Initial version

This is an initial prototype on how this library might look like. All the parts
which should be auto-generated from XCB's XML protocol description are missing.
The C parts should work fine, but are completely untested.

Signed-off-by: Uli Schlachter <psychon@znc.in>

.gitignore

@@ -0,0 +1,2 @@
+src/libxcb_errors.so
+src/static_tables.inc

Makefile

@@ -0,0 +1,15 @@
+FLAGS=-std=gnu89 -Wall -Wextra -lxcb -fpic -shared -Wl,-no-undefined # -Wl,-export-symbols-regex,'^xcb_errors_'
+
+src/libxcb_errors.so: $(wildcard src/*.c) $(wildcard *.h) Makefile src/static_tables.inc syms
+	gcc $(FLAGS) -Wl,--retain-symbols-file=syms -o $@ $(wildcard src/*.c)
+
+syms:
+	echo xcb_errors_context_new > $@
+	echo xcb_errors_context_free > $@
+	echo xcb_errors_get_name_for_major_code > $@
+	echo xcb_errors_get_name_for_minor_code > $@
+	echo xcb_errors_get_name_for_event > $@
+	echo xcb_errors_get_name_for_error > $@
+
+src/static_tables.inc:
+	for x in $$(seq 0 255) ; do echo "ENTRY($$x)" ; done > $@

src/errors.h

@@ -0,0 +1,47 @@
+#ifndef __ERRORS_H__
+#define __ERRORS_H__
+
+/* Copyright © 2015 Uli Schlachter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors or their
+ * institutions shall not be used in advertising or otherwise to promote the
+ * sale, use or other dealings in this Software without prior written
+ * authorization from the authors.
+ */
+
+struct static_extension_info_t {
+	uint16_t num_minor;
+	uint8_t num_events;
+	uint8_t num_errors;
+	const char *strings_minor;
+	const char *strings_events;
+	const char *strings_errors;
+};
+
+extern const char *unknown_major_code[256];
+extern const char *unknown_error_code[256];
+extern const char *unknown_event_code[256];
+
+const char *xproto_get_name_for_major_code(uint8_t major_code);
+const char *xproto_get_name_for_event(uint8_t event_code);
+const char *xproto_get_name_for_error(uint8_t error_code);
+struct static_extension_info_t find_static_info_for_extension(const char *name);
+
+#endif /* __ERRORS_H__ */

src/static_tables.c

@@ -0,0 +1,73 @@
+/* Copyright © 2015 Uli Schlachter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors or their
+ * institutions shall not be used in advertising or otherwise to promote the
+ * sale, use or other dealings in this Software without prior written
+ * authorization from the authors.
+ */
+
+#include "xcb_errors.h"
+#include "errors.h"
+
+const char *unknown_major_code[256] = {
+#define ENTRY(i) "Unknown major code " #i,
+#include "static_tables.inc"
+#undef ENTRY
+};
+
+const char *unknown_error_code[256] = {
+#define ENTRY(i) "Unknown error " #i,
+#include "static_tables.inc"
+#undef ENTRY
+};
+
+const char *unknown_event_code[256] = {
+#define ENTRY(i) "Unknown event " #i,
+#include "static_tables.inc"
+#undef ENTRY
+};
+
+#warning TODO: Implement these
+const char *xproto_get_name_for_major_code(uint8_t major_code) {
+	(void) major_code;
+	return NULL;
+}
+
+const char *xproto_get_name_for_event(uint8_t event_code) {
+	(void) event_code;
+	return NULL;
+}
+
+const char *xproto_get_name_for_error(uint8_t error_code) {
+	(void) error_code;
+	return NULL;
+}
+struct static_extension_info_t find_static_info_for_extension(const char *name) {
+	struct static_extension_info_t info = {
+		.num_minor = 0,
+		.num_events = 0,
+		.num_errors = 0,
+		.strings_minor = NULL,
+		.strings_events = NULL,
+		.strings_errors = NULL
+	};
+	(void) name;
+	return info;
+}

