ipc message class, does not do reading yet

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/src/libmdsserver/mds-message.h b/src/libmdsserver/mds-message.h
new file mode 100644
index 0000000..f04a8c6
--- /dev/null
+++ b/src/libmdsserver/mds-message.h
@@ -0,0 +1,133 @@
+/**
+ * mds — A micro-display server
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program 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 program 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 program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef MDS_LIBMDSSERVER_MDS_MESSAGE_H
+#define MDS_LIBMDSSERVER_MDS_MESSAGE_H
+
+
+#include <stddef.h>
+
+
+/**
+ * Message passed between a server and a client or between two of either
+ */
+typedef struct mds_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 not headers.
+   */
+  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;
+  
+  /**
+   * Internal buffer for the reading function
+   */
+  char* buffer;
+  
+  /**
+   * The size allocated to `buffer`
+   */
+  size_t buffer_size;
+  
+  /**
+   * The number of bytes used in `buffer`
+   */
+  size_t buffer_ptr;
+  
+} mds_message_t;
+
+
+/**
+ * Initialsie a message slot so that it can
+ * be used by `mds_message_read`.
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @return        Non-zero on error, errno will be set accordingly.
+ *                Destroy the message on error.
+ */
+int mds_message_initialise(mds_message_t* this);
+
+/**
+ * Release all resources in a message, should
+ * be done even if initialisation fails
+ * 
+ * @param  this  The message
+ */
+void mds_message_destroy(mds_message_t* this);
+
+/**
+ * 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, errno will be set accordingly.
+ *                Destroy the message on error.
+ */
+int mds_message_read(mds_message_t* this, int fd);
+
+/**
+ * Get the required allocation size for `data` of the
+ * function `mds_message_marshal`
+ * 
+ * @param   this            The message
+ * @param   include_buffer  Whether buffer should be marshalled (state serialisation, not communication)
+ * @return                  The size of the message when marshalled
+ */
+size_t mds_message_marshal_size(mds_message_t* this, int include_buffer) __attribute__((pure));
+
+/**
+ * Marshal a message, this can be used both when serialising
+ * the servers state or to get the byte stream to send to
+ * the recipient of the message
+ * 
+ * @param  this            The message
+ * @param  data            Output buffer for the marshalled data
+ * @param  include_buffer  Whether buffer should be marshalled (state serialisation, not communication)
+ */
+void mds_message_marshal(mds_message_t* this, char* data, int include_buffer);
+
+/**
+ * Unmarshal a message, it is assumed that the buffer is marshalled
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   data  In buffer with the marshalled data
+ * @return        Non-zero on error, errno will be set accordingly.
+ *                Destroy the message on error.
+ */
+int mds_message_unmarshal(mds_message_t* this, char* data);
+
+
+#endif
+