Help+LibManual: Move non-UI-specific manual handling to LibManual

This is a first step in deduplicating code within and across Help and
man.

Because LibManual also doesn't contain any DeprecatedString, some
adjustments to Help's string handling is included, just to interoperate
with LibManual better. Further work in this area mostly requires String
APIs in LibGUI.

Userland/Libraries/LibManual/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(SOURCES
+    PageNode.cpp
+    SectionNode.cpp
+)
+
+serenity_lib(LibManual manual)
+target_link_libraries(LibManual PRIVATE LibCore)

Userland/Libraries/LibManual/Node.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/NonnullRefPtrVector.h>
+#include <AK/RefCounted.h>
+#include <AK/String.h>
+#include <AK/StringView.h>
+
+namespace Manual {
+
+class PageNode;
+
+class Node : public RefCounted<Node> {
+public:
+    virtual ~Node() = default;
+
+    virtual NonnullRefPtrVector<Node>& children() const = 0;
+    virtual Node const* parent() const = 0;
+    virtual String name() const = 0;
+    virtual bool is_page() const { return false; }
+    virtual bool is_open() const { return false; }
+};
+
+}

Userland/Libraries/LibManual/PageNode.cpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "PageNode.h"
+#include "SectionNode.h"
+
+namespace Manual {
+
+Node const* PageNode::parent() const
+{
+    return m_section.ptr();
+}
+
+NonnullRefPtrVector<Node>& PageNode::children() const
+{
+    static NonnullRefPtrVector<Node> empty_vector;
+    return empty_vector;
+}
+
+ErrorOr<String> PageNode::path() const
+{
+    return TRY(String::formatted("{}/{}.md", TRY(m_section->path()), m_page));
+}
+
+}

Userland/Libraries/LibManual/PageNode.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <LibManual/Node.h>
+
+namespace Manual {
+
+class SectionNode;
+
+class PageNode : public Node {
+public:
+    virtual ~PageNode() override = default;
+
+    PageNode(NonnullRefPtr<SectionNode> section, String page)
+        : m_section(move(section))
+        , m_page(move(page))
+    {
+    }
+
+    virtual NonnullRefPtrVector<Node>& children() const override;
+    virtual Node const* parent() const override;
+    virtual String name() const override { return m_page; };
+    virtual bool is_page() const override { return true; }
+
+    ErrorOr<String> path() const;
+
+private:
+    NonnullRefPtr<SectionNode> m_section;
+    String m_page;
+};
+
+}

Userland/Libraries/LibManual/SectionNode.cpp

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "SectionNode.h"
+#include "PageNode.h"
+#include <AK/LexicalPath.h>
+#include <AK/QuickSort.h>
+#include <LibCore/DirIterator.h>
+
+namespace Manual {
+
+ErrorOr<String> SectionNode::path() const
+{
+    return String::formatted("/usr/share/man/man{}", m_section);
+}
+
+ErrorOr<void> SectionNode::reify_if_needed() const
+{
+    if (m_reified)
+        return {};
+    m_reified = true;
+
+    Core::DirIterator dir_iter { TRY(path()).to_deprecated_string(), Core::DirIterator::Flags::SkipDots };
+
+    Vector<String> page_names;
+    while (dir_iter.has_next()) {
+        LexicalPath lexical_path(dir_iter.next_path());
+        if (lexical_path.extension() != "md")
+            continue;
+        page_names.append(TRY(String::from_utf8(lexical_path.title())));
+    }
+
+    quick_sort(page_names);
+
+    for (auto& page_name : page_names)
+        m_children.append(TRY(try_make_ref_counted<PageNode>(*this, move(page_name))));
+
+    return {};
+}
+
+void SectionNode::set_open(bool open)
+{
+    if (m_open == open)
+        return;
+    m_open = open;
+}
+
+Array<NonnullRefPtr<SectionNode>, number_of_sections> const sections = { {
+    make_ref_counted<SectionNode>("1"sv, "User Programs"sv),
+    make_ref_counted<SectionNode>("2"sv, "System Calls"sv),
+    make_ref_counted<SectionNode>("3"sv, "Library Functions"sv),
+    make_ref_counted<SectionNode>("4"sv, "Special Files"sv),
+    make_ref_counted<SectionNode>("5"sv, "File Formats"sv),
+    make_ref_counted<SectionNode>("6"sv, "Games"sv),
+    make_ref_counted<SectionNode>("7"sv, "Miscellanea"sv),
+    make_ref_counted<SectionNode>("8"sv, "Sysadmin Tools"sv),
+} };
+
+}

Userland/Libraries/LibManual/SectionNode.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/String.h>
+#include <LibManual/Node.h>
+
+namespace Manual {
+
+class SectionNode : public Node {
+public:
+    virtual ~SectionNode() override = default;
+
+    SectionNode(StringView section, StringView name)
+        : m_section(MUST(String::from_utf8(section)))
+        , m_full_name(MUST(String::formatted("{}. {}", section, name)))
+    {
+    }
+
+    virtual NonnullRefPtrVector<Node>& children() const override
+    {
+        MUST(reify_if_needed());
+        return m_children;
+    }
+
+    virtual Node const* parent() const override { return nullptr; }
+    virtual String name() const override { return m_full_name; }
+    virtual bool is_open() const override { return m_open; }
+    void set_open(bool open);
+
+    String const& section_name() const { return m_section; }
+    ErrorOr<String> path() const;
+
+private:
+    ErrorOr<void> reify_if_needed() const;
+
+    String m_section;
+    String m_full_name;
+    mutable NonnullRefPtrVector<Node> m_children;
+    mutable bool m_reified { false };
+    bool m_open { false };
+};
+
+constexpr size_t number_of_sections = 8;
+
+extern Array<NonnullRefPtr<SectionNode>, number_of_sections> const sections;
+
+constexpr Array<StringView, number_of_sections> const section_numbers = {
+    "1"sv,
+    "2"sv,
+    "3"sv,
+    "4"sv,
+    "5"sv,
+    "6"sv,
+    "7"sv,
+    "8"sv,
+};
+
+}