1 files changed, 133 insertions, 0 deletions
diff --git a/src/lib/libgamma-error.c.gpp b/src/lib/libgamma-error.c.gpp
new file mode 100644
index 0000000..d443f74
--- /dev/null
+++ b/src/lib/libgamma-error.c.gpp
@@ -0,0 +1,133 @@
+/* -*- c -*- */
+/**
+ * libgamma — Display server abstraction layer for gamma ramp adjustments
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * 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 "libgamma-error.h"
+
+
+#include <stddef.h>
+#include <sys/types.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+
+
+£>set -u
+£>cd src/extract
+£>export PATH=".:${PATH}"
+
+
+
+/**
+ * Group that the user needs to be a member of if `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned.
+ */
+gid_t libgamma_group_gid = 0;
+
+/**
+ * Group that the user needs to be a member of if `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned,
+ * `NULL` if the name of the group `libgamma_group_gid` cannot be determined.
+ */
+const char* libgamma_group_name = NULL;
+
+
+
+/**
+ * Prints an error to stderr in a `perror` fashion,
+ * however this function will not translate the `libgamma`
+ * errors into human-readable strings, it will simply
+ * print the name of the error. If the value `error_code`
+ * is the value of `LIBGAMMA_ERRNO_SET`, `perror` will be
+ * used to print the current error stored in `errno`.
+ * If `error_code` is non-negative (an `errno` value`), that
+ * value will be stored in `errno` and `perror` will be
+ * used to print it. Additionally, if the `error_code` is
+ * the value of `LIBGAMMA_DEVICE_REQUIRE