Documentation, use of liberror, and implement libaxl_deallocate_id

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

11 files changed, 201 insertions, 17 deletions

diff --git a/LIBAXL_REQUEST_CLEAR_AREA.3 b/LIBAXL_REQUEST_CLEAR_AREA.3
new file mode 100644
index 0000000..1957ce7
--- /dev/null
+++ b/LIBAXL_REQUEST_CLEAR_AREA.3
@@ -0,0 +1,86 @@
+.TH LIBAXL_REQUEST_CLEAR_AREA 3 libaxl
+.SH NAME
+LIBAXL_REQUEST_CLEAR_AREA - Restore background
+.SH SYNOPSIS
+.nf
+#include <libaxl.h>
+
+#define LIBAXL_REQUEST_CLEAR_AREA 61
+struct libaxl_request_clear_area {
+        uint8_t         \fIopcode\fP;
+        libaxl_bool_t   \fIexposures\fP;
+        uint16_t        \fI_request_length\fP;
+        libaxl_window_t \fIwindow\fP;
+        int16_t         \fIx\fP;
+        int16_t         \fIy\fP;
+        uint16_t        \fIwidth\fP;
+        uint16_t        \fIheight\fP;
+};
+.fi
+.SH DESCRIPTION
+The display server shall redraw the window's,
+whose ID is specified in the
+.I window
+field, background in the rectangle specified
+by the
+.IR x ,
+.IR y ,
+.IR width ,
+and
+.IR height .
+.PP
+The
+.I x
+and
+.I y
+fields specify the rectangles top left corner
+as pixels offset right of and down from the
+window's top left corner. The
+.I width
+and
+.I height
+fields specify the width and height, in
+pixels, of the rectangle, however the
+specified
+.I width
+is 0, than the rectangle stretches to the
+right edge of the window, and if the specified
+.I height
+is 0, than the rectangle stretches to the
+bottom edge of the window.
+.PP
+If the
+.I exposures
+field is set to
+.IR LIBAXL_TRUE ,
+one or more
+.I LIBAXL_EVENT_EXPOSE
+events are generated for regions of the rectangle
+that are either visible or are being retained in
+a backing store.
+.PP
+The value of the
+.I opcode
+field shall be
+.I LIBAXL_REQUEST_CLEAR_AREA
+to signify that the request is of the
+request described in this document.
+.PP
+Other fields are filled in automatically by the
+.BR libaxl_send_request (3)
+function.
+.SH ERRORS
+.TP
+.BR LIBAXL_ERROR_MATCH (3)
+The window with the specified window ID
+is an input-only window.
+.TP
+.BR LIBAXL_ERROR_VALUE (3)
+TODO \" LIBAXL_ERROR_VALUE
+.TP
+.BR LIBAXL_ERROR_WINDOW (3)
+The specified window ID does not exist.
+.SH REPLIES
+None
+.SH SEE ALSO
+.BR libaxl_send_request (3)
diff --git a/Makefile b/Makefile
index 4f1114e..720bf58 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,7 @@ OBJ =\
 	libaxl_context_create.o\
 	libaxl_context_free.o\
 	libaxl_create.o\
+	libaxl_deallocate_id.o\
 	libaxl_detach.o\
 	libaxl_fileno.o\
 	libaxl_flush.o\
diff --git a/common.h b/common.h
index e57fd78..3d76d23 100644
--- a/common.h
+++ b/common.h
@@ -31,6 +31,7 @@
 # include <liberror-libc.h>
 #else
 # if defined(NO_LIBERROR)
+#  define __checked_int(X, _FUN)     X
 #  define __checked_ptr(X, _FUN)     X
 #  define __checked_ssize_t(X, _FUN) X
 # else
@@ -42,10 +43,14 @@
 			liberror_set_error_errno(strerror(errno), func, errno);\
 		return ret;\
 	}
+DEFINE_CHECKED(int, __checked_int)
 DEFINE_CHECKED(void *, __checked_ptr)
 DEFINE_CHECKED(ssize_t, __checked_ssize_t)
 # endif
+# define liberror_snprintf(...)           __checked_int(snprintf(__VA_ARGS__), "snprintf")
+# define liberror_close(FD)               __checked_int(close(FD), "close")
 # define liberror_malloc(N)               __checked_ptr(malloc(N), "malloc")
+# define liberror_calloc(N, M)            __checked_ptr(calloc(N, M), "calloc")
 # define liberror_realloc(P, N)           __checked_ptr(realloc(P, N), "realloc")
 # define liberror_send(FD, B, N, F, _NAM) __checked_ssize_t(send(FD, B, N, F), "send")
 # define liberror_recv(FD, B, N, F, _NAM) __checked_ssize_t(recv(FD, B, N, F), "recv")
@@ -55,21 +60,28 @@ DEFINE_CHECKED(ssize_t, __checked_ssize_t)
 
