Profiler: Add a "Signposts" tab next to the "Samples" tab

This tab provides a filtered listing of all the signpost events in the
currently selected time range.

Userland/DevTools/Profiler/SignpostsModel.cpp

@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "SignpostsModel.h"
+#include "Profile.h"
+#include <AK/StringBuilder.h>
+
+namespace Profiler {
+
+SignpostsModel::SignpostsModel(Profile& profile)
+    : m_profile(profile)
+{
+}
+
+SignpostsModel::~SignpostsModel()
+{
+}
+
+int SignpostsModel::row_count(const GUI::ModelIndex&) const
+{
+    return m_profile.filtered_signpost_indices().size();
+}
+
+int SignpostsModel::column_count(const GUI::ModelIndex&) const
+{
+    return Column::__Count;
+}
+
+String SignpostsModel::column_name(int column) const
+{
+    switch (column) {
+    case Column::SignpostIndex:
+        return "#";
+    case Column::Timestamp:
+        return "Timestamp";
+    case Column::ProcessID:
+        return "PID";
+    case Column::ThreadID:
+        return "TID";
+    case Column::ExecutableName:
+        return "Executable";
+    case Column::SignpostString:
+        return "String";
+    case Column::SignpostArgument:
+        return "Argument";
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
+GUI::Variant SignpostsModel::data(const GUI::ModelIndex& index, GUI::ModelRole role) const
+{
+    u32 event_index = m_profile.filtered_signpost_indices()[index.row()];
+    auto& event = m_profile.events().at(event_index);
+
+    if (role == GUI::ModelRole::Custom) {
+        return event_index;
+    }
+
+    if (role == GUI::ModelRole::Display) {
+        if (index.column() == Column::SignpostIndex)
+            return event_index;
+
+        if (index.column() == Column::ProcessID)
+            return event.pid;
+
+        if (index.column() == Column::ThreadID)
+            return event.tid;
+
+        if (index.column() == Column::ExecutableName) {
+            if (auto* process = m_profile.find_process(event.pid, event.serial))
+                return process->executable;
+            return "";
+        }
+
+        if (index.column() == Column::Timestamp) {
+            return (u32)event.timestamp;
+        }
+
+        if (index.column() == Column::SignpostString) {
+            return event.data.get<Profile::Event::SignpostData>().string;
+        }
+
+        if (index.column() == Column::SignpostArgument) {
+            return event.data.get<Profile::Event::SignpostData>().arg;
+        }
+        return {};
+    }
+    return {};
+}
+
+}