Implemented tcp sockets (only IPv4) and asynchronous IO (for sockets).

SModule

@@ -10,6 +10,7 @@ mijin_sources = Split("""
     source/mijin/debug/symbol_info.cpp
     source/mijin/io/process.cpp
     source/mijin/io/stream.cpp
+    source/mijin/net/socket.cpp
     source/mijin/util/os.cpp
     source/mijin/types/name.cpp
     source/mijin/virtual_filesystem/filesystem.cpp

source/mijin/io/process.cpp

@@ -53,7 +53,7 @@ int ProcessStream::close()
     return result;
 }
 
-StreamError ProcessStream::readRaw(std::span<std::uint8_t> buffer, bool partial, std::size_t* outBytesRead)
+StreamError ProcessStream::readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
 {
     assert(handle);
     assert(mode == FileOpenMode::READ || mode == FileOpenMode::READ_WRITE);
@@ -67,7 +67,7 @@ StreamError ProcessStream::readRaw(std::span<std::uint8_t> buffer, bool partial,
     if (std::ferror(handle)) {
         return StreamError::IO_ERROR;
     }
-    if (!partial && readBytes < buffer.size()) {
+    if (!options.partial && readBytes < buffer.size()) {
         return StreamError::IO_ERROR;
     }
     if (outBytesRead != nullptr)
@@ -134,7 +134,10 @@ StreamFeatures ProcessStream::getFeatures()
             .read = (mode == FileOpenMode::READ),
             .write = (mode == FileOpenMode::WRITE || mode == FileOpenMode::READ_WRITE),
             .tell = true,
-            .seek = false
+            .seek = false,
+            .readOptions = {
+                .partial = true
+            }
         };
     }
     return {};

source/mijin/io/process.hpp

@@ -26,7 +26,7 @@ public:
     [[nodiscard]] inline bool isOpen() const { return handle != nullptr; }
 
     // Stream overrides
-    StreamError readRaw(std::span<std::uint8_t> buffer, bool partial = false, std::size_t* outBytesRead = nullptr) override;
+    StreamError readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr) override;
     StreamError writeRaw(std::span<const std::uint8_t> buffer) override;
     std::size_t tell() override;
     StreamError seek(std::intptr_t pos, SeekMode seekMode = SeekMode::ABSOLUTE) override;

source/mijin/io/stream.cpp

@@ -35,6 +35,24 @@ namespace mijin
 
 void Stream::flush() {}
 
+mijin::Task<StreamError> Stream::c_readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
+{
+    (void) buffer;
+    (void) options;
+    (void) outBytesRead;
+
+    MIJIN_ASSERT(!getFeatures().async || !getFeatures().read, "Stream advertises async read, but doesn't implement it.");
+    co_return StreamError::NOT_SUPPORTED;
+}
+
+mijin::Task<StreamError> Stream::c_writeRaw(std::span<const std::uint8_t> buffer)
+{
+    (void) buffer;
+
+    MIJIN_ASSERT(!getFeatures().async || !getFeatures().write, "Stream advertises async write, but doesn't implement it.");
+    co_return StreamError::NOT_SUPPORTED;
+}
+
 StreamError Stream::readBinaryString(std::string& outString)
 {
     std::uint32_t length; // NOLINT(cppcoreguidelines-init-variables)
@@ -55,7 +73,7 @@ StreamError Stream::readBinaryString(std::string& outString)
 
 StreamError Stream::writeBinaryString(std::string_view str)
 {
-    assert(str.length() <= std::numeric_limits<std::uint32_t>::max());
+    MIJIN_ASSERT(str.length() <= std::numeric_limits<std::uint32_t>::max(), "Binary string is too long.");
     const std::uint32_t length = static_cast<std::uint32_t>(str.length());
     StreamError error = write(length);
     if (error != StreamError::SUCCESS) {
@@ -64,6 +82,35 @@ StreamError Stream::writeBinaryString(std::string_view str)
     return writeSpan(str.begin(), str.end());
 }
 
