LibCore: Move GIODevice hierarchy from LibGUI to LibCore.

LibCore/CIODevice.cpp

@@ -0,0 +1,175 @@
+#include <LibCore/CIODevice.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <stdio.h>
+
+CIODevice::CIODevice(CObject* parent)
+    : CObject(parent)
+{
+}
+
+CIODevice::~CIODevice()
+{
+}
+
+const char* CIODevice::error_string() const
+{
+    return strerror(m_error);
+}
+
+ByteBuffer CIODevice::read(int max_size)
+{
+    if (m_fd < 0)
+        return { };
+    if (!max_size)
+        return { };
+    auto buffer = ByteBuffer::create_uninitialized(max_size);
+    auto* buffer_ptr = (char*)buffer.pointer();
+    int remaining_buffer_space = buffer.size();
+    if (!m_buffered_data.is_empty()) {
+        int taken_from_buffered = min(remaining_buffer_space, m_buffered_data.size());
+        memcpy(buffer_ptr, m_buffered_data.data(), taken_from_buffered);
+        Vector<byte> new_buffered_data;
+        new_buffered_data.append(m_buffered_data.data() + taken_from_buffered, m_buffered_data.size() - taken_from_buffered);
+        m_buffered_data = move(new_buffered_data);
+        remaining_buffer_space -= taken_from_buffered;
+        buffer_ptr += taken_from_buffered;
+    }
+    if (!remaining_buffer_space)
+        return buffer;
+    int nread = ::read(m_fd, buffer_ptr, remaining_buffer_space);
+    if (nread < 0) {
+        set_error(errno);
+        return { };
+    }
+    if (nread == 0) {
+        set_eof(true);
+        return { };
+    }
+    buffer.trim(nread);
+    return buffer;
+}
+
+bool CIODevice::can_read_from_fd() const
+{
+    // FIXME: Can we somehow remove this once CSocket is implemented using non-blocking sockets?
+    fd_set rfds;
+    FD_ZERO(&rfds);
+    FD_SET(m_fd, &rfds);
+    struct timeval timeout { 0, 0 };
+    int rc = select(m_fd + 1, &rfds, nullptr, nullptr, &timeout);
+    if (rc < 0) {
+        // NOTE: We don't set m_error here.
+        perror("CIODevice::can_read: select");
+        return false;
+    }
+    return FD_ISSET(m_fd, &rfds);
+}
+
+bool CIODevice::can_read_line()
+{
+    if (m_eof && !m_buffered_data.is_empty())
+        return true;
+    if (m_buffered_data.contains_slow('\n'))
+        return true;
+    if (!can_read_from_fd())
+        return false;
+    populate_read_buffer();
+    return m_buffered_data.contains_slow('\n');
+}
+
+bool CIODevice::can_read() const
+{
+    return !m_buffered_data.is_empty() || can_read_from_fd();
+}
+
+ByteBuffer CIODevice::read_all()
+{
+    ByteBuffer buffer;
+    if (!m_buffered_data.is_empty()) {
+        buffer = ByteBuffer::copy(m_buffered_data.data(), m_buffered_data.size());
+        m_buffered_data.clear();
+    }
+
+    while (can_read_from_fd()) {
+        char read_buffer[4096];
+        int nread = ::read(m_fd, read_buffer, sizeof(read_buffer));
+        if (nread < 0) {
+            set_error(nread);
+            return buffer;
+        }
+        if (nread == 0) {
+            set_eof(true);
+            break;
+        }
+        buffer.append(read_buffer, nread);
+    }
+    return buffer;
+}
+
+ByteBuffer CIODevice::read_line(int max_size)
+{
+    if (m_fd < 0)
+        return { };
+    if (!max_size)
+        return { };
+    if (!can_read_line())
+        return { };
+    if (m_eof) {
+        if (m_buffered_data.size() > max_size) {
+            printf("CIODevice::read_line: At EOF but there's more than max_size(%d) buffered\n", max_size);
+            return { };
+        }
+        auto buffer = ByteBuffer::copy(m_buffered_data.data(), m_buffered_data.size());
+        m_buffered_data.clear();
+        return buffer;
+    }
+    auto line = ByteBuffer::create_uninitialized(max_size + 1);
+    int line_index = 0;
+    while (line_index < max_size) {
+        byte ch = m_buffered_data[line_index];
+        line[line_index++] = ch;
+        if (ch == '\n') {
+            Vector<byte> new_buffered_data;
+            new_buffered_data.append(m_buffered_data.data() + line_index, m_buffered_data.size() - line_index);
+            m_buffered_data = move(new_buffered_data);
+            line[line_index] = '\0';
+            line.trim(line_index + 1);
+            return line;
+        }
+    }
+    return { };
+}
+
+bool CIODevice::populate_read_buffer()
+{
+    if (m_fd < 0)
+        return false;
+    auto buffer = ByteBuffer::create_uninitialized(PAGE_SIZE);
+    int nread = ::read(m_fd, buffer.pointer(), buffer.size());
+    if (nread < 0) {
+        set_error(errno);
+        return false;
+    }
+    if (nread == 0) {
+        set_eof(true);
+        return false;
+    }
+    buffer.trim(nread);
+    m_buffered_data.append(buffer.pointer(), buffer.size());
+    return true;
+}
+
+bool CIODevice::close()
+{
+    if (fd() < 0 || mode() == NotOpen)
+        return false;
+    int rc = ::close(fd());
+    if (rc < 0) {
+        set_error(rc);
+        return false;
+    }
+    set_fd(-1);
+    set_mode(CIODevice::NotOpen);
+    return true;
+}