kernel: Add warning method to notifications

This commit is part of the libbitcoinkernel project and seeks to remove
the ChainstateManager's and, more generally, the kernel library's
dependency on interface_ui with options methods in this and the following
few commits. By removing interface_ui from the kernel library, its
dependency on boost is reduced to just boost::multi_index.

The DoWarning and AlertNotify functions are moved out of the
validation.cpp file, which removes its dependency on interface_ui as
well as util/system.

src/bitcoin-chainstate.cpp

@@ -99,6 +99,10 @@ int main(int argc, char* argv[])
         {
             std::cout << "Progress: " << title.original << ", " << progress_percent << ", " << resume_possible << std::endl;
         }
+        void warning(const bilingual_str& warning) override
+        {
+            std::cout << "Warning: " << warning.original << std::endl;
+        }
     };
     auto notifications = std::make_unique<KernelNotifications>();
 

src/kernel/notifications_interface.h

@@ -26,6 +26,7 @@ public:
     virtual void blockTip(SynchronizationState state, CBlockIndex& index) {}
     virtual void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) {}
     virtual void progress(const bilingual_str& title, int progress_percent, bool resume_possible) {}
+    virtual void warning(const bilingual_str& warning) {}
 };
 } // namespace kernel
 

src/node/kernel_notifications.cpp

@@ -4,8 +4,51 @@
 
 #include <node/kernel_notifications.h>
 
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#include <common/args.h>
 #include <node/interface_ui.h>
+#include <util/strencodings.h>
+#include <util/string.h>
+#include <util/system.h>
 #include <util/translation.h>
+#include <warnings.h>
+
+#include <cstdint>
+#include <string>
+#include <thread>
+
+static void AlertNotify(const std::string& strMessage)
+{
+    uiInterface.NotifyAlertChanged();
+#if HAVE_SYSTEM
+    std::string strCmd = gArgs.GetArg("-alertnotify", "");
+    if (strCmd.empty()) return;
+
+    // Alert text should be plain ascii coming from a trusted source, but to
+    // be safe we first strip anything not in safeChars, then add single quotes around
+    // the whole string before passing it to the shell:
+    std::string singleQuote("'");
+    std::string safeStatus = SanitizeString(strMessage);
+    safeStatus = singleQuote+safeStatus+singleQuote;
+    ReplaceAll(strCmd, "%s", safeStatus);
+
+    std::thread t(runCommand, strCmd);
+    t.detach(); // thread runs free
+#endif
+}
+
+static void DoWarning(const bilingual_str& warning)
+{
+    static bool fWarned = false;
+    SetMiscWarning(warning);
+    if (!fWarned) {
+        AlertNotify(warning.original);
+        fWarned = true;
+    }
+}
 
 namespace node {
 
@@ -24,4 +67,9 @@ void KernelNotifications::progress(const bilingual_str& title, int progress_perc
     uiInterface.ShowProgress(title.translated, progress_percent, resume_possible);
 }
 
+void KernelNotifications::warning(const bilingual_str& warning)
+{
+    DoWarning(warning);
+}
+
 } // namespace node

src/node/kernel_notifications.h

@@ -23,6 +23,8 @@ public:
     void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) override;
 
     void progress(const bilingual_str& title, int progress_percent, bool resume_possible) override;
+
+    void warning(const bilingual_str& warning) override;
 };
 } // namespace node
 

src/validation.cpp

@@ -27,7 +27,6 @@
 #include <logging.h>
 #include <logging/timer.h>
 #include <node/blockstorage.h>
-#include <node/interface_ui.h>
 #include <node/utxo_snapshot.h>
 #include <policy/policy.h>
 #include <policy/rbf.h>
@@ -53,7 +52,6 @@
 #include <util/moneystr.h>
 #include <util/rbf.h>
 #include <util/strencodings.h>
-#include <util/system.h>
 #include <util/time.h>
 #include <util/trace.h>
 #include <util/translation.h>
@@ -1641,26 +1639,6 @@ bool Chainstate::IsInitialBlockDownload() const
     return false;
 }
 
-static void AlertNotify(const std::string& strMessage)
-{
-    uiInterface.NotifyAlertChanged();
-#if HAVE_SYSTEM
-    std::string strCmd = gArgs.GetArg("-alertnotify", "");
-    if (strCmd.empty()) return;
-
-    // Alert text should be plain ascii coming from a trusted source, but to
-    // be safe we first strip anything not in safeChars, then add single quotes around
-    // the whole string before passing it to the shell:
-    std::string singleQuote("'");
-    std::string safeStatus = SanitizeString(strMessage);
-    safeStatus = singleQuote+safeStatus+singleQuote;
-    ReplaceAll(strCmd, "%s", safeStatus);
-
-    std::thread t(runCommand, strCmd);
-    t.detach(); // thread runs free
-#endif
-}
-
 void Chainstate::CheckForkWarningConditions()
 {
     AssertLockHeld(cs_main);
@@ -2601,16 +2579,6 @@ void Chainstate::PruneAndFlush()
     }
 }
 
-static void DoWarning(const bilingual_str& warning)
-{
-    static bool fWarned = false;
-    SetMiscWarning(warning);
-    if (!fWarned) {
-        AlertNotify(warning.original);
-        fWarned = true;
-    }
-}
-
 /** Private helper function that concatenates warning messages. */
 static void AppendWarning(bilingual_str& res, const bilingual_str& warn)
 {
@@ -2677,7 +2645,7 @@ void Chainstate::UpdateTip(const CBlockIndex* pindexNew)
             if (state == ThresholdState::ACTIVE || state == ThresholdState::LOCKED_IN) {
                 const bilingual_str warning = strprintf(_("Unknown new rules activated (versionbit %i)"), bit);
                 if (state == ThresholdState::ACTIVE) {
-                    DoWarning(warning);
+                    m_chainman.GetNotifications().warning(warning);
                 } else {
                     AppendWarning(warning_messages, warning);
                 }