src/xcb_errors.c

@@ -0,0 +1,206 @@
+/* Copyright © 2015 Uli Schlachter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors or their
+ * institutions shall not be used in advertising or otherwise to promote the
+ * sale, use or other dealings in this Software without prior written
+ * authorization from the authors.
+ */
+
+#include "xcb_errors.h"
+#include "errors.h"
+#include <stdlib.h>
+#include <string.h>
+
+struct extension_info_t {
+	struct extension_info_t *next;
+	struct static_extension_info_t static_info;
+	uint8_t major_opcode;
+	uint8_t first_event;
+	uint8_t first_error;
+	char *name;
+};
+
+struct xcb_errors_context_t {
+	xcb_connection_t *conn;
+	struct extension_info_t *extensions;
+};
+
+static const char *get_strings_entry(const char *strings, unsigned int index) {
+	while (index > 0)
+		strings += strlen(strings) + 1;
+	return strings;
+}
+
+static int register_extension(xcb_errors_context_t *ctx, const char *ext)
+{
+	struct extension_info_t *info;
+	struct static_extension_info_t static_info;
+	xcb_query_extension_reply_t *reply;
+	char *ext_dup;
+
+	ext_dup = strdup(ext);
+	info = calloc(1, sizeof(*info));
+	reply = xcb_query_extension_reply(ctx->conn,
+			xcb_query_extension(ctx->conn, strlen(ext), ext), NULL);
+	static_info = find_static_info_for_extension(ext);
+
+	if (!info || !reply || !ext_dup || !reply->present || (static_info.num_minor == 0)) {
+		free(info);
+		free(reply);
+		free(ext_dup);
+		/* This is used to indicate an unsupported extension */
+		if (static_info.num_minor == 0)
+			return 0;
+		return -1;
+	}
+
+	info->name = ext_dup;
+	info->static_info = static_info;
+	info->major_opcode = reply->major_opcode;
+	info->first_event = reply->first_event;
+	info->first_error = reply->first_error;
+
+	info->next = ctx->extensions;
+	ctx->extensions = info;
+	free(reply);
+
+	return 0;
+}
+
+int xcb_errors_context_new(xcb_connection_t *conn, xcb_errors_context_t **c)
+{
+	xcb_errors_context_t *ctx = NULL;
+	xcb_list_extensions_reply_t *reply = NULL;
+	xcb_str_iterator_t iter;
+
+	if ((*c = calloc(1, sizeof(*c))) == NULL)
+		goto error_out;
+
+	ctx = *c;
+	ctx->conn = conn;
+	ctx->extensions = NULL;
+
+	reply = xcb_list_extensions_reply(conn,
+			xcb_list_extensions(conn), NULL);
+	if (!reply)
+		goto error_out;
+
+	iter = xcb_list_extensions_names_iterator(reply);
+	while (iter.rem > 0) {
+		int status = register_extension(ctx, xcb_str_name(iter.data));
+		if (status < 0)
+			goto error_out;
+		xcb_str_next(&iter);
+	}
+
+	return 0;
+
+error_out:
+	free(reply);
+	xcb_errors_context_free(ctx);
+	*c = NULL;
+	return -1;
+}
+
+void xcb_errors_context_free(xcb_errors_context_t *ctx)
+{
+	struct extension_info_t *info;
+
+	if (ctx == NULL)
+		return;
+
+	info = ctx->extensions;
+	while (info) {
+		struct extension_info_t *prev = info;
+		info = info->next;
+		free(prev->name);
+		free(prev);
+	}
+
+	free(ctx);
+}
+
+const char *xcb_errors_get_name_for_major_code(xcb_errors_context_t *ctx,
+		uint8_t major_code)
+{
+	struct extension_info_t *info = ctx->extensions;
+	const char *result = xproto_get_name_for_major_code(major_code);
+	if (result)
+		return result;
+
+	while (info && info->major_opcode != major_code)
+		info = info->next;
+
+	if (info == NULL)
+		return unknown_major_code[major_code];
+
+	return info->name;
+}
+
+const char *xcb_errors_get_name_for_minor_code(xcb_errors_context_t *ctx,
+		uint8_t major_code,
+		uint16_t minor_code)
+{
+	struct extension_info_t *info = ctx->extensions;
+
+	while (info && info->major_opcode != major_code)
+		info = info->next;
+
+	if (info == NULL || minor_code > info->static_info.num_minor)
+		return NULL;
+
+	return get_strings_entry(info->static_info.strings_minor, minor_code);
+}
+
+const char *xcb_errors_get_name_for_event(xcb_errors_context_t *ctx,
+		uint8_t event_code)
+{
+	struct extension_info_t *info = ctx->extensions;
+	const char *result = xproto_get_name_for_event(event_code);
+	if (result)
+		return result;
+
+	while (info && (info->first_event > event_code
+				|| info->first_event + info->static_info.num_events <= event_code))
+		info = info->next;
+
+	if (info == NULL)
+		return unknown_event_code[event_code];
+
+	return get_strings_entry(info->static_info.strings_events, event_code - info->first_event);
+}
+
+const char *xcb_errors_get_name_for_error(xcb_errors_context_t *ctx,
+		uint8_t error_code)
+{
+	struct extension_info_t *info = ctx->extensions;
+	const char *result = xproto_get_name_for_error(error_code);
+	if (result)
+		return result;
+
+	while (info && (info->first_error > error_code
+				|| info->first_error + info->static_info.num_errors <= error_code))
+		info = info->next;
+
+	if (info == NULL)
+		return unknown_error_code[error_code];
+
+	return get_strings_entry(info->static_info.strings_errors, error_code - info->first_error);
+}

