whitespace + Add message.[ch]

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 132 insertions, 0 deletions

diff --git a/src/message.h b/src/message.h
new file mode 100644
index 0000000..163d806
--- /dev/null
+++ b/src/message.h
@@ -0,0 +1,132 @@
+/**
+ * gammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stddef.h>
+
+
+
+/**
+ * Message passed between a server and a client
+ */
+struct message
+{
+  /**
+   * The headers in the message, each element in this list
+   * as an unparsed header, it consists of both the header
+   * name and its associated value, joined by ": ". A header
+   * cannot be `NULL` (unless its memory allocation failed,)
+   * but `headers` itself is `NULL` if there are no headers.
+   * The "Length" header should be included in this list.
+   */
+  char** headers;
+  
+  /**
+   * The number of headers in the message
+   */
+  size_t header_count;
+  
+  /**
+   * The payload of the message, `NULL` if none (of zero-length)
+   */
+  char* payload;
+  
+  /**
+   * The size of the payload
+   */
+  size_t payload_size;
+  
+  /**
+   * How much of the payload that has been stored (internal data)
+   */
+  size_t payload_ptr;
+  
+  /**
+   * Internal buffer for the reading function (internal data)
+   */
+  char* buffer;
+  
+  /**
+   * The size allocated to `buffer` (internal data)
+   */
+  size_t buffer_size;
+  
+  /**
+   * The number of bytes used in `buffer` (internal data)
+   */
+  size_t buffer_ptr;
+  
+  /**
+   * 0 while reading headers, 1 while reading payload, and 2 when done (internal data)
+   */
+  int stage;
+  
+};
+
+
+
+/**
+ * Initialise a message slot so that it can
+ * be used by to read messages
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @return        Non-zero on error, `errno` will be set accordingly
+ */
+int message_initialise(struct message* this);
+
+/**
+ * Release all resources in a message, should
+ * be done even if initialisation fails
+ * 
+ * @param  this  The message
+ */
+void message_destroy(struct message* this);
+
+/**
+ * Marshal a message for state serialisation
+ * 
+ * @param  this  The message
+ * @param  buf   Output buffer for the marshalled data,
+ *               `NULL` just measure how large the buffers
+ *               needs to be
+ * @return       The number of marshalled byte
+ */
+size_t message_marshal(const struct message* this, void* buf);
+
+/**
+ * Unmarshal a message for state deserialisation
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   buf   In buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+size_t message_unmarshal(struct message* this, const void* buf);
+
+/**
+ * Read the next message from a file descriptor
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   fd    The file descriptor
+ * @return        Non-zero on error or interruption, `errno` will be
+ *                set accordingly. Destroy the message on error,
+ *                be aware that the reading could have been
+ *                interrupted by a signal rather than canonical error.
+ *                If -2 is returned `errno` will not have been set,
+ *                -2 indicates that the message is malformated,
+ *                which is a state that cannot be recovered from.
+ */
+int message_read(struct message* this, int fd);
+