Merge #17696: qt: Force set nPruneSize in QSettings after the intro dialog

af112ab62895b145660f4cd7ff842e9cfea2a530 qt: Rename SetPrune() to InitializePruneSetting() (Hennadii Stepanov)
b0bfbe50282877a1eee87118902901a280d6656d refactor: Drop `bool force' parameter (Hennadii Stepanov)
68c9bbe9bc91f882404556998666b1b5acea60e4 qt: Force set nPruneSize in QSettings after intro (Hennadii Stepanov)
a82bd8fa5708c16d1db3edc4e82d70788eb5af19 util: Replace magics with DEFAULT_PRUNE_TARGET_GB (Hennadii Stepanov)

Pull request description:

  On master (5622d8f3156a293e61d0964c33d4b21d8c9fd5e0), having `QSettings` set already
  ```
  $ grep nPruneSize ~/.config/Bitcoin/Bitcoin-Qt-testnet.conf
  nPruneSize=6
  ```

  enabling prune option in the intro dialog

  ```
  $ ./src/qt/bitcoin-qt -choosedatadir -testnet
  ```
  ![DeepinScreenshot_select-area_20191208120425](https://user-images.githubusercontent.com/32963518/70388183-eed68580-19b6-11ea-9aa1-f9ad9aaa68a6.png)

  has no effect:
  ```
  $ grep Prune ~/.bitcoin/testnet3/debug.log
  2019-12-08T10:04:41Z Prune configured to target 5722 MiB on disk for block and undo files.
  ```

  ---

  With this PR:
  ```
  $ grep Prune ~/.bitcoin/testnet3/debug.log
  2019-12-08T10:20:35Z Prune configured to target 1907 MiB on disk for block and undo files.
  ```

  This PR has been split of #17453 (the first two commits) as it fixes an orthogonal bug.

  Refs:
  - https://github.com/bitcoin/bitcoin/pull/17453#discussion_r345424240
  - https://github.com/bitcoin/bitcoin/pull/17453#discussion_r350960201

ACKs for top commit:
  Sjors:
    Code review re-ACK af112ab62895b145660f4cd7ff842e9cfea2a530
  ryanofsky:
    Code review ACK af112ab62895b145660f4cd7ff842e9cfea2a530. Just suggested changes since last review (thanks!)
  promag:
    Tested ACK af112ab62895b145660f4cd7ff842e9cfea2a530. Latest suggestions and changes look good to me.

Tree-SHA512: 8ddad34b30dcc2cdcad6678ba8a0b36fa176e4e3465862ef6eee9be0f98d8146705138c9c7995dd8c0990af41078ca743fef1a90ed9240081f052f32ddec72b9

1 files changed, 13 insertions, 3 deletions

diff --git a/src/qt/optionsmodel.cpp b/src/qt/optionsmodel.cpp
index ec18cdf3f8..df5248f55e 100644
--- a/src/qt/optionsmodel.cpp
+++ b/src/qt/optionsmodel.cpp
@@ -91,8 +91,8 @@ void OptionsModel::Init(bool resetSettings)
     if (!settings.contains("bPrune"))
         settings.setValue("bPrune", false);
     if (!settings.contains("nPruneSize"))
-        settings.setValue("nPruneSize", 2);
-    SetPrune(settings.value("bPrune").toBool());
+        settings.setValue("nPruneSize", DEFAULT_PRUNE_TARGET_GB);
+    SetPruneEnabled(settings.value("bPrune").toBool());
 
     if (!settings.contains("nDatabaseCache"))
         settings.setValue("nDatabaseCache", (qint64)nDefaultDbCache);
@@ -236,7 +236,7 @@ static const QString GetDefaultProxyAddress()
     return QString("%1:%2").arg(DEFAULT_GUI_PROXY_HOST).arg(DEFAULT_GUI_PROXY_PORT);
 }
 
-void OptionsModel::SetPrune(bool prune, bool force)
+void OptionsModel::SetPruneEnabled(bool prune, bool force)
 {
     QSettings settings;
     settings.setValue("bPrune", prune);
@@ -252,6 +252,16 @@ void OptionsModel::SetPrune(bool prune, bool force)
     }
 }
 
+void OptionsModel::SetPruneTargetGB(int prune_target_gb, bool force)
+{
+    const bool prune = prune_target_gb > 0;
+    if (prune) {
+        QSettings settings;
+        settings.setValue("nPruneSize", prune_target_gb);
+    }
+    SetPruneEnabled(prune, force);
+}
+
 // read QSettings values and return them
 QVariant OptionsModel::data(const QModelIndex & index, int role) const
 {