GUI: Intro: Have user choose assumevalid

Author: luke-jr

src/qt/bitcoin.cpp

@@ -593,7 +593,7 @@ int GuiMain(int argc, char* argv[])
     if (intro) {
         // Store intro dialog settings other than datadir (network specific)
         app.InitPruneSetting(intro->getPruneMiB());
-        intro.reset();
+        gArgs.ForceSetArg("-assumevalid", intro->getAssumeValid().toStdString());
     }
 
     if (gArgs.GetBoolArg("-splash", DEFAULT_SPLASHSCREEN) && !gArgs.GetBoolArg("-min", false))
@@ -609,6 +609,12 @@ int GuiMain(int argc, char* argv[])
         // This is acceptable because this function only contains steps that are quick to execute,
         // so the GUI thread won't be held up.
         if (app.baseInitialize()) {
+            if (intro) {
+                // Store intro dialog settings other than datadir (network specific)
+                node->context()->chain->updateRwSetting("assumevalid", intro->getAssumeValid().toStdString());
+                // We can release the Intro widget now
+                intro.reset();
+            }
             app.requestInitialize();
 #if defined(Q_OS_WIN)
             WinShutdownMonitor::registerShutdownBlockReason(QObject::tr("%1 didn't yet exit safely...").arg(PACKAGE_NAME), (HWND)app.getMainWinId());

src/qt/bitcoin.h

@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <memory>
 
+#include <interfaces/chain.h>
 #include <interfaces/node.h>
 
 class BitcoinGUI;

src/qt/forms/intro.ui

@@ -271,6 +271,64 @@
      </item>
     </layout>
    </item>
+   <item>
+    <widget class="QWidget" name="groupAssumeValid">
+     <layout class="QVBoxLayout">
+      <item>
+       <widget class="QLabel" name="lblExplanationAssumeValid">
+        <property name="text">
+         <string>The initial synchronisation process can go faster if you skip verification of older transactions. This does, however, require trusting that the &quot;assumed valid&quot; blockchain below is in fact valid. Uncheck this if you want to fully validate the entire blockchain history.</string>
+        </property>
+        <property name="wordWrap">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <layout class="QHBoxLayout" name="layoutAssumeValid">
+        <item>
+         <widget class="QCheckBox" name="assumevalid">
+          <property name="toolTip">
+           <string>Reverting this setting will slow down initial synchronisation due to validating old transactions</string>
+          </property>
+          <property name="text">
+           <string>Skip validation of the transactions until after block:</string>
+          </property>
+          <property name="checked">
+           <bool>true</bool>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <spacer>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </spacer>
+        </item>
+       </layout>
+      </item>
+      <item>
+       <layout class="QHBoxLayout" name="layoutAssumeValidBlock">
+        <item>
+         <spacer>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </spacer>
+        </item>
+        <item>
+         <widget class="QLineEdit" name="assumevalidBlock">
+          <property name="maxLength">
+           <number>64</number>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
+     </layout>
+    </widget>
+   </item>
    <item>
     <spacer name="verticalSpacer">
      <property name="orientation">

src/qt/intro.cpp

@@ -161,6 +161,37 @@ Intro::Intro(QWidget *parent, int64_t blockchain_size_gb, int64_t chain_state_si
         UpdateFreeSpaceLabel();
     });
 
+    bool have_user_assumevalid = false;
+    if (gArgs.IsArgSet("-assumevalid")) {
+        const auto user_assumevalid = gArgs.GetArg("-assumevalid", /* ignored default; determines return type */ "");
+        if (uint256S(user_assumevalid).IsNull()) {
+            // -assumevalid=0: default checkbox to off, and initialise with chainparams later
+            ui->assumevalid->setChecked(false);
+        } else {
+            // -assumevalid=blockhash: initialise with the user-specified value, enabled
+            ui->assumevalid->setChecked(true);
+            ui->assumevalidBlock->setText(QString::fromStdString(user_assumevalid));
+            have_user_assumevalid = true;
+        }
+    }
+    if (!have_user_assumevalid) {
+        const auto chainparams = CreateChainParams(gArgs, gArgs.GetChainName());
+        const uint256 default_assumevalid = chainparams ? chainparams->GetConsensus().defaultAssumeValid : uint256();
+        if (default_assumevalid.IsNull()) {
+            // no chainparams assumevalid (nor user-provided), so hide the options entirely
+            ui->groupAssumeValid->setVisible(false);
+        } else {
+            // assumevalid from chainparams only (normal case): disable editing of blockhash
+            ui->assumevalidBlock->setText(QString::fromStdString(default_assumevalid.GetHex()));
+            ui->assumevalidBlock->setReadOnly(true);
+        }
+    }
+    {
+        // TODO: Ideally, we would include actual margins here (instead of extra digits), but this seems non-trivial
+        const int text_width = ui->assumevalidBlock->fontMetrics().width("4") * (64 + 4);
+        ui->assumevalidBlock->setFixedWidth(text_width);
+    }
+
     startThread();
 }
 
@@ -202,6 +233,14 @@ int64_t Intro::getPruneMiB() const
     }
 }
 
+QString Intro::getAssumeValid() const
+{
+    if (!ui->assumevalid->isChecked()) {
+        return "0";
+    }
+    return ui->assumevalidBlock->text();
+}
+
 bool Intro::showIfNeeded(std::unique_ptr<Intro>& intro)
 {
     intro.reset();

src/qt/intro.h

@@ -39,6 +39,7 @@ class Intro : public QDialog
     QString getDataDirectory();
     void setDataDirectory(const QString &dataDir);
     int64_t getPruneMiB() const;
+    QString getAssumeValid() const;
 
     /**
      * Determine data directory. Let the user choose if the current one doesn't exist.

src/util/settings.h

@@ -11,7 +11,7 @@
 #include <string>
 #include <vector>
 
-class UniValue;
+#include <univalue.h>
 
 namespace util {