gui: Make Intro consistent with prune checkbox

When prune checkbox is toggled, the related text labels and the amount
of required space shown are updated (previously they were only updated
when the data directory was updated).

2 files changed, 26 insertions, 11 deletions

diff --git a/src/qt/intro.cpp b/src/qt/intro.cpp
index cb7b13260a..873d9dcd6f 100644
--- a/src/qt/intro.cpp
+++ b/src/qt/intro.cpp
@@ -107,6 +107,15 @@ void FreespaceChecker::check()
     Q_EMIT reply(replyStatus, replyMessage, freeBytesAvailable);
 }
 
+namespace {
+//! Return pruning size that will be used if automatic pruning is enabled.
+int GetPruneTargetGB()
+{
+    int64_t prune_target_mib = gArgs.GetArg("-prune", 0);
+    // >1 means automatic pruning is enabled by config, 1 means manual pruning, 0 means no pruning.
+    return prune_target_mib > 1 ? PruneMiBtoGB(prune_target_mib) : DEFAULT_PRUNE_TARGET_GB;
+}
+} // namespace
 
 Intro::Intro(QWidget *parent, int64_t blockchain_size_gb, int64_t chain_state_size_gb) :
     QDialog(parent),
@@ -114,7 +123,8 @@ Intro::Intro(QWidget *parent, int64_t blockchain_size_gb, int64_t chain_state_si
     thread(nullptr),
     signalled(false),
     m_blockchain_size_gb(blockchain_size_gb),
-    m_chain_state_size_gb(chain_state_size_gb)
+    m_chain_state_size_gb(chain_state_size_gb),
+    m_prune_target_gb{GetPruneTargetGB()}
 {
     ui->setupUi(this);
     ui->welcomeLabel->setText(ui->welcomeLabel->text().arg(PACKAGE_NAME));
@@ -128,14 +138,18 @@ Intro::Intro(QWidget *parent, int64_t blockchain_size_gb, int64_t chain_state_si
     );
     ui->lblExplanation2->setText(ui->lblExplanation2->text().arg(PACKAGE_NAME));
 
-    int64_t prune_target_mib = std::max<int64_t>(0, gArgs.GetArg("-prune", 0));
-    if (prune_target_mib > 1) { // -prune=1 means enabled, above that it's a size in MiB
+    if (gArgs.GetArg("-prune", 0) > 1) { // -prune=1 means enabled, above that it's a size in MiB
         ui->prune->setChecked(true);
         ui->prune->setEnabled(false);
     }
-    const int prune_target_gb = PruneMiBtoGB(prune_target_mib);
-    ui->prune->setText(tr("Discard blocks after verification, except most recent %1 GB (prune)").arg(prune_target_gb ? prune_target_gb : DEFAULT_PRUNE_TARGET_GB));
-    UpdatePruneLabels(prune_target_gb);
+    ui->prune->setText(tr("Discard blocks after verification, except most recent %1 GB (prune)").arg(m_prune_target_gb));
+    UpdatePruneLabels(ui->prune->isChecked());
+
+    connect(ui->prune, &QCheckBox::toggled, [this](bool prune_checked) {
+        UpdatePruneLabels(prune_checked);
+        UpdateFreeSpaceLabel();
+    });
+
     startThread();
 }
 
@@ -337,15 +351,15 @@ QString Intro::getPathToCheck()
     return retval;
 }
 
-void Intro::UpdatePruneLabels(int64_t prune_target_gb)
+void Intro::UpdatePruneLabels(bool prune_checked)
 {
     m_required_space_gb = m_blockchain_size_gb + m_chain_state_size_gb;
     QString storageRequiresMsg = tr("At least %1 GB of data will be stored in this directory, and it will grow over time.");
-    if (0 < prune_target_gb && prune_target_gb <= m_blockchain_size_gb) {
-        m_required_space_gb = prune_target_gb + m_chain_state_size_gb;
+    if (prune_checked && m_prune_target_gb <= m_blockchain_size_gb) {
+        m_required_space_gb = m_prune_target_gb + m_chain_state_size_gb;
         storageRequiresMsg = tr("Approximately %1 GB of data will be stored in this directory.");
     }
-    ui->lblExplanation3->setVisible(prune_target_gb > 0);
+    ui->lblExplanation3->setVisible(prune_checked);
     ui->sizeWarningLabel->setText(
         tr("%1 will download and store a copy of the Bitcoin block chain.").arg(PACKAGE_NAME) + " " +
         storageRequiresMsg.arg(m_required_space_gb) + " " +
diff --git a/src/qt/intro.h b/src/qt/intro.h
index 8375847cc0..732393246e 100644
--- a/src/qt/intro.h
+++ b/src/qt/intro.h
@@ -72,11 +72,12 @@ private:
     //! Total required space (in GB) depending on user choice (prune or not prune).
     int64_t m_required_space_gb{0};
     uint64_t m_bytes_available{0};
+    const int64_t m_prune_target_gb;
 
     void startThread();
     void checkPath(const QString &dataDir);
     QString getPathToCheck();
-    void UpdatePruneLabels(int64_t prune_target_gb);
+    void UpdatePruneLabels(bool prune_checked);
     void UpdateFreeSpaceLabel();
 
     friend class FreespaceChecker;