Fine-grained UI updates

Gets rid of `MainFrameRepaint` in favor of specific update functions that tell the UI exactly what changed.

This improves the efficiency of various handlers. Also fixes problems with mined transactions not showing up until restart.

The following notifications were added:

- `NotifyBlocksChanged`: Block chain changed
- `NotifyKeyStoreStatusChanged`: Wallet status (encrypted, locked) changed.
- `NotifyAddressBookChanged`: Address book entry changed.
- `NotifyTransactionChanged`: Wallet transaction added, removed or updated.
- `NotifyNumConnectionsChanged`: Number of connections changed.
- `NotifyAlertChanged`: New, updated or cancelled alert. As this finally makes it possible for the UI to know when a new alert arrived, it can be shown as OS notification.

These notifications could also be useful for RPC clients. However, currently, they are ignored in bitcoind (in noui.cpp).

Also brings back polling with timer for numBlocks in ClientModel. This value updates so frequently during initial download that the number of signals clogs the UI thread and causes heavy CPU usage. And after initial block download, the value changes so rarely that a delay of half a second until the UI updates is unnoticable.

1 files changed, 40 insertions, 17 deletions

diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index 85ab03612d..1914ef90b5 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -5,15 +5,23 @@
 #include "transactiontablemodel.h"
 
 #include "main.h"
-static const int64 nClientStartupTime = GetTime();
+#include "ui_interface.h"
 
 #include <QDateTime>
+#include <QTimer>
+
+static const int64 nClientStartupTime = GetTime();
 
 ClientModel::ClientModel(OptionsModel *optionsModel, QObject *parent) :
     QObject(parent), optionsModel(optionsModel),
-    cachedNumConnections(0), cachedNumBlocks(0)
+    cachedNumBlocks(0), cachedNumBlocksOfPeers(0), pollTimer(0)
 {
     numBlocksAtStartup = -1;
+
+    pollTimer = new QTimer();
+    pollTimer->setInterval(MODEL_UPDATE_DELAY);
+    pollTimer->start();
+    connect(pollTimer, SIGNAL(timeout()), this, SLOT(updateTimer()));
 }
 
 int ClientModel::getNumConnections() const
@@ -37,27 +45,42 @@ QDateTime ClientModel::getLastBlockDate() const
     return QDateTime::fromTime_t(pindexBest->GetBlockTime());
 }
 
-void ClientModel::update()
+void ClientModel::updateTimer()
 {
-    int newNumConnections = getNumConnections();
+    // Some quantities (such as number of blocks) change so fast that we don't want to be notified for each change.
+    // Periodically check and update with a timer.
     int newNumBlocks = getNumBlocks();
-    QString newStatusBar = getStatusBarWarnings();
+    int newNumBlocksOfPeers = getNumBlocksOfPeers();
 
-    if(cachedNumConnections != newNumConnections)
-        emit numConnectionsChanged(newNumConnections);
-    if(cachedNumBlocks != newNumBlocks || cachedStatusBar != newStatusBar)
+    if(cachedNumBlocks != newNumBlocks || cachedNumBlocksOfPeers != newNumBlocksOfPeers)
+        emit numBlocksChanged(newNumBlocks, newNumBlocksOfPeers);
+
+    cachedNumBlocks = newNumBlocks;
+    cachedNumBlocksOfPeers = newNumBlocksOfPeers;
+}
+
+void ClientModel::updateNumConnections(int numConnections)
+{
+    emit numConnectionsChanged(numConnections);
+}
+
+void ClientModel::updateAlert(const QString &hash, int status)
+{
+    // Show error message notification for new alert
+    if(status == CT_NEW)
     {
-        // Simply emit a numBlocksChanged for now in case the status message changes,
-        // so that the view updates the status bar.
-        // TODO: It should send a notification.
-        //    (However, this might generate looped notifications and needs to be thought through and tested carefully)
-        //    error(tr("Network Alert"), newStatusBar);
-        emit numBlocksChanged(newNumBlocks);
+        uint256 hash_256;
+        hash_256.SetHex(hash.toStdString());
+        CAlert alert = CAlert::getAlertByHash(hash_256);
+        if(!alert.IsNull())
+        {
+            emit error(tr("Network Alert"), QString::fromStdString(alert.strStatusBar), false);
+        }
     }
 
-    cachedNumConnections = newNumConnections;
-    cachedNumBlocks = newNumBlocks;
-    cachedStatusBar = newStatusBar;
+    // Emit a numBlocksChanged when the status message changes,
+    // so that the view recomputes and updates the status bar.
+    emit numBlocksChanged(getNumBlocks(), getNumBlocksOfPeers());
 }
 
 bool ClientModel::isTestNet() const