+mijin::Task<StreamError> Stream::c_readBinaryString(std::string& outString)
+{
+    std::uint32_t length; // NOLINT(cppcoreguidelines-init-variables)
+    StreamError error = co_await c_read(length);
+    if (error != StreamError::SUCCESS) {
+        co_return error;
+    }
+
+    std::string result;
+    result.resize(length);
+    error = co_await c_readSpan(result.begin(), result.end());
+    if (error != StreamError::SUCCESS) {
+        co_return error;
+    }
+    outString = std::move(result);
+    co_return StreamError::SUCCESS;
+}
+
+mijin::Task<StreamError> Stream::c_writeBinaryString(std::string_view str)
+{
+    MIJIN_ASSERT(str.length() <= std::numeric_limits<std::uint32_t>::max(), "Binary string is too long.");
+    const std::uint32_t length = static_cast<std::uint32_t>(str.length());
+    StreamError error = co_await c_write(length);
+    if (error != StreamError::SUCCESS) {
+        co_return error;
+    }
+    co_return co_await c_writeSpan(str.begin(), str.end());
+}
+
 StreamError Stream::getTotalLength(std::size_t& outLength)
 {
     const StreamFeatures features = getFeatures();
@@ -106,7 +153,7 @@ StreamError Stream::readRest(TypelessBuffer& outBuffer)
     while (!isAtEnd())
     {
         std::size_t bytesRead = 0;
-        if (StreamError error = readRaw(chunk, true, &bytesRead); error != StreamError::SUCCESS)
+        if (StreamError error = readRaw(chunk, {.partial = true}, &bytesRead); error != StreamError::SUCCESS)
         {
             return error;
         }
@@ -118,6 +165,129 @@ StreamError Stream::readRest(TypelessBuffer& outBuffer)
     return StreamError::SUCCESS;
 }
 
+mijin::Task<StreamError> Stream::c_readRest(TypelessBuffer& outBuffer)
+{
+    // first try to allocate everything at once
+    std::size_t length = 0;
+    if (StreamError lengthError = getTotalLength(length); lengthError == StreamError::SUCCESS)
+    {
+        MIJIN_ASSERT(getFeatures().tell, "How did you find the length if you cannot tell()?");
+        length -= tell();
+        outBuffer.resize(length);
+        if (StreamError error = co_await c_readRaw(outBuffer.data(), length); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+        co_return StreamError::SUCCESS;
+    }
+
+    // could not determine the size, read chunk-wise
+    static constexpr std::size_t CHUNK_SIZE = 4096;
+    std::array<std::byte, CHUNK_SIZE> chunk = {};
+
+    while (!isAtEnd())
+    {
+        std::size_t bytesRead = 0;
+        if (StreamError error = co_await c_readRaw(chunk, {.partial = true}, &bytesRead); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+
+        outBuffer.resize(outBuffer.byteSize() + bytesRead);
+        std::span<std::byte> bufferBytes = outBuffer.makeSpan<std::byte>();
+        std::copy_n(chunk.begin(), bytesRead, bufferBytes.end() - static_cast<long>(bytesRead));
+    }
+    co_return StreamError::SUCCESS;
+}
+
+StreamError Stream::readLine(std::string& outString)
+{
+    MIJIN_ASSERT(getFeatures().readOptions.peek, "Stream needs to support peeking.");
+
+    static constexpr std::size_t BUFFER_SIZE = 4096;
+    std::array<char, BUFFER_SIZE> buffer;
+
+    outString.clear();
+    bool done = false;
+    while(!done)
+    {
+        // read into the buffer
+        std::size_t bytesRead = 0;
+        if (StreamError error = readRaw(buffer, {.partial = true, .peek = true}, &bytesRead); error != StreamError::SUCCESS)
+        {
+            return error;
+        }
+        // try to find a \n
+        auto begin = buffer.begin();
+        auto end = buffer.begin() + bytesRead;
+        auto newline = std::find(begin, end, '\n');
+
+        if (newline != end)
+        {
+            // found the end
+            outString.append(begin, newline);
+            end = newline + 1;
+            done = true;
+        }
+        else
+        {
+            outString.append(begin, end);
+        }
+
+        // read again, this time to skip
+        if (StreamError error = readSpan(begin, end); error != StreamError::SUCCESS)
+        {
+            return error;
+        }
+    }
+
+    return StreamError::SUCCESS;
+}
+
+mijin::Task<StreamError> Stream::c_readLine(std::string& outString)
+{
+    MIJIN_ASSERT(getFeatures().readOptions.peek, "Stream needs to support peeking.");
+
+    static constexpr std::size_t BUFFER_SIZE = 4096;
+    std::array<char, BUFFER_SIZE> buffer;
+
+    outString.clear();
+    bool done = false;
+    while(!done)
+    {
+        // read into the buffer
+        std::size_t bytesRead = 0;
+        if (StreamError error = co_await c_readRaw(buffer, {.partial = true, .peek = true}, &bytesRead); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+        // try to find a \n
+        auto begin = buffer.begin();
+        auto end = buffer.begin() + bytesRead;
+        auto newline = std::find(begin, end, '\n');
+
+        if (newline != end)
+        {
+            // found the end
+            outString.append(begin, newline);
+            end = newline + 1;
+            done = true;
+        }
+        else
+        {
+            outString.append(begin, end);
+        }
+
+        // read again, this time to skip
+        if (StreamError error = co_await c_readSpan(begin, end); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+    }
+
+    co_return StreamError::SUCCESS;
+}
+
 FileStream::~FileStream()
 {
     if (handle) {
@@ -172,7 +342,7 @@ void FileStream::close()
     assert(result == 0);
 }
 
