AK: Use an enum to specify the open mode instead of a bool

Let's replace this bool with an `enum class` in order to enhance
readability. This is done by repurposing `MappedFile`'s `OpenMode` into
a shared `enum` simply called `Mode`.

AK/MemoryStream.cpp

@@ -12,9 +12,9 @@
 
 namespace AK {
 
-FixedMemoryStream::FixedMemoryStream(Bytes bytes, bool writing_enabled)
+FixedMemoryStream::FixedMemoryStream(Bytes bytes, Mode mode)
     : m_bytes(bytes)
-    , m_writing_enabled(writing_enabled)
+    , m_writing_enabled(mode == Mode::ReadWrite)
 {
 }
 

AK/MemoryStream.h

@@ -18,7 +18,12 @@ namespace AK {
 /// using a single read/write head.
 class FixedMemoryStream : public SeekableStream {
 public:
-    explicit FixedMemoryStream(Bytes bytes, bool writing_enabled = true);
+    enum class Mode {
+        ReadOnly,
+        ReadWrite,
+    };
+
+    explicit FixedMemoryStream(Bytes bytes, Mode mode = Mode::ReadWrite);
     explicit FixedMemoryStream(ReadonlyBytes bytes);
 
     virtual bool is_eof() const override;

Tests/AK/TestMemoryStream.cpp

@@ -259,7 +259,7 @@ TEST_CASE(fixed_memory_read_in_place)
     EXPECT_EQ(characters, some_words.bytes());
     EXPECT(readonly_stream.is_eof());
 
-    FixedMemoryStream mutable_stream { Bytes { const_cast<u8*>(some_words.bytes().data()), some_words.bytes().size() }, true };
+    FixedMemoryStream mutable_stream { Bytes { const_cast<u8*>(some_words.bytes().data()), some_words.bytes().size() }, FixedMemoryStream::Mode::ReadWrite };
     // Trying to read mutable values from a mutable stream should succeed.
     TRY_OR_FAIL(mutable_stream.read_in_place<u8>(1));
     EXPECT_EQ(mutable_stream.offset(), 1u);

Tests/LibCore/TestLibCoreMappedFile.cpp

@@ -27,7 +27,7 @@ TEST_CASE(mapped_file_open)
         TRY_OR_FAIL(maybe_file.value()->write_until_depleted(text.bytes()));
     }
 
-    auto maybe_file = Core::MappedFile::map("/tmp/file-open-test.txt"sv, Core::MappedFile::OpenMode::ReadWrite);
+    auto maybe_file = Core::MappedFile::map("/tmp/file-open-test.txt"sv, Core::MappedFile::Mode::ReadWrite);
     if (maybe_file.is_error()) {
         warnln("Failed to open the file: {}", strerror(maybe_file.error().code()));
         VERIFY_NOT_REACHED();
@@ -46,7 +46,7 @@ constexpr auto expected_buffer_contents = "<small>(Please consider transla
 
 TEST_CASE(mapped_file_read_bytes)
 {
-    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/long_lines.txt"sv, Core::MappedFile::OpenMode::ReadOnly));
+    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/long_lines.txt"sv, Core::MappedFile::Mode::ReadOnly));
 
     auto buffer = TRY_OR_FAIL(ByteBuffer::create_uninitialized(131));
 
@@ -63,7 +63,7 @@ constexpr auto expected_seek_contents3 = "levels of advanc"sv;
 
 TEST_CASE(mapped_file_seeking_around)
 {
-    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/long_lines.txt"sv, Core::MappedFile::OpenMode::ReadOnly));
+    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/long_lines.txt"sv, Core::MappedFile::Mode::ReadOnly));
 
     EXPECT_EQ(file->size().release_value(), 8702ul);
 
@@ -89,7 +89,7 @@ TEST_CASE(mapped_file_seeking_around)
 
 BENCHMARK_CASE(file_tell)
 {
-    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/10kb.txt"sv, Core::MappedFile::OpenMode::ReadOnly));
+    auto file = TRY_OR_FAIL(Core::MappedFile::map("/usr/Tests/LibCore/10kb.txt"sv, Core::MappedFile::Mode::ReadOnly));
     auto expected_file_offset = 0u;
     auto ten_byte_buffer = TRY_OR_FAIL(ByteBuffer::create_uninitialized(1));
     for (auto i = 0u; i < 4000; ++i) {

