LibCore: Remove `Stream::is_{readable,writable}`

Next to functions like `is_eof` these were really confusing to use, and
the `read`/`write` functions should fail anyways if a stream is not
readable/writable.

Meta/Lagom/Wasm/js_repl.cpp

@@ -65,7 +65,6 @@ void displayln() { user_display("\n", 1); }
 
 class UserDisplayStream final : public Core::Stream::Stream {
     virtual ErrorOr<Bytes> read(Bytes) override { return Error::from_string_view("Not readable"sv); };
-    virtual bool is_writable() const override { return true; }
     virtual ErrorOr<size_t> write(ReadonlyBytes bytes) override
     {
         user_display(bit_cast<char const*>(bytes.data()), bytes.size());

Tests/LibCore/TestLibCoreStream.cpp

@@ -29,8 +29,6 @@ TEST_CASE(file_open)
     // Testing out some basic file properties.
     auto file = maybe_file.release_value();
     EXPECT(file->is_open());
-    EXPECT(!file->is_readable());
-    EXPECT(file->is_writable());
     EXPECT(!file->is_eof());
 
     auto maybe_size = file->size();

Userland/Libraries/LibCompress/Brotli.h

@@ -107,9 +107,7 @@ public:
 public:
     BrotliDecompressionStream(Stream&);
 
-    bool is_readable() const override { return m_input_stream.is_readable(); }
     ErrorOr<Bytes> read(Bytes output_buffer) override;
-    bool is_writable() const override { return m_input_stream.is_writable(); }
     ErrorOr<size_t> write(ReadonlyBytes bytes) override { return m_input_stream.write(bytes); }
     bool is_eof() const override;
     bool is_open() const override { return m_input_stream.is_open(); }

Userland/Libraries/LibCore/InputBitStream.h

@@ -30,7 +30,6 @@ public:
     }
 
     // ^Stream
-    virtual bool is_readable() const override { return m_stream.is_readable(); }
     virtual ErrorOr<Bytes> read(Bytes bytes) override
     {
         if (m_current_byte.has_value() && is_aligned_to_byte_boundary()) {
@@ -40,7 +39,6 @@ public:
         align_to_byte_boundary();
         return m_stream.read(bytes);
     }
-    virtual bool is_writable() const override { return m_stream.is_writable(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes bytes) override { return m_stream.write(bytes); }
     virtual bool write_or_error(ReadonlyBytes bytes) override { return m_stream.write_or_error(bytes); }
     virtual bool is_eof() const override { return m_stream.is_eof() && !m_current_byte.has_value(); }
@@ -147,7 +145,6 @@ public:
     }
 
     // ^Stream
-    virtual bool is_readable() const override { return m_stream.is_readable(); }
     virtual ErrorOr<Bytes> read(Bytes bytes) override
     {
         if (m_current_byte.has_value() && is_aligned_to_byte_boundary()) {
@@ -157,7 +154,6 @@ public:
         align_to_byte_boundary();
         return m_stream.read(bytes);
     }
-    virtual bool is_writable() const override { return m_stream.is_writable(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes bytes) override { return m_stream.write(bytes); }
     virtual bool write_or_error(ReadonlyBytes bytes) override { return m_stream.write_or_error(bytes); }
     virtual bool is_eof() const override { return m_stream.is_eof() && !m_current_byte.has_value(); }

Userland/Libraries/LibCore/Stream.cpp

@@ -229,9 +229,6 @@ ErrorOr<void> File::open_path(StringView filename, mode_t permissions)
     return {};
 }
 
-bool File::is_readable() const { return has_flag(m_mode, OpenMode::Read); }
-bool File::is_writable() const { return has_flag(m_mode, OpenMode::Write); }
-
 ErrorOr<Bytes> File::read(Bytes buffer)
 {
     if (!has_flag(m_mode, OpenMode::Read)) {

Userland/Libraries/LibCore/Stream.h

@@ -28,7 +28,6 @@ namespace Core::Stream {
 /// operations one can perform on every stream in LibCore.
 class Stream {
 public:
-    virtual bool is_readable() const { return false; }
     /// Reads into a buffer, with the maximum size being the size of the buffer.
     /// The amount of bytes read can be smaller than the size of the buffer.
     /// Returns either the bytes that were read, or an errno in the case of
@@ -46,7 +45,6 @@ public:
     /// internal stack-based buffer.
     virtual ErrorOr<void> discard(size_t discarded_bytes);
 
