misc

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

1 files changed, 82 insertions, 0 deletions

diff --git a/libgamma_x_randr_site_initialise.c b/libgamma_x_randr_site_initialise.c
new file mode 100644
index 0000000..61c011b
--- /dev/null
+++ b/libgamma_x_randr_site_initialise.c
@@ -0,0 +1,82 @@
+/* See LICENSE file for copyright and license details. */
+#define IN_LIBGAMMA_X_RANDR
+#include "common.h"
+
+
+/**
+ * Initialise an allocated site state
+ * 
+ * @param   this    The site state to initialise
+ * @param   site    The site identifier, unless it is `NULL` it must a
+ *                  `free`:able. Once the state is destroyed the library
+ *                  will attempt to free it. There you should not free
+ *                  it yourself, and it must not be a string constant
+ *                  or allocate on the stack. Note however that it will
+ *                  not be free:d if this function fails.
+ * @return          Zero on success, otherwise (negative) the value of an
+ *                  error identifier provided by this library
+ */
+int
+libgamma_x_randr_site_initialise(libgamma_site_state_t *restrict this, char *restrict site)
+{
+	xcb_generic_error_t *error = NULL;
+	xcb_connection_t *restrict connection;
+	xcb_randr_query_version_cookie_t cookie;
+	xcb_randr_query_version_reply_t *restrict reply;
+	const xcb_setup_t *restrict setup;
+	xcb_screen_iterator_t iter;
+
+	/* Connect to the display server */
+	this->data = connection = xcb_connect(site, NULL);
+	if (!connection || xcb_connection_has_error(connection))
+		return LIBGAMMA_OPEN_SITE_FAILED;
+
+	/* Query the version of the X RandR extension protocol */
+	cookie = xcb_randr_query_version(connection, RANDR_VERSION_MAJOR, RANDR_VERSION_MINOR);
+	reply = xcb_randr_query_version_reply(connection, cookie, &error);
+
+	/* Check for version query failure */
+	if (error || !reply) {
+		/* Release resources */
+		free(reply);
+		/* If `xcb_connect` failed, both `error` and `reply` will be `NULL`.
+		 * TODO: Can both be `NULL` for any other reason? */
+		if (!error && !reply)
+			return LIBGAMMA_OPEN_SITE_FAILED;
+		xcb_disconnect(connection);
+		/* Translate and report error. */
+		if (error != NULL)
+			return libgamma_x_randr_internal_translate_error(error->error_code, LIBGAMMA_PROTOCOL_VERSION_QUERY_FAILED, 0);
+		return LIBGAMMA_PROTOCOL_VERSION_QUERY_FAILED;
+	}
+
+	/* Check protocol compatibility,
+	   we require 1.3 but 2.x may not be backwards compatible */
+	if (reply->major_version != RANDR_VERSION_MAJOR || reply->minor_version < RANDR_VERSION_MINOR) {
+#ifdef DEBUG
+		/* Print used protocol */
+		fprintf(stderr, "libgamma: RandR protocol version: %u.%u", reply->major_version, reply->minor_version);
+#endif
+		/* Release resources */
+		free(reply);
+		xcb_disconnect(connection);
+		/* Report error */
+		return LIBGAMMA_PROTOCOL_VERSION_NOT_SUPPORTED;
+	}
+
+	/* We do not longer need to know the version of the protocol */
+	free(reply);
+
+	/* Get available screens */
+	setup = xcb_get_setup(connection);
+	if (!setup) {
+		xcb_disconnect(connection);
+		return LIBGAMMA_LIST_PARTITIONS_FAILED;
+	}
+	iter = xcb_setup_roots_iterator(setup);
+	/* Get the number of available screens */
+	this->partitions_available = (size_t)iter.rem;
+
+	/* Sanity check the number of available screens. */
+	return iter.rem >= 0 ? 0 : LIBGAMMA_NEGATIVE_PARTITION_COUNT;
+}