-StreamError FileStream::readRaw(std::span<std::uint8_t> buffer, bool partial, std::size_t* outBytesRead)
+StreamError FileStream::readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
 {
     assert(handle);
     assert(mode == FileOpenMode::READ || mode == FileOpenMode::READ_WRITE);
@@ -181,12 +351,19 @@ StreamError FileStream::readRaw(std::span<std::uint8_t> buffer, bool partial, st
     if (std::ferror(handle)) {
         return StreamError::IO_ERROR;
     }
-    if (!partial && readBytes < buffer.size()) {
+    if (!options.partial && readBytes < buffer.size()) {
         return StreamError::IO_ERROR;
     }
     if (outBytesRead != nullptr) {
         *outBytesRead = readBytes;
     }
+    if (options.peek)
+    {
+        if (StreamError error = seek(-static_cast<std::intptr_t>(readBytes), SeekMode::RELATIVE); error != StreamError::SUCCESS)
+        {
+            return error;
+        }
+    }
     return StreamError::SUCCESS;
 }
 
@@ -265,7 +442,11 @@ StreamFeatures FileStream::getFeatures()
             .read = (mode == FileOpenMode::READ),
             .write = (mode == FileOpenMode::WRITE || mode == FileOpenMode::APPEND || mode == FileOpenMode::READ_WRITE),
             .tell = true,
-            .seek = true
+            .seek = true,
+            .readOptions = {
+                .partial = true,
+                .peek = true
+            }
         };
     }
     return {};
@@ -293,10 +474,10 @@ void MemoryStream::close()
     data_ = {};
 }
 
-StreamError MemoryStream::readRaw(std::span<std::uint8_t> buffer, bool partial, std::size_t* outBytesRead)
+StreamError MemoryStream::readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
 {
     assert(isOpen());
-    if (!partial && availableBytes() < buffer.size()) {
+    if (!options.partial && availableBytes() < buffer.size()) {
         return StreamError::IO_ERROR; // TODO: need more errors?
     }
     const std::size_t numBytes = std::min(buffer.size(), availableBytes());
@@ -304,7 +485,9 @@ StreamError MemoryStream::readRaw(std::span<std::uint8_t> buffer, bool partial,
     if (outBytesRead) {
         *outBytesRead = numBytes;
     }
+    if (!options.peek) {
         pos_ += numBytes;
+    }
     return StreamError::SUCCESS;
 }
 
@@ -362,7 +545,10 @@ StreamFeatures MemoryStream::getFeatures()
         .read  = true,
         .write = canWrite_,
         .tell  = true,
-        .seek  = true
+        .seek  = true,
+        .readOptions = {
+            .peek = true
+        }
     };
 }
 

source/mijin/io/stream.hpp

@@ -11,7 +11,9 @@
 #include <span>
 #include <stdexcept>
 #include <string>
+#include "../async/coroutine.hpp"
 #include "../container/typeless_buffer.hpp"
+#include "../types/result.hpp"
 #include "../util/exception.hpp"
 
 namespace mijin
@@ -36,12 +38,21 @@ enum class SeekMode
     RELATIVE_TO_END
 };
 
+struct ReadOptions
+{
+    bool partial : 1 = false;
+    bool peek    : 1 = false;
+};
+
 struct StreamFeatures
 {
     bool read  : 1 = false;
     bool write : 1 = false;
     bool tell  : 1 = false;
     bool seek  : 1 = false;
+    bool async : 1 = false;
+
+    ReadOptions readOptions = {};
 };
 
 enum class FileOpenMode
@@ -54,10 +65,11 @@ enum class FileOpenMode
 
 enum class [[nodiscard]] StreamError
 {
-    SUCCESS,
+    SUCCESS           = 0,
-    IO_ERROR,
+    IO_ERROR          = 1,
-    NOT_SUPPORTED,
+    NOT_SUPPORTED     = 2,
-    UNKNOWN_ERROR
+    CONNECTION_CLOSED = 3,
+    UNKNOWN_ERROR     = -1
 };
 
 class Stream
@@ -66,7 +78,12 @@ public:
     virtual ~Stream() = default;
     
 public:
-    virtual StreamError readRaw(std::span<std::uint8_t> buffer, bool partial = false, std::size_t* outBytesRead = nullptr) = 0;
+    virtual StreamError readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr) = 0;
+    [[deprecated("Partial parameter has been replaced with options.")]]
+    StreamError readRaw(std::span<std::uint8_t> buffer, bool partial, std::size_t* outBytesRead = nullptr)
+    {
+        return readRaw(buffer, {.partial = partial}, outBytesRead);
+    }
     virtual StreamError writeRaw(std::span<const std::uint8_t> buffer) = 0;
     virtual std::size_t tell() = 0;
     virtual StreamError seek(std::intptr_t pos, SeekMode seekMode = SeekMode::ABSOLUTE) = 0;
@@ -74,74 +91,163 @@ public:
     virtual bool isAtEnd() = 0;
     virtual StreamFeatures getFeatures() = 0;
 
