LibGUI: Add GTCPSocket and base class GSocket (inherits from GIODevice.)

And use these to do the line-by-line reading automagically instead of having
that logic in IRCClient. This will definitely come in handy.

9 files changed, 230 insertions, 23 deletions

diff --git a/LibGUI/GFile.cpp b/LibGUI/GFile.cpp
index 45b083191c..e0ff42e0bb 100644
--- a/LibGUI/GFile.cpp
+++ b/LibGUI/GFile.cpp
@@ -40,17 +40,3 @@ bool GFile::open(GIODevice::OpenMode mode)
     set_mode(mode);
     return true;
 }
-
-bool GFile::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(GIODevice::NotOpen);
-    return true;
-}
diff --git a/LibGUI/GFile.h b/LibGUI/GFile.h
index de7325fb93..89aadf0aad 100644
--- a/LibGUI/GFile.h
+++ b/LibGUI/GFile.h
@@ -13,7 +13,6 @@ public:
     void set_filename(const String& filename) { m_filename = filename; }
 
     virtual bool open(GIODevice::OpenMode) override;
-    virtual bool close() override;
 
     virtual const char* class_name() const override { return "GFile"; }
 
diff --git a/LibGUI/GIODevice.cpp b/LibGUI/GIODevice.cpp
index d62d36622f..0b0f8de1d1 100644
--- a/LibGUI/GIODevice.cpp
+++ b/LibGUI/GIODevice.cpp
@@ -1,5 +1,7 @@
 #include <LibGUI/GIODevice.h>
 #include <unistd.h>
+#include <sys/select.h>
+#include <stdio.h>
 
 GIODevice::GIODevice(GObject* parent)
     : GObject(parent)
@@ -44,26 +46,63 @@ ByteBuffer GIODevice::read(int max_size)
     return buffer;
 }
 
+bool GIODevice::can_read() const
+{
+    // FIXME: Can we somehow remove this once GSocket 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("GIODevice::can_read: select");
+        return false;
+    }
+    return FD_ISSET(m_fd, &rfds);
+}
+
+bool GIODevice::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())
+        return false;
+    populate_read_buffer();
+    return m_buffered_data.contains_slow('\n');
+}
+
 ByteBuffer GIODevice::read_line(int max_size)
 {
     if (m_fd < 0)
         return { };
     if (!max_size)
         return { };
-    auto line = ByteBuffer::create_uninitialized(max_size);
-    int line_index = 0;
-    while (line_index < line.size()) {
-        if (line_index >= m_buffered_data.size()) {
-            if (!populate_read_buffer())
-                return { };
+    if (!can_read_line())
+        return { };
+    if (m_eof) {
+        if (m_buffered_data.size() > max_size) {
+            dbgprintf("GIODevice::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.trim(line_index);
+            line[line_index] = '\0';
+            line.trim(line_index + 1);
+            dbgprintf("GIODevice::read_line: '%s'\n", line.pointer());
             return line;
         }
     }
@@ -84,6 +123,21 @@ bool GIODevice::populate_read_buffer()
         set_eof(true);
         return false;
     }
+    buffer.trim(nread);
     m_buffered_data.append(buffer.pointer(), buffer.size());
     return true;
 }
+
+bool GIODevice::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(GIODevice::NotOpen);
+    return true;
+}
diff --git a/LibGUI/GIODevice.h b/LibGUI/GIODevice.h
index 744e1997d0..d7d7cd094c 100644
--- a/LibGUI/GIODevice.h
+++ b/LibGUI/GIODevice.h
@@ -29,8 +29,13 @@ public:
     ByteBuffer read(int max_size);
     ByteBuffer read_line(int max_size);
 
+    // FIXME: I would like this to be const but currently it needs to call populate_read_buffer().
+    bool can_read_line();
+
+    bool can_read() const;
+
     virtual bool open(GIODevice::OpenMode) = 0;
-    virtual bool close() = 0;
+    virtual bool close();
 
