ProcessManager: Add a "Memory map" view to show a process's VM layout.

Fetch all the data from /proc/PID/vm for the selected process and show it
in a nice GTableView. :^)

Applications/ProcessManager/ProcessMemoryMapModel.cpp

@@ -0,0 +1,98 @@
+#include "ProcessMemoryMapModel.h"
+#include <AK/JsonObject.h>
+#include <AK/StringBuilder.h>
+#include <LibCore/CFile.h>
+
+void ProcessMemoryMapModel::update()
+{
+    CFile file(String::format("/proc/%d/vm", m_pid));
+    if (!file.open(CIODevice::ReadOnly)) {
+        dbg() << "Unable to open " << file.filename();
+        return;
+    }
+
+    auto json = JsonValue::from_string(file.read_all());
+
+    ASSERT(json.is_array());
+    m_process_vm = json.as_array();
+
+    did_update();
+}
+
+int ProcessMemoryMapModel::row_count(const GModelIndex&) const
+{
+    return m_process_vm.size();
+}
+
+String ProcessMemoryMapModel::column_name(int column) const
+{
+    switch (column) {
+    case Column::Address:
+        return "Address";
+    case Column::Size:
+        return "Size";
+    case Column::AmountResident:
+        return "Resident";
+    case Column::Access:
+        return "Access";
+    case Column::Name:
+        return "Name";
+    default:
+        ASSERT_NOT_REACHED();
+    }
+}
+
+GModel::ColumnMetadata ProcessMemoryMapModel::column_metadata(int column) const
+{
+    switch (column) {
+    case Column::Address:
+        return { 80 };
+    case Column::Size:
+        return { 60, TextAlignment::CenterRight };
+    case Column::AmountResident:
+        return { 60, TextAlignment::CenterRight };
+    case Column::Access:
+        return { 50 };
+    case Column::Name:
+        return { 200 };
+    default:
+        ASSERT_NOT_REACHED();
+    }
+    return {};
+}
+
+GVariant ProcessMemoryMapModel::data(const GModelIndex& index, Role role) const
+{
+    auto& region_object = m_process_vm.at(index.row()).as_object();
+    if (role == GModel::Role::Display) {
+        switch (index.column()) {
+        case Column::Address:
+            return String::format("%#x", region_object.get("address").to_u32());
+        case Column::Size:
+            return region_object.get("size").to_int();
+        case Column::AmountResident:
+            return region_object.get("amount_resident").to_int();
+        case Column::Access: {
+            StringBuilder builder;
+            if (region_object.get("readable").to_bool())
+                builder.append('R');
+            if (region_object.get("writable").to_bool())
+                builder.append('W');
+            return builder.to_string();
+        }
+        case Column::Name:
+            return region_object.get("name").to_string();
+        default:
+            ASSERT_NOT_REACHED();
+        }
+    }
+    return {};
+}
+
+void ProcessMemoryMapModel::set_pid(pid_t pid)
+{
+    if (m_pid == pid)
+        return;
+    m_pid = pid;
+    update();
+}