-    inline StreamError readRaw(void* outData, std::size_t bytes, bool partial = false, std::size_t* outBytesRead = nullptr)
+    // async interface (requires getFeatures().async to be set)
+    virtual mijin::Task<StreamError> c_readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr);
+    virtual mijin::Task<StreamError> c_writeRaw(std::span<const std::uint8_t> buffer);
+
+    StreamError readRaw(void* outData, std::size_t bytes, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
     {
         std::uint8_t* ptr = static_cast<std::uint8_t*>(outData);
-        return readRaw(std::span(ptr, ptr + bytes), partial, outBytesRead);
+        return readRaw(std::span(ptr, ptr + bytes), options, outBytesRead);
+    }
+
+    [[deprecated("Partial parameter has been replaced with options.")]]
+    StreamError readRaw(void* outData, std::size_t bytes, bool partial, std::size_t* outBytesRead = nullptr)
+    {
+        std::uint8_t* ptr = static_cast<std::uint8_t*>(outData);
+        return readRaw(std::span(ptr, ptr + bytes), {.partial = partial}, outBytesRead);
+    }
+
+    mijin::Task<StreamError> c_readRaw(void* outData, std::size_t bytes, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
+    {
+        std::uint8_t* ptr = static_cast<std::uint8_t*>(outData);
+        return c_readRaw(std::span(ptr, ptr + bytes), options, outBytesRead);
     }
 
     template<std::ranges::contiguous_range TRange>
-    inline StreamError readRaw(TRange& range, bool partial = false, std::size_t* outBytesRead = nullptr)
+    StreamError readRaw(TRange& range, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
     {
         const std::size_t bytes = std::distance(range.begin(), range.end()) * sizeof(std::ranges::range_value_t<TRange>);
-        return readRaw(&*range.begin(), bytes, partial, outBytesRead);
+        return readRaw(&*range.begin(), bytes, options, outBytesRead);
     }
 
-    inline StreamError writeRaw(const void* data, std::size_t bytes)
+    template<std::ranges::contiguous_range TRange>
+    [[deprecated("Partial parameter has been replaced with options.")]]
+    StreamError readRaw(TRange& range, bool partial, std::size_t* outBytesRead = nullptr)
+    {
+        const std::size_t bytes = std::distance(range.begin(), range.end()) * sizeof(std::ranges::range_value_t<TRange>);
+        return readRaw(&*range.begin(), bytes, {.partial = partial}, outBytesRead);
+    }
+
+    template<std::ranges::contiguous_range TRange>
+    mijin::Task<StreamError> c_readRaw(TRange& range, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
+    {
+        const std::size_t bytes = std::distance(range.begin(), range.end()) * sizeof(std::ranges::range_value_t<TRange>);
+        return c_readRaw(&*range.begin(), bytes, options, outBytesRead);
+    }
+
+    StreamError writeRaw(const void* data, std::size_t bytes)
     {
         const std::uint8_t* ptr = static_cast<const std::uint8_t*>(data);
         return writeRaw(std::span(ptr, ptr + bytes));
     }
 
+    mijin::Task<StreamError> c_writeRaw(const void* data, std::size_t bytes)
+    {
+        const std::uint8_t* ptr = static_cast<const std::uint8_t*>(data);
+        return c_writeRaw(std::span(ptr, ptr + bytes));
+    }
+
     template<std::ranges::contiguous_range TRange>
-    inline StreamError writeRaw(const TRange& range)
+    StreamError writeRaw(const TRange& range)
     {
         const std::size_t bytes = std::distance(range.begin(), range.end()) * sizeof(std::ranges::range_value_t<TRange>);
         return writeRaw(&*range.begin(), bytes);
     }
 
-    template<typename T>
+    template<std::ranges::contiguous_range TRange>
-    inline StreamError read(T& value)
+    mijin::Task<StreamError> c_writeRaw(const TRange& range)
     {
-        return readRaw(&value, sizeof(T));
+        const std::size_t bytes = std::distance(range.begin(), range.end()) * sizeof(std::ranges::range_value_t<TRange>);
+        return c_writeRaw(&*range.begin(), bytes);
     }
 