-    virtual bool is_writable() const { return false; }
     /// Tries to write the entire contents of the buffer. It is possible for
     /// less than the full buffer to be written. Returns either the amount of
     /// bytes written into the stream, or an errno in the case of failure.
@@ -239,10 +237,8 @@ public:
         return *this;
     }
 
-    virtual bool is_readable() const override;
     virtual ErrorOr<Bytes> read(Bytes) override;
     virtual ErrorOr<ByteBuffer> read_all(size_t block_size = 4096) override;
-    virtual bool is_writable() const override;
     virtual ErrorOr<size_t> write(ReadonlyBytes) override;
     virtual bool is_eof() const override;
     virtual bool is_open() const override;
@@ -346,8 +342,6 @@ public:
         return *this;
     }
 
-    virtual bool is_readable() const override { return is_open(); }
-    virtual bool is_writable() const override { return is_open(); }
     virtual ErrorOr<Bytes> read(Bytes buffer) override { return m_helper.read(buffer, default_flags()); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_helper.write(buffer, default_flags()); }
     virtual bool is_eof() const override { return m_helper.is_eof(); }
@@ -423,8 +417,6 @@ public:
         return m_helper.read(buffer, default_flags());
     }
 
-    virtual bool is_readable() const override { return is_open(); }
-    virtual bool is_writable() const override { return is_open(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_helper.write(buffer, default_flags()); }
     virtual bool is_eof() const override { return m_helper.is_eof(); }
     virtual bool is_open() const override { return m_helper.is_open(); }
@@ -484,8 +476,6 @@ public:
         return *this;
     }
 
-    virtual bool is_readable() const override { return is_open(); }
-    virtual bool is_writable() const override { return is_open(); }
     virtual ErrorOr<Bytes> read(Bytes buffer) override { return m_helper.read(buffer, default_flags()); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_helper.write(buffer, default_flags()); }
     virtual bool is_eof() const override { return m_helper.is_eof(); }
@@ -717,7 +707,7 @@ public:
         if (m_buffer.span().slice(0, m_buffered_size).contains_slow('\n'))
             return true;
 
-        if (!stream().is_readable())
+        if (stream().is_eof())
             return false;
 
         while (m_buffered_size < m_buffer.size()) {
@@ -818,9 +808,7 @@ public:
     BufferedSeekable(BufferedSeekable&& other) = default;
     BufferedSeekable& operator=(BufferedSeekable&& other) = default;
 
-    virtual bool is_readable() const override { return m_helper.stream().is_readable(); }
     virtual ErrorOr<Bytes> read(Bytes buffer) override { return m_helper.read(move(buffer)); }
-    virtual bool is_writable() const override { return m_helper.stream().is_writable(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_helper.stream().write(buffer); }
     virtual bool is_eof() const override { return m_helper.is_eof(); }
     virtual bool is_open() const override { return m_helper.stream().is_open(); }
@@ -889,9 +877,7 @@ public:
         return *this;
     }
 
-    virtual bool is_readable() const override { return m_helper.stream().is_readable(); }
     virtual ErrorOr<Bytes> read(Bytes buffer) override { return m_helper.read(move(buffer)); }
-    virtual bool is_writable() const override { return m_helper.stream().is_writable(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_helper.stream().write(buffer); }
     virtual bool is_eof() const override { return m_helper.is_eof(); }
     virtual bool is_open() const override { return m_helper.stream().is_open(); }
@@ -977,9 +963,7 @@ public:
         return {};
     }
 
-    virtual bool is_readable() const override { return m_socket.is_readable(); }
     virtual ErrorOr<Bytes> read(Bytes buffer) override { return m_socket.read(move(buffer)); }
-    virtual bool is_writable() const override { return m_socket.is_writable(); }
     virtual ErrorOr<size_t> write(ReadonlyBytes buffer) override { return m_socket.write(buffer); }
     virtual bool is_eof() const override { return m_socket.is_eof(); }
     virtual bool is_open() const override { return m_socket.is_open(); }

Userland/Libraries/LibTLS/TLSv12.h

@@ -356,9 +356,6 @@ private:
     }
 
 public:
-    virtual bool is_readable() const override { return true; }
-    virtual bool is_writable() const override { return true; }
-
     /// Reads into a buffer, with the maximum size being the size of the buffer.
     /// The amount of bytes read can be smaller than the size of the buffer.
     /// Returns either the bytes that were read, or an errno in the case of