src/xcb_errors.h

@@ -0,0 +1,116 @@
+#ifndef __XCB_ERRORS_H__
+#define __XCB_ERRORS_H__
+
+/* Copyright © 2015 Uli Schlachter
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors or their
+ * institutions shall not be used in advertising or otherwise to promote the
+ * sale, use or other dealings in this Software without prior written
+ * authorization from the authors.
+ */
+
+#include <xcb/xcb.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * A context for using this library.
+ *
+ * Create a context with @ref xcb_errors_context_new () and destroy it with @ref
+ * xcb_errors_context_free (). Except for @ref xcb_errors_context_free (), all
+ * functions in this library are thread-safe and can be called from multiple
+ * threads at the same time, even on the same context.
+ */
+typedef struct xcb_errors_context_t xcb_errors_context_t;
+
+/**
+ * Create a new @ref xcb_errors_context_t.
+ *
+ * @param conn A XCB connection which will be used until you destroy the context
+ * with @ref xcb_errors_context_free ().
+ * @param ctx A pointer to an xcb_cursor_context_t* which will be modified to
+ * refer to the newly created context.
+ * @return 0 on success, some other value otherwise.
+ */
+int xcb_errors_context_new(xcb_connection_t *conn, xcb_errors_context_t **ctx);
+
+/**
+ * Freed the @ref xcb_cursor_context_t.
+ *
+ * @param ctx The context to free.
+ */
+void xcb_errors_context_free(xcb_errors_context_t *ctx);
+
+/**
+ * Get the name corresponding to some major code.
+ *
+ * @param ctx An errors context, created with @ref xcb_errors_context_new ()
+ * @param major_code The major code
+ * @return A string allocated in static storage that contains a name for this
+ * major code. This will never return NULL, but other functions in this library
+ * may.
+ */
+const char *xcb_errors_get_name_for_major_code(xcb_errors_context_t *ctx,
+		uint8_t major_code);
+
+/**
+ * Get the name corresponding to some minor code or NULL.
+ *
+ * @param ctx An errors context, created with @ref xcb_errors_context_new ()
+ * @param major_code The major code under which to look up the minor code
+ * @param major_code The minor code
+ * @return A string allocated in static storage that contains a name for this
+ * major code or NULL.
+ */
+const char *xcb_errors_get_name_for_minor_code(xcb_errors_context_t *ctx,
+		uint8_t major_code,
+		uint16_t minor_code);
+
+/**
+ * Get the name corresponding to some event.
+ *
+ * @param ctx An errors context, created with @ref xcb_errors_context_new ()
+ * @param event_code The response_type of an event.
+ * @return A string allocated in static storage that contains a name for this
+ * major code. This will never return NULL, but other functions in this library
+ * may.
+ */
+const char *xcb_errors_get_name_for_event(xcb_errors_context_t *ctx,
+		uint8_t event_code);
+
+/**
+ * Get the name corresponding to some error.
+ *
+ * @param ctx An errors context, created with @ref xcb_errors_context_new ()
+ * @param error_code The error_code of an error reply.
+ * @return A string allocated in static storage that contains a name for this
+ * major code. This will never return NULL, but other functions in this library
+ * may.
+ */
+const char *xcb_errors_get_name_for_error(xcb_errors_context_t *ctx,
+		uint8_t error_code);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __XCB_ERRORS_H__ */