Userland/Libraries/LibAudio/Loader.cpp

@@ -44,7 +44,7 @@ static constexpr LoaderPluginInitializer s_initializers[] = {
 
 ErrorOr<NonnullRefPtr<Loader>, LoaderError> Loader::create(StringView path)
 {
-    auto stream = TRY(Core::MappedFile::map(path, Core::MappedFile::OpenMode::ReadOnly));
+    auto stream = TRY(Core::MappedFile::map(path, Core::MappedFile::Mode::ReadOnly));
     return adopt_ref(*new (nothrow) Loader(TRY(Loader::create_plugin(move(stream)))));
 }
 

Userland/Libraries/LibCore/MappedFile.cpp

@@ -15,9 +15,9 @@
 
 namespace Core {
 
-ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map(StringView path, OpenMode mode)
+ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map(StringView path, Mode mode)
 {
-    auto const file_mode = mode == OpenMode::ReadOnly ? O_RDONLY : O_RDWR;
+    auto const file_mode = mode == Mode::ReadOnly ? O_RDONLY : O_RDWR;
     auto fd = TRY(Core::System::open(path, file_mode | O_CLOEXEC, 0));
     return map_from_fd_and_close(fd, path, mode);
 }
@@ -27,7 +27,7 @@ ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map_from_file(NonnullOwnPtr<Core:
     return map_from_fd_and_close(stream->leak_fd(Badge<MappedFile> {}), path);
 }
 
-ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map_from_fd_and_close(int fd, [[maybe_unused]] StringView path, OpenMode mode)
+ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map_from_fd_and_close(int fd, [[maybe_unused]] StringView path, Mode mode)
 {
     TRY(Core::System::fcntl(fd, F_SETFD, FD_CLOEXEC));
 
@@ -41,11 +41,11 @@ ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map_from_fd_and_close(int fd, [[m
     int protection;
     int flags;
     switch (mode) {
-    case OpenMode::ReadOnly:
+    case Mode::ReadOnly:
         protection = PROT_READ;
         flags = MAP_SHARED;
         break;
-    case OpenMode::ReadWrite:
+    case Mode::ReadWrite:
         protection = PROT_READ | PROT_WRITE;
         // Don't map a read-write mapping shared as a precaution.
         flags = MAP_PRIVATE;
@@ -57,8 +57,8 @@ ErrorOr<NonnullOwnPtr<MappedFile>> MappedFile::map_from_fd_and_close(int fd, [[m
     return adopt_own(*new MappedFile(ptr, size, mode));
 }
 
-MappedFile::MappedFile(void* ptr, size_t size, OpenMode mode)
+MappedFile::MappedFile(void* ptr, size_t size, Mode mode)
-    : FixedMemoryStream(Bytes { ptr, size }, mode == OpenMode::ReadWrite)
+    : FixedMemoryStream(Bytes { ptr, size }, mode)
     , m_data(ptr)
     , m_size(size)
 {

Userland/Libraries/LibCore/MappedFile.h

@@ -22,15 +22,9 @@ class MappedFile : public FixedMemoryStream {
     AK_MAKE_NONMOVABLE(MappedFile);
 
 public:
-    // Reflects a simplified version of mmap protection and flags.
+    static ErrorOr<NonnullOwnPtr<MappedFile>> map(StringView path, Mode mode = Mode::ReadOnly);
-    enum class OpenMode {
-        ReadOnly,
-        ReadWrite,
-    };
-
-    static ErrorOr<NonnullOwnPtr<MappedFile>> map(StringView path, OpenMode mode = OpenMode::ReadOnly);
     static ErrorOr<NonnullOwnPtr<MappedFile>> map_from_file(NonnullOwnPtr<Core::File>, StringView path);
-    static ErrorOr<NonnullOwnPtr<MappedFile>> map_from_fd_and_close(int fd, StringView path, OpenMode mode = OpenMode::ReadOnly);
+    static ErrorOr<NonnullOwnPtr<MappedFile>> map_from_fd_and_close(int fd, StringView path, Mode mode = Mode::ReadOnly);
     virtual ~MappedFile();
 
     // Non-stream APIs for using MappedFile as a simple POSIX API wrapper.
@@ -39,7 +33,7 @@ public:
     ReadonlyBytes bytes() const { return { m_data, m_size }; }
 
 private:
-    explicit MappedFile(void*, size_t, OpenMode);
+    explicit MappedFile(void*, size_t, Mode);
 
     void* m_data { nullptr };
     size_t m_size { 0 };