Merge bitcoin/bitcoin#27636: kernel: Remove util/system from kernel library, interface_ui from validation.

7d3b35004b refactor: Move system from util to common library (TheCharlatan)
7eee356c0a refactor: Split util::AnyPtr into its own file (TheCharlatan)
44de325d95 refactor: Split util::insert into its own file (TheCharlatan)
9ec5da36b6 refactor: Move ScheduleBatchPriority to its own file (TheCharlatan)
f871c69191 kernel: Add warning method to notifications (TheCharlatan)
4452707ede kernel: Add progress method to notifications (TheCharlatan)
84d71457e7 kernel: Add headerTip method to notifications (TheCharlatan)
447761c822 kernel: Add notification interface (TheCharlatan)

Pull request description:

  This pull request is part of the `libbitcoinkernel` project https://github.com/bitcoin/bitcoin/issues/27587 https://github.com/bitcoin/bitcoin/projects/18 and more specifically its "Step 2: Decouple most non-consensus code from libbitcoinkernel".

  ---

  It removes the kernel library's dependency on `util/system` and `interface_ui`. `util/system` contains networking and shell-related code that should not be part of the kernel library. The following pull requests prepared `util/system` for this final step: https://github.com/bitcoin/bitcoin/pull/27419 https://github.com/bitcoin/bitcoin/pull/27254 https://github.com/bitcoin/bitcoin/pull/27238.

  `interface_ui` defines functions for a more general node interface and has a dependency on `boost/signals2`. After applying the patches from this pull request, the kernel's reliance on boost is down to `boost::multiindex`.

  The approach implemented here introduces some indirection, which makes the code a bit harder to read. Any suggestions for improving or reworking this pull request to make it more concise, or even reworking it into a more proper interface, are appreciated.

ACKs for top commit:
  MarcoFalke:
    re-ACK 7d3b35004b (no change) 🎋
  stickies-v:
    Code Review ACK 7d3b35004b
  hebasto:
    re-ACK 7d3b35004b, only last two commits dropped since my [recent](https://github.com/bitcoin/bitcoin/pull/27636#pullrequestreview-1435394620) review.

Tree-SHA512: c8cfc698dc9d78e20191c444708f2d957501229abe95e5806106d1126fb9c5fbcee686fb55645658c0107ce71f10646f37a2fdf7fde16bbf22cbf1ac885dd08d

src/node/blockstorage.cpp

@@ -17,9 +17,9 @@
 #include <signet.h>
 #include <streams.h>
 #include <undo.h>
+#include <util/batchpriority.h>
 #include <util/fs.h>
 #include <util/syscall_sandbox.h>
-#include <util/system.h>
 #include <validation.h>
 
 #include <map>

src/node/chainstate.cpp

@@ -253,7 +253,7 @@ ChainstateLoadResult VerifyLoadedChainstate(ChainstateManager& chainman, const C
                                                          "Only rebuild the block database if you are sure that your computer's date and time are correct")};
             }
 
-            VerifyDBResult result = CVerifyDB().VerifyDB(
+            VerifyDBResult result = CVerifyDB(chainman.GetNotifications()).VerifyDB(
                 *chainstate, chainman.GetConsensus(), chainstate->CoinsDB(),
                 options.check_level,
                 options.check_blocks);

src/node/context.cpp

@@ -11,6 +11,7 @@
 #include <net.h>
 #include <net_processing.h>
 #include <netgroup.h>
+#include <node/kernel_notifications.h>
 #include <policy/fees.h>
 #include <scheduler.h>
 #include <txmempool.h>

src/node/context.h

@@ -30,6 +30,8 @@ class WalletLoader;
 } // namespace interfaces
 
 namespace node {
+class KernelNotifications;
+
 //! NodeContext struct containing references to chain state and connection
 //! state.
 //!
@@ -62,6 +64,7 @@ struct NodeContext {
     interfaces::WalletLoader* wallet_loader{nullptr};
     std::unique_ptr<CScheduler> scheduler;
     std::function<void()> rpc_interruption_point = [] {};
+    std::unique_ptr<KernelNotifications> notifications;
 
     //! Declare default constructor and destructor that are not inline, so code
     //! instantiating the NodeContext struct doesn't need to #include class

src/node/kernel_notifications.cpp

@@ -0,0 +1,75 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <node/kernel_notifications.h>
+
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#include <common/args.h>
+#include <common/system.h>
+#include <node/interface_ui.h>
+#include <util/strencodings.h>
+#include <util/string.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 {
+
+void KernelNotifications::blockTip(SynchronizationState state, CBlockIndex& index)
+{
+    uiInterface.NotifyBlockTip(state, &index);
+}
+
+void KernelNotifications::headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync)
+{
+    uiInterface.NotifyHeaderTip(state, height, timestamp, presync);
+}
+
+void KernelNotifications::progress(const bilingual_str& title, int progress_percent, bool resume_possible)
+{
+    uiInterface.ShowProgress(title.translated, progress_percent, resume_possible);
+}
+
+void KernelNotifications::warning(const bilingual_str& warning)
+{
+    DoWarning(warning);
+}
+
+} // namespace node

src/node/kernel_notifications.h

@@ -0,0 +1,31 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NODE_KERNEL_NOTIFICATIONS_H
+#define BITCOIN_NODE_KERNEL_NOTIFICATIONS_H
+
+#include <kernel/notifications_interface.h>
+
+#include <cstdint>
+#include <string>
+
+class CBlockIndex;
+enum class SynchronizationState;
+struct bilingual_str;
+
+namespace node {
+class KernelNotifications : public kernel::Notifications
+{
+public:
+    void blockTip(SynchronizationState state, CBlockIndex& index) override;
+
+    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
+
+#endif // BITCOIN_NODE_KERNEL_NOTIFICATIONS_H

src/node/txreconciliation.cpp

@@ -4,9 +4,9 @@
 
 #include <node/txreconciliation.h>
 
+#include <common/system.h>
 #include <logging.h>
 #include <util/check.h>
-#include <util/system.h>
 
 #include <unordered_map>
 #include <variant>