     template<typename T>
-    inline StreamError readSpan(T& values)
+    StreamError read(T& value, const ReadOptions& options = {})
+    {
+        MIJIN_ASSERT(!options.partial, "Cannot partially read a value.");
+        return readRaw(&value, sizeof(T), options);
+    }
+
+    template<typename T>
+    mijin::Task<StreamError> c_read(T& value, const ReadOptions& options = {})
+    {
+        MIJIN_ASSERT(!options.partial, "Cannot partially read a value.");
+        return c_readRaw(&value, sizeof(T), options);
+    }
+
+    template<typename T>
+    StreamError readSpan(T& values, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
     {
         auto asSpan = std::span(values);
-        return readRaw(asSpan.data(), asSpan.size_bytes());
+        return readRaw(asSpan.data(), asSpan.size_bytes(), options, outBytesRead);
+    }
+
+    template<typename T>
+    mijin::Task<StreamError> c_readSpan(T& values, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
+    {
+        auto asSpan = std::span(values);
+        return c_readRaw(asSpan.data(), asSpan.size_bytes(), options, outBytesRead);
     }
 
     template<typename TItBegin, typename TItEnd>
-    inline StreamError readSpan(TItBegin&& begin, TItEnd&& end)
+    StreamError readSpan(TItBegin&& begin, TItEnd&& end, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
     {
         auto asSpan = std::span(std::forward<TItBegin>(begin), std::forward<TItEnd>(end));
-        return readRaw(asSpan.data(), asSpan.size_bytes());
+        return readRaw(asSpan.data(), asSpan.size_bytes(), options, outBytesRead);
+    }
+
+    template<typename TItBegin, typename TItEnd>
+    mijin::Task<StreamError> c_readSpan(TItBegin&& begin, TItEnd&& end, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr)
+    {
+        auto asSpan = std::span(std::forward<TItBegin>(begin), std::forward<TItEnd>(end));
+        return c_readRaw(asSpan.data(), asSpan.size_bytes(), options, outBytesRead);
     }
 
     template<typename T>
-    inline StreamError write(const T& value)
+    StreamError write(const T& value) requires(std::is_trivial_v<T>)
     {
         return writeRaw(&value, sizeof(T));
     }
 
     template<typename T>
-    inline StreamError writeSpan(const T& values)
+    mijin::Task<StreamError> c_write(const T& value) requires(std::is_trivial_v<T>)
+    {
+        return c_writeRaw(&value, sizeof(T));
+    }
+
+    template<typename T>
+    StreamError writeSpan(const T& values)
     {
         auto asSpan = std::span(values);
         return writeRaw(asSpan.data(), asSpan.size_bytes());
     }
 
+    template<typename T>
+    mijin::Task<StreamError> c_writeSpan(const T& values)
+    {
+        auto asSpan = std::span(values);
+        return c_writeRaw(asSpan.data(), asSpan.size_bytes());
+    }
+
     template<typename TItBegin, typename TItEnd>
-    inline StreamError writeSpan(TItBegin&& begin, TItEnd&& end)
+    StreamError writeSpan(TItBegin&& begin, TItEnd&& end)
     {
         return writeSpan(std::span(std::forward<TItBegin>(begin), std::forward<TItEnd>(end)));
     }
 
+    template<typename TItBegin, typename TItEnd>
+    mijin::Task<StreamError> c_writeSpan(TItBegin&& begin, TItEnd&& end)
+    {
+        return c_writeSpan(std::span(std::forward<TItBegin>(begin), std::forward<TItEnd>(end)));
+    }
+
     StreamError readBinaryString(std::string& outString);
     StreamError writeBinaryString(std::string_view str);
 
+    mijin::Task<StreamError> c_readBinaryString(std::string& outString);
+    mijin::Task<StreamError> c_writeBinaryString(std::string_view str);
+
     [[deprecated("Use readBinaryString() or readAsString() instead.")]]
     inline StreamError readString(std::string& outString) { return readBinaryString(outString); }
 
@@ -150,14 +256,26 @@ public:
 
     StreamError getTotalLength(std::size_t& outLength);
     StreamError readRest(TypelessBuffer& outBuffer);
+    mijin::Task<StreamError> c_readRest(TypelessBuffer& outBuffer);
+
+    StreamError readLine(std::string& outString);
+    mijin::Task<StreamError> c_readLine(std::string& outString);
 
     template<typename TChar = char>
     StreamError readAsString(std::basic_string<TChar>& outString);
 
-    inline StreamError writeText(std::string_view str)
+    template<typename TChar = char>
+    mijin::Task<StreamError> c_readAsString(std::basic_string<TChar>& outString);
+
+    StreamError writeText(std::string_view str)
     {
         return writeSpan(str);
     }
+
+    mijin::Task<StreamError> c_writeText(std::string_view str)
+    {
+        return c_writeSpan(str);
+    }
 };
 
 class FileStream : public Stream
@@ -177,7 +295,7 @@ public:
     [[nodiscard]] inline bool isOpen() const { return handle != nullptr; }
 
     // Stream overrides
-    StreamError readRaw(std::span<std::uint8_t> buffer, bool partial = false, std::size_t* outBytesRead = nullptr) override;
+    StreamError readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr) override;
     StreamError writeRaw(std::span<const std::uint8_t> buffer) override;
     std::size_t tell() override;
     StreamError seek(std::intptr_t pos, SeekMode seekMode = SeekMode::ABSOLUTE) override;
@@ -210,7 +328,7 @@ public:
     }
 