     virtual const char* class_name() const override { return "GIODevice"; }
 
diff --git a/LibGUI/GSocket.cpp b/LibGUI/GSocket.cpp
new file mode 100644
index 0000000000..78343f2225
--- /dev/null
+++ b/LibGUI/GSocket.cpp
@@ -0,0 +1,64 @@
+#include <LibGUI/GSocket.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+
+GSocket::GSocket(Type type, GObject* parent)
+    : GIODevice(parent)
+    , m_type(type)
+{
+}
+
+GSocket::~GSocket()
+{
+}
+
+bool GSocket::connect(const GSocketAddress& address, int port)
+{
+    ASSERT(!is_connected());
+    ASSERT(address.type() == GSocketAddress::Type::IPv4);
+    ASSERT(port > 0 && port <= 65535);
+
+    struct sockaddr_in addr;
+    memset(&addr, 0, sizeof(addr));
+    auto ipv4_address = address.ipv4_address();
+    memcpy(&addr.sin_addr.s_addr, &ipv4_address, sizeof(IPv4Address));
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+
+    printf("Connecting to %s...", address.to_string().characters());
+    fflush(stdout);
+    int rc = ::connect(fd(), (struct sockaddr*)&addr, sizeof(addr));
+    if (rc < 0) {
+        perror("connect");
+        exit(1);
+    }
+    printf("ok!\n");
+
+    m_destination_address = address;
+    m_destination_port = port;
+    m_connected = true;
+    return true;
+}
+
+ByteBuffer GSocket::receive(int max_size)
+{
+    auto buffer = read(max_size);
+    if (eof()) {
+        dbgprintf("GSocket{%p}: Connection appears to have closed in receive().\n", this);
+        m_connected = false;
+    }
+    return buffer;
+}
+
+bool GSocket::send(const ByteBuffer& data)
+{
+    int nsent = ::send(fd(), data.pointer(), data.size(), 0);
+    if (nsent < 0) {
+        set_error(nsent);
+        return false;
+    }
+    ASSERT(nsent == data.size());
+    return true;
+}
diff --git a/LibGUI/GSocket.h b/LibGUI/GSocket.h
new file mode 100644
index 0000000000..a4871f6480
--- /dev/null
+++ b/LibGUI/GSocket.h
@@ -0,0 +1,68 @@
+#pragma once
+
+#include <LibGUI/GIODevice.h>
+#include <AK/AKString.h>
+#include <Kernel/IPv4.h>
+
+class GSocketAddress {
+public:
+    enum class Type { Invalid, IPv4, Local };
+
+    GSocketAddress() { }
+    GSocketAddress(const IPv4Address& address)
+        : m_type(Type::IPv4)
+        , m_ipv4_address(address)
+    {
+    }
+
+    Type type() const { return m_type; }
+    bool is_valid() const { return m_type != Type::Invalid; }
+    IPv4Address ipv4_address() const { return m_ipv4_address; }
+
+    String to_string() const
+    {
+        switch (m_type) {
+        case Type::IPv4: return m_ipv4_address.to_string();
+        default: return "[GSocketAddress]";
+        }
+    }
+
+private:
+    Type m_type { Type::Invalid };
+    IPv4Address m_ipv4_address;
+};
+
+class GSocket : public GIODevice {
+public:
+    enum class Type { Invalid, TCP, UDP };
+    virtual ~GSocket() override;
+
+    bool connect(const GSocketAddress&, int port);
+
+    ByteBuffer receive(int max_size);
+    bool send(const ByteBuffer&);
+
+    bool is_connected() const { return m_connected; }
+
+    GSocketAddress source_address() const { return m_source_address; }
+    int source_port() const { return m_source_port; }
+
+    GSocketAddress destination_address() const { return m_source_address; }
+    int destination_port() const { return m_destination_port; }
+
+    virtual const char* class_name() const override { return "GSocket"; }
+
+protected:
+    GSocket(Type, GObject* parent);
+
+    GSocketAddress m_source_address;
+    GSocketAddress m_destination_address;
+    int m_source_port { -1 };
+    int m_destination_port { -1 };
+    bool m_connected { false };
+
+private:
+    virtual bool open(GIODevice::OpenMode) override { ASSERT_NOT_REACHED(); }
+    Type m_type { Type::Invalid };
+
+};
diff --git a/LibGUI/GTCPSocket.cpp b/LibGUI/GTCPSocket.cpp
new file mode 100644
index 0000000000..1194e8adf0
--- /dev/null
+++ b/LibGUI/GTCPSocket.cpp
@@ -0,0 +1,19 @@
+#include <LibGUI/GTCPSocket.h>
+#include <sys/socket.h>
+
+GTCPSocket::GTCPSocket(GObject* parent)
+    : GSocket(GSocket::Type::TCP, parent)
+{
+    int fd = socket(AF_INET, SOCK_STREAM, 0);
+    if (fd < 0) {
+        set_error(fd);
+    } else {
+        set_fd(fd);
+        set_mode(GIODevice::ReadWrite);
+        set_error(0);
+    }
+}
+
+GTCPSocket::~GTCPSocket()
+{
+}
diff --git a/LibGUI/GTCPSocket.h b/LibGUI/GTCPSocket.h
new file mode 100644
index 0000000000..691da1731e
--- /dev/null
+++ b/LibGUI/GTCPSocket.h
@@ -0,0 +1,10 @@
+#include <LibGUI/GSocket.h>
+
+class GTCPSocket final : public GSocket {
+public:
+    explicit GTCPSocket(GObject* parent);
+    virtual ~GTCPSocket() override;
+
+private:
+};
+
diff --git a/LibGUI/Makefile b/LibGUI/Makefile
index c39478d130..098c3cf779 100644
--- a/LibGUI/Makefile
+++ b/LibGUI/Makefile
@@ -40,6 +40,8 @@ LIBGUI_OBJS = \
     GStackWidget.o \
     GEvent.o \
     GScrollableWidget.o \
+    GSocket.o \
+    GTCPSocket.o \
     GWindow.o
 
 OBJS = $(SHAREDGRAPHICS_OBJS) $(LIBGUI_OBJS)