 #define X_TCP_PORT 6000
 
+struct id_pool {
+	uint32_t        first;
+	uint32_t        last;
+	struct id_pool *next;
+};
+
 struct libaxl_connection {
-	int                         fd;
-	uint16_t                    last_seqnum;
+	int                              fd;
+	uint16_t                         last_seqnum;
 	LIBAXL_CONNECTION_RWLOCK;
-	LIBAXL_CONTEXT             *pending_out;
-	size_t                      in_progress;
-	size_t                      in_buf_size;
-	char                       *in_buf;
-	uint32_t                    xid_base;
-	uint32_t                    xid_max;
-	uint32_t                    xid_shift;
-	volatile _Atomic uint32_t   xid_last;
-	uint8_t                     request_map[1UL << 16];
-	struct libaxl_display_info  info;
-	char                       *info_buf;
+	LIBAXL_CONTEXT                  *pending_out;
+	size_t                           in_progress;
+	size_t                           in_buf_size;
+	char                            *in_buf;
+	uint32_t                         xid_base;
+	uint32_t                         xid_max;
+	uint32_t                         xid_shift;
+	volatile _Atomic uint32_t        xid_last;
+	struct id_pool *_Atomic volatile xid_pool;
+	uint8_t                          request_map[1UL << 16];
+	struct libaxl_display_info       info;
+	char                            *info_buf;
 };
 
 struct libaxl_context {
diff --git a/libaxl.h b/libaxl.h
index d9b3d26..fd0c9c1 100644
--- a/libaxl.h
+++ b/libaxl.h
@@ -194,7 +194,7 @@ libaxl_id_t libaxl_generate_id(LIBAXL_CONTEXT *);
  * @return       0 on success, a negative libaxl error code on failure
  */
 _LIBAXL_GCC_ONLY(__attribute__((__nonnull__)))
-int libaxl_deallocate_id(LIBAXL_CONTEXT *, libaxl_id_t); /* TODO implement */
+int libaxl_deallocate_id(LIBAXL_CONTEXT *, libaxl_id_t);
 
 /**
  * Send a request to the display server
diff --git a/libaxl/display-info.h b/libaxl/display-info.h
index 66a39d5..91ceac2 100644
--- a/libaxl/display-info.h
+++ b/libaxl/display-info.h
@@ -305,6 +305,8 @@ struct libaxl_display_info {
 