     // Stream overrides
-    StreamError readRaw(std::span<std::uint8_t> buffer, bool partial = false, std::size_t* outBytesRead = nullptr) override;
+    StreamError readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options = {}, std::size_t* outBytesRead = nullptr) override;
     StreamError writeRaw(std::span<const std::uint8_t> buffer) override;
     std::size_t tell() override;
     StreamError seek(std::intptr_t pos, SeekMode seekMode = SeekMode::ABSOLUTE) override;
@@ -220,6 +338,9 @@ private:
     void openROImpl(const void* data, std::size_t bytes);
 };
 
+template<typename TSuccess>
+using StreamResult = ResultBase<TSuccess, StreamError>;
+
 //
 // public functions
 //
@@ -251,7 +372,7 @@ StreamError Stream::readAsString(std::basic_string<TChar>& outString)
     while (!isAtEnd())
     {
         std::size_t bytesRead = 0;
-        if (StreamError error = readRaw(chunk, true, &bytesRead); error != StreamError::SUCCESS)
+        if (StreamError error = readRaw(chunk, {.partial = true}, &bytesRead); error != StreamError::SUCCESS)
         {
             return error;
         }
@@ -260,6 +381,42 @@ StreamError Stream::readAsString(std::basic_string<TChar>& outString)
     return StreamError::SUCCESS;
 }
 
+template<typename TChar>
+mijin::Task<StreamError> Stream::c_readAsString(std::basic_string<TChar>& outString)
+{
+    static_assert(sizeof(TChar) == 1, "Can only read to 8-bit character types (char, unsigned char or char8_t");
+
+    // first try to allocate everything at once
+    std::size_t length = 0;
+    if (StreamError lengthError = getTotalLength(length); lengthError == StreamError::SUCCESS)
+    {
+        MIJIN_ASSERT(getFeatures().tell, "How did you find the length if you cannot tell()?");
+        length -= tell();
+        outString.resize(length);
+        if (StreamError error = co_await c_readRaw(outString.data(), length); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+        co_return StreamError::SUCCESS;
+    }
+
+    // could not determine the size, read chunk-wise
+    static constexpr std::size_t CHUNK_SIZE = 4096;
+    std::array<TChar, CHUNK_SIZE> chunk;
+
+    outString.clear();
+    while (!isAtEnd())
+    {
+        std::size_t bytesRead = 0;
+        if (StreamError error = co_await c_readRaw(chunk, true, &bytesRead); error != StreamError::SUCCESS)
+        {
+            co_return error;
+        }
+        outString.append(chunk.data(), chunk.data() + bytesRead);
+    }
+    co_return StreamError::SUCCESS;
+}
+
 
 inline const char* errorName(StreamError error) noexcept
 {
@@ -271,6 +428,8 @@ inline const char* errorName(StreamError error) noexcept
             return "IO error";
         case StreamError::NOT_SUPPORTED:
             return "not supported";
+        case StreamError::CONNECTION_CLOSED:
+            return "connection closed";
         case StreamError::UNKNOWN_ERROR:
             return "unknown error";
     }

