Unify bitcoin-qt and bitcoind persistent settings

If a setting like pruning, port mapping, or a network proxy is enabled in the
GUI, it will now be stored in the bitcoin persistent setting file and shared
with bitcoind, instead of being stored as Qt settings (backed by the windows
registry and platform specific config files).

src/interfaces/node.cpp

@@ -61,9 +61,30 @@ class NodeImpl : public Node
     }
     bool readConfigFiles(std::string& error) override { return gArgs.ReadConfigFiles(error, true); }
     bool softSetArg(const std::string& arg, const std::string& value) override { return gArgs.SoftSetArg(arg, value); }
-    bool softSetBoolArg(const std::string& arg, bool value) override { return gArgs.SoftSetBoolArg(arg, value); }
     void selectParams(const std::string& network) override { SelectParams(network); }
     bool readSettingsFile() override { return gArgs.ReadSettingsFile(); }
+    util::SettingsValue getSetting(const std::string& name) override { return gArgs.GetPersistentSetting(name); }
+    void updateSetting(const std::string& name, const util::SettingsValue& value) override
+    {
+        gArgs.LockSettings([&](util::Settings& settings) {
+            if (value.isNull()) {
+                settings.rw_settings.erase(name);
+            } else {
+                settings.rw_settings[name] = value;
+            }
+        });
+    }
+    bool writeSettingsFile() override { return gArgs.WriteSettingsFile(); }
+    bool isSettingIgnored(const std::string& name) override
+    {
+        bool ignored = false;
+        gArgs.LockSettings([&](util::Settings& settings) {
+            if (auto* options = util::FindKey(settings.command_line_options, name)) {
+                ignored = !options->empty();
+            }
+        });
+        return ignored;
+    }
     uint64_t getAssumedBlockchainSize() override { return Params().AssumedBlockchainSize(); }
     uint64_t getAssumedChainStateSize() override { return Params().AssumedChainStateSize(); }
     std::string getNetwork() override { return Params().NetworkIDString(); }

src/interfaces/node.h

@@ -5,10 +5,11 @@
 #ifndef BITCOIN_INTERFACES_NODE_H
 #define BITCOIN_INTERFACES_NODE_H
 
-#include <addrdb.h>     // For banmap_t
-#include <amount.h>     // For CAmount
-#include <net.h>        // For CConnman::NumConnections
-#include <netaddress.h> // For Network
+#include <addrdb.h>        // For banmap_t
+#include <amount.h>        // For CAmount
+#include <net.h>           // For CConnman::NumConnections
+#include <netaddress.h>    // For Network
+#include <util/settings.h> // For util::SettingsValue
 
 #include <functional>
 #include <memory>
@@ -44,9 +45,6 @@ class Node
     //! Set a command line argument if it doesn't already have a value
     virtual bool softSetArg(const std::string& arg, const std::string& value) = 0;
 
-    //! Set a command line boolean argument if it doesn't already have a value
-    virtual bool softSetBoolArg(const std::string& arg, bool value) = 0;
-
     //! Load settings from configuration file.
     virtual bool readConfigFiles(std::string& error) = 0;
 
@@ -58,6 +56,28 @@ class Node
     //! network-specific.
     virtual bool readSettingsFile() = 0;
 
+    // Return <datadir>/settings.json setting value. If not set will return underlying config value.
+    virtual util::SettingsValue getSetting(const std::string& name) = 0;
+
+    //! Update a setting in <datadir>/settings.json.
+    //!
+    //! Updated setting values are returned by getSetting() and GetArg()
+    //! immediately but are not saved to disk until writeSettingsFile() is
+    //! called.
+    //!
+    //! Setting name should be a command line -option name specified without the
+    //! hyphen prefix. In GetArg() calls, values in settings.json will take
+    //! precedence over values in bitcoin.conf, but will not take precedence
+    //! over values specified explicitly on the command line.
+    virtual void updateSetting(const std::string& name, const util::SettingsValue& value) = 0;
+
+    //! Save <datadir>/settings.json file with updated settings.
+    virtual bool writeSettingsFile() = 0;
+
+    //! Return whether a particular setting in <datadir>/settings.json is or
+    //! would be ignored because it is also specified in the command line.
+    virtual bool isSettingIgnored(const std::string& name) = 0;
+
     //! Get the (assumed) blockchain size.
     virtual uint64_t getAssumedBlockchainSize() = 0;
 

src/qt/forms/optionsdialog.ui

@@ -714,7 +714,7 @@
         <item>
          <widget class="QLabel" name="overriddenByCommandLineInfoLabel">
           <property name="text">
-           <string>Options set in this dialog are overridden by the command line or in the configuration file:</string>
+           <string>Options set in this dialog are overridden by the command line:</string>
           </property>
           <property name="textFormat">
            <enum>Qt::PlainText</enum>

src/qt/intro.cpp

@@ -12,6 +12,7 @@
 
 #include <qt/guiconstants.h>
 #include <qt/guiutil.h>
+#include <qt/optionsmodel.h>
 
 #include <interfaces/node.h>
 #include <util/system.h>
@@ -134,7 +135,7 @@ Intro::Intro(QWidget *parent, uint64_t blockchain_size, uint64_t chain_state_siz
     requiredSpace = m_blockchain_size;
     QString storageRequiresMsg = tr("At least %1 GB of data will be stored in this directory, and it will grow over time.");
     if (pruneTarget) {
-        uint64_t prunedGBs = std::ceil(pruneTarget * 1024 * 1024.0 / GB_BYTES);
+        uint64_t prunedGBs = PruneMiBtoGB(pruneTarget);
         if (prunedGBs <= requiredSpace) {
             requiredSpace = prunedGBs;
             storageRequiresMsg = tr("Approximately %1 GB of data will be stored in this directory.");