 	/**
 	 * The default screen
+	 * 
+	 * `NULL` if the specified default screen does not exist
 	 */
 	const struct libaxl_screen *default_screen;
 };
diff --git a/libaxl_close.c b/libaxl_close.c
index 4d9c488..8964f95 100644
--- a/libaxl_close.c
+++ b/libaxl_close.c
@@ -4,5 +4,5 @@
 int
 libaxl_close(LIBAXL_CONNECTION *conn)
 {
-	return close(libaxl_detach(conn));
+	return liberror_close(libaxl_detach(conn));
 }
diff --git a/libaxl_create.c b/libaxl_create.c
index 5c78c27..3d6d7b6 100644
--- a/libaxl_create.c
+++ b/libaxl_create.c
@@ -5,7 +5,7 @@ LIBAXL_CONNECTION *
 libaxl_create(int fd)
 {
 	LIBAXL_CONNECTION *conn;
-	conn = calloc(1, sizeof(*conn));
+	conn = liberror_calloc(1, sizeof(*conn));
 	if (conn) {
 		conn->fd = fd;
 		atomic_init(&conn->xid_last, 0);
diff --git a/libaxl_deallocate_id.c b/libaxl_deallocate_id.c
new file mode 100644
index 0000000..0a27de0
--- /dev/null
+++ b/libaxl_deallocate_id.c
@@ -0,0 +1,52 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+int
+libaxl_deallocate_id(LIBAXL_CONTEXT *ctx, libaxl_id_t id)
+{
+	LIBAXL_CONNECTION *conn = ctx->conn;
+	struct id_pool *pool = NULL, *node;
+	uint32_t inc = (uint32_t)1 << conn->xid_shift;
+	int ret = 0;
+
+	pool = atomic_exchange(&conn->xid_pool, pool);
+	if (pool) {
+		for (node = pool;; node = node->next) {
+			if (id + inc == node->first) {
+				node->first = id;
+				goto out;
+			} else if (node->last + inc == id) {
+				node->last = id;
+				goto out;
+			}
+			if (!node->next)
+				break;
+		}
+		node->next = liberror_malloc(sizeof(*node->next));
+		if (node->next) {
+			node->next->first = id;
+			node->next->last = id;
+			atomic_init(&node->next->next, NULL);
+		} else {
+			ret = -1;
+		}
+	} else {
+		pool = liberror_malloc(sizeof(*pool));
+		if (pool) {
+			pool->first = id;
+			pool->last = id;
+			atomic_init(&pool->next, NULL);
+		} else {
+			ret = -1;
+		}
+	}
+
+out:
+	while ((pool = atomic_exchange(&conn->xid_pool, pool))) {
+		for (node = pool; node->next; node = node->next);
+		node->next = atomic_exchange(&conn->xid_pool, NULL);
+	}
+
+	return ret;
+}
+
diff --git a/libaxl_detach.c b/libaxl_detach.c
index c4a0a21..72343a9 100644
--- a/libaxl_detach.c
+++ b/libaxl_detach.c
@@ -6,11 +6,16 @@ libaxl_detach(LIBAXL_CONNECTION *conn)
 {
 	int fd = conn->fd;
 	LIBAXL_CONTEXT *ctx;
+	struct id_pool *pool, *next_pool;
 	while (conn->pending_out) {
 		ctx = conn->pending_out;
 		conn->pending_out = ctx->next_pending_out;
 		libaxl_context_free(ctx);
 	}
+	for (pool = atomic_load(&conn->xid_pool); pool; pool = next_pool) {
+		next_pool = pool->next;
+		free(pool);
+	}
 	free(conn->in_buf);
 	free(conn->info_buf);
 	free(conn);
diff --git a/libaxl_generate_id.c b/libaxl_generate_id.c
index 232ef4d..91b5aa6 100644
--- a/libaxl_generate_id.c
+++ b/libaxl_generate_id.c
@@ -5,8 +5,34 @@ libaxl_id_t
 libaxl_generate_id(LIBAXL_CONTEXT *ctx)
 {
 	LIBAXL_CONNECTION *conn = ctx->conn;
+	struct id_pool *pool = NULL, *next, *last;
 	uint32_t id;
 
+	pool = atomic_exchange(&conn->xid_pool, pool);
+	if (pool) {
+		id = pool->first;
+		pool->first += (uint32_t)1 << conn->xid_shift;
+		if (id == pool->last) {
+			next = pool->next;
+			if (next) {
+				free(pool);
+				pool = next;
+			}
+			next = NULL;
+			if (atomic_compare_exchange_strong(&conn->xid_pool, &next, pool))
+				return id;
+			if (!pool->next) {
+				free(pool);
+				return id;
+			}
+		}
+		while ((pool = atomic_exchange(&conn->xid_pool, pool))) {
+			for (last = pool; last->next; last = last->next);
+			last->next = atomic_exchange(&conn->xid_pool, NULL);
+		}
+		return id;
+	}
+
 	id = atomic_fetch_add(&conn->xid_last, 1);
 	if (id <= conn->xid_max)
 		return (id << conn->xid_shift) | conn->xid_base;
diff --git a/libaxl_get_decnet_object.c b/libaxl_get_decnet_object.c
index a744fd2..a29d140 100644
--- a/libaxl_get_decnet_object.c
+++ b/libaxl_get_decnet_object.c
@@ -4,5 +4,5 @@
 int
 libaxl_get_decnet_object(char *buf, size_t size, int display)
 {
-	return snprintf(buf, size, "X$X%i", display);
+	return liberror_snprintf(buf, size, "X$X%i", display);
 }