source/mijin/net/socket.cpp

@@ -0,0 +1,271 @@
+
+#include "./socket.hpp"
+
+#include "../detect.hpp"
+
+#if MIJIN_TARGET_OS == MIJIN_OS_LINUX
+#include <fcntl.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#endif
+
+namespace mijin
+{
+namespace
+{
+inline constexpr int LISTEN_BACKLOG = 3;
+StreamError translateErrno() noexcept
+{
+    switch (errno)
+    {
+        default:
+            return StreamError::UNKNOWN_ERROR;
+    }
+}
+
+bool appendSocketFlags(int handle, int flags) noexcept
+{
+    const int currentFlags = fcntl(handle, F_GETFL);
+    if (currentFlags < 0)
+    {
+        return false;
+    }
+    return fcntl(handle, F_SETFL, currentFlags | flags) >= 0;
+}
+
+bool removeSocketFlags(int handle, int flags) noexcept
+{
+    const int currentFlags = fcntl(handle, F_GETFL);
+    if (currentFlags < 0)
+    {
+        return false;
+    }
+    return fcntl(handle, F_SETFL, currentFlags & ~flags) >= 0;
+}
+
+int readFlags(const ReadOptions& options)
+{
+    return (options.partial ? 0 : MSG_WAITALL)
+         | (options.peek ? MSG_PEEK : 0);
+}
+}
+
+StreamError TCPStream::readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
+{
+    MIJIN_ASSERT(isOpen(), "Socket is not open.");
+    setAsync(false);
+
+    const ::ssize_t bytesRead = recv(handle_, buffer.data(), buffer.size(), readFlags(options));
+    if (bytesRead < 0)
+    {
+        return translateErrno();
+    }
+    *outBytesRead = static_cast<std::size_t>(bytesRead);
+
+    return StreamError::SUCCESS;
+}
+
+StreamError TCPStream::writeRaw(std::span<const std::uint8_t> buffer)
+{
+    MIJIN_ASSERT(isOpen(), "Socket is not open.");
+    setAsync(false);
+
+    if (send(handle_, buffer.data(), buffer.size(), 0) < 0)
+    {
+        return translateErrno();
+    }
+
+    return StreamError::SUCCESS;
+}
+
+mijin::Task<StreamError> TCPStream::c_readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead)
+{
+    MIJIN_ASSERT(isOpen(), "Socket is not open.");
+    setAsync(true);
+
+    while(true)
+    {
+        const ::ssize_t bytesRead = recv(handle_, buffer.data(), buffer.size(), readFlags(options));
+        if (bytesRead >= 0)
+        {
+            if (outBytesRead != nullptr) {
+                *outBytesRead = static_cast<std::size_t>(bytesRead);
+            }
+            co_return StreamError::SUCCESS;
+        }
+        else if (errno != EAGAIN)
+        {
+            co_return translateErrno();
+        }
+        co_await mijin::c_suspend();
+    }
+}
+
+mijin::Task<StreamError> TCPStream::c_writeRaw(std::span<const std::uint8_t> buffer)
+{
+    MIJIN_ASSERT(isOpen(), "Socket is not open.");
+    setAsync(true);
+
+    while (true)
+    {
+        if (send(handle_, buffer.data(), buffer.size(), 0) >= 0)
+        {
+            co_return StreamError::SUCCESS;
+        }
+        else if (errno != EAGAIN)
+        {
+            co_return translateErrno();
+        }
+        co_await mijin::c_suspend();
+    }
+}
+
+void TCPStream::setAsync(bool async)
+{
+    if (async == async_)
+    {
+        return;
+    }
+    async_ = async;
+
+    if (async)
+    {
+        appendSocketFlags(handle_, O_NONBLOCK);
+    }
+    else
+    {
+        removeSocketFlags(handle_, O_NONBLOCK);
+    }
+}
+
+std::size_t TCPStream::tell()
+{
+    return 0;
+}
+
+StreamError TCPStream::seek(std::intptr_t /* pos */, mijin::SeekMode /* seekMode */)
+{
+    return StreamError::NOT_SUPPORTED;
+}
+
+void TCPStream::flush()
+{
+
+}
+
+bool TCPStream::isAtEnd()
+{
+    return !isOpen();
+}
+
+StreamFeatures TCPStream::getFeatures()
+{
+    return {
+        .read = true,
+        .write = true,
+        .tell = false,
+        .seek = false,
+        .async = true,
+        .readOptions = {
+            .partial = true,
+            .peek = true
+        }
+    };
+}
+
+StreamError TCPStream::open(const char* address, std::uint16_t port) noexcept
+{
+    MIJIN_ASSERT(!isOpen(), "Socket is already open.");
+
+    handle_ = socket(AF_INET, SOCK_STREAM, 0);
+    if (handle_ < 0)
+    {
+        return translateErrno();
+    }
+    sockaddr_in connectAddress =
+    {
+        .sin_family = AF_INET,
+        .sin_port = htons(port),
+        .sin_addr = {inet_addr(address)}
+    };
+    if (connect(handle_, reinterpret_cast<sockaddr*>(&connectAddress), sizeof(sockaddr_in)) < 0)
+    {
+        ::close(handle_);
+        handle_ = -1;
+        return translateErrno();
+    }
+
+    return StreamError::SUCCESS;
+}
+
+void TCPStream::close() noexcept
+{
+    MIJIN_ASSERT(isOpen(), "Socket is not open.");
+    ::close(handle_);
+    handle_ = -1;
+}
+
+TCPStream& TCPSocket::getStream() noexcept
+{
+    return stream_;
+}
+
+StreamError TCPServerSocket::setup(const char* address, std::uint16_t port) noexcept
+{
+    MIJIN_ASSERT(!isListening(), "Socket is already listening.");
+
+    handle_ = socket(AF_INET, SOCK_STREAM, 0);
+    if (handle_ < 0)
+    {
+        return translateErrno();
+    }
+    sockaddr_in bindAddress =
+    {
+        .sin_family = AF_INET,
+        .sin_port = htons(port),
+        .sin_addr = {inet_addr(address)}
+    };
+    static const int ONE = 1;
+    if ((setsockopt(handle_, SOL_SOCKET, SO_REUSEADDR, &ONE, sizeof(int)))
+        || (bind(handle_, reinterpret_cast<sockaddr*>(&bindAddress), sizeof(sockaddr_in)) < 0)
+        || (listen(handle_, LISTEN_BACKLOG) < 0)
+        || !appendSocketFlags(handle_, O_NONBLOCK))
+    {
+        close();
+        return translateErrno();
+    }
+    return StreamError::SUCCESS;
+}
+
+void TCPServerSocket::close() noexcept
+{
+    MIJIN_ASSERT(isListening(), "Socket is not listening.");
+
+    ::close(handle_);
+    handle_ = -1;
+}
+
+Task<StreamResult<std::unique_ptr<Socket>>> TCPServerSocket::c_waitForConnection() noexcept
+{
+    while (isListening())
+    {
+        sockaddr_in client = {0};
+        socklen_t LENGTH = sizeof(sockaddr_in);
+        const int newSocket = accept(handle_, reinterpret_cast<sockaddr*>(&client), &LENGTH);
+        if (newSocket < 0)
+        {
+            if (errno != EAGAIN)
+            {
+                co_return translateErrno();
+            }
+            co_await c_suspend();
+            continue;
+        }
+        std::unique_ptr<TCPSocket> socket = std::make_unique<TCPSocket>();
+        socket->stream_.handle_ = newSocket;
+        co_return socket;
+    }
+    co_return StreamError::CONNECTION_CLOSED;
+}
+}

