPostsModel::rowCount(const QModelIndex& parent) const
         return 0;
 
     if(!parent.isValid())
-		return mFilteredPosts.size() ;
+		return mDisplayedNbPosts;
 
     RsErr() << __PRETTY_FUNCTION__ << " rowCount cannot figure out the porper number of rows." << std::endl;
     return 0;
@@ -413,7 +420,6 @@ void RsPostedPostsModel::clear()
 {
     preMods();
 
-    mPosts.clear();
     initEmptyHierarchy();
 
 	postMods();
@@ -458,6 +464,27 @@ void RsPostedPostsModel::setSortingStrategy(RsPostedPostsModel::SortingStrategy
 	postMods();
 }
 
+void RsPostedPostsModel::setPostsInterval(int start,int nb_posts)
+{
+    if(start >= mFilteredPosts.size())
+        return;
+
+	preMods();
+
+    uint32_t old_nb_rows = rowCount() ;
+
+    mDisplayedNbPosts = (uint32_t)std::min(nb_posts,(int)mFilteredPosts.size() - (start+1));
+    mDisplayedStartIndex = start;
+
+	beginRemoveRows(QModelIndex(),mDisplayedNbPosts,old_nb_rows);
+    endRemoveRows();
+
+	beginInsertRows(QModelIndex(),old_nb_rows,mDisplayedNbPosts);
+    endInsertRows();
+
+	postMods();
+}
+
 void RsPostedPostsModel::setPosts(const RsPostedGroup& group, std::vector<RsPostedPost>& posts)
 {
     preMods();
@@ -470,11 +497,13 @@ void RsPostedPostsModel::setPosts(const RsPostedGroup& group, std::vector<RsPost
 
     createPostsArray(posts);
 
-    std::sort(mPosts.begin(),mPosts.end(), PostSorter(RsPostedPostsModel::SORT_NEW_SCORE));
+    std::sort(mPosts.begin(),mPosts.end(), PostSorter(SORT_NEW_SCORE));
 
-    mFilteredPosts.clear();
-    for(int i=0;i<mPosts.size();++i)
-        mFilteredPosts.push_back(i);
+    uint32_t tmpval;
+    setFilter(QStringList(),tmpval);
+
+    mDisplayedNbPosts = std::min((uint32_t)mFilteredPosts.size(),DEFAULT_DISPLAYED_NB_POSTS);
+    mDisplayedStartIndex = 0;
 
 	beginInsertRows(QModelIndex(),0,rowCount()-1);
     endInsertRows();
diff --git a/retroshare-gui/src/gui/Posted/PostedPostsModel.h b/retroshare-gui/src/gui/Posted/PostedPostsModel.h
index d1a02ad98..ba78dc590 100644
--- a/retroshare-gui/src/gui/Posted/PostedPostsModel.h
+++ b/retroshare-gui/src/gui/Posted/PostedPostsModel.h
@@ -31,6 +31,33 @@
 
 // The model contains a post in place 0 that is the parent of all posts.
 
+// The model contains 3 layers:
+//
+//   Layer 1: list of all posts
+//
+//    * this list is sorted according to the current sorting strategy
+//    * Variables: mPosts
+//
+//   Layer 2: list of post filtered by search
+//
+//    * depending on which chunk of posts are actually displayed, this list contains
+//      the subset of the general list of posts
+//    * Variables: mFilteredPosts
+//
+//   Layer 3: start and end of posts actually displayed in the previous list
+//
+//    * Variables: mDisplayedStartIndex, mDisplayedNbPosts
+//
+// The array below indicates which variables are updated depending on the type of data/view change:
+//
+//             |  Global list (mPosts) | Filtered List    |  Displayed list (mDisplayedStartIndex, mDisplayedNbPosts)
+//  -----------+-----------------------+------------------+----------------------------------------------------------
+//  New group  |           X           |        X         |  X (updated because FilteredList may change)
+//  Sort order |           X           |                  |
+//  Filter Str |                       |        X         |  X (updated because FilteredList may change)
+//  Chunk chng |                       |        X         |  X
+//
+
 typedef uint32_t PostedPostsModelIndex;
 
 // struct ChannelPostsModelPostEntry
@@ -66,7 +93,8 @@ public:
 	explicit RsPostedPostsModel(QObject *parent = NULL);
 	virtual ~RsPostedPostsModel() override;
 
-	static const int COLUMN_THREAD_NB_COLUMNS = 0x01;
+	static const uint32_t COLUMN_THREAD_NB_COLUMNS   = 0x01;
+	static const uint32_t DEFAULT_DISPLAYED_NB_POSTS ;
 
     enum SortingStrategy {
         SORT_UNKNOWN         = 0x00,
@@ -118,6 +146,7 @@ public:
 	void setMsgReadStatus(const QModelIndex &i, bool read_status, bool with_children);
     void setFilter(const QStringList &strings, uint32_t &count) ;
 	void setSortingStrategy(SortingStrategy s);
+	void setPostsInterval(int start,int nb_posts);
 
 #ifdef TODO
 	void setAuthorOpinion(const QModelIndex& indx,RsOpinion op);
@@ -198,8 +227,11 @@ private:
 	void initEmptyHierarchy();
 	void handleEvent_main_thread(std::shared_ptr<const RsEvent> event);
 
-    std::vector<int> mFilteredPosts;		// stores the list of displayes indices due to filtering.
-    std::vector<RsPostedPost> mPosts ;  // store the list of posts updated from rsForums.
+    std::vector<RsPostedPost> mPosts ;
+    std::vector<int> mFilteredPosts;
+    uint32_t mDisplayedStartIndex;
+    uint32_t mDisplayedNbPosts;
+
 
 	RsEventsHandlerId_t mEventHandlerId ;
 };