source/mijin/net/socket.hpp

@@ -0,0 +1,100 @@
+
+#pragma once
+
+#if !defined(MIJIN_NET_SOCKET_HPP_INCLUDED)
+#define MIJIN_NET_SOCKET_HPP_INCLUDED 1
+
+#include "../async/coroutine.hpp"
+#include "../io/stream.hpp"
+
+namespace mijin
+{
+
+//
+// public types
+//
+
+class Socket
+{
+protected:
+    Socket() noexcept = default;
+    Socket(const Socket&) noexcept = default;
+    Socket(Socket&&) noexcept = default;
+
+    Socket& operator=(const Socket&) noexcept = default;
+    Socket& operator=(Socket&&) noexcept = default;
+public:
+    virtual ~Socket() noexcept = default;
+
+    virtual Stream& getStream() noexcept = 0;
+};
+
+class ServerSocket
+{
+protected:
+    ServerSocket() noexcept = default;
+    ServerSocket(const ServerSocket&) noexcept = default;
+    ServerSocket(ServerSocket&&) noexcept = default;
+
+    ServerSocket& operator=(const ServerSocket&) noexcept = default;
+    ServerSocket& operator=(ServerSocket&&) noexcept = default;
+public:
+    virtual ~ServerSocket() noexcept = default;
+
+    virtual void close() noexcept = 0;
+    virtual Task<StreamResult<std::unique_ptr<Socket>>> c_waitForConnection() noexcept = 0;
+};
+
+class TCPStream : public Stream
+{
+private:
+    int handle_ = -1;
+    bool async_ = false;
+public:
+    StreamError readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t* outBytesRead) override;
+    StreamError writeRaw(std::span<const std::uint8_t> buffer) override;
+    mijin::Task<StreamError> c_readRaw(std::span<std::uint8_t> buffer, const ReadOptions& options, std::size_t *outBytesRead) override;
+    mijin::Task<StreamError> c_writeRaw(std::span<const std::uint8_t> buffer) override;
+    std::size_t tell() override;
+    StreamError seek(std::intptr_t pos, SeekMode seekMode = SeekMode::ABSOLUTE) override;
+    void flush() override;
+    bool isAtEnd() override;
+    StreamFeatures getFeatures() override;
+
+    StreamError open(const char* address, std::uint16_t port) noexcept;
+    void close() noexcept;
+    [[nodiscard]] bool isOpen() const noexcept { return handle_ >= 0; }
+private:
+    void setAsync(bool async);
+
+    friend class TCPServerSocket;
+};
+
+class TCPSocket : public Socket
+{
+private:
+    TCPStream stream_;
+public:
+    TCPStream& getStream() noexcept override;
+
+    StreamError open(const char* address, std::uint16_t port) noexcept { return stream_.open(address, port); }
+    void close() noexcept { stream_.close(); }
+    [[nodiscard]] bool isOpen() const noexcept { return stream_.isOpen(); }
+
+    friend class TCPServerSocket;
+};
+
+class TCPServerSocket : public ServerSocket
+{
+private:
+    int handle_ = -1;
+public:
+    StreamError setup(const char* address, std::uint16_t port) noexcept;
+    void close() noexcept override;
+    [[nodiscard]] bool isListening() const noexcept { return handle_ >= 0; }
+
+    Task<StreamResult<std::unique_ptr<Socket>>> c_waitForConnection() noexcept override;
+};
+}
+
+#endif // !defined(MIJIN_NET_SOCKET_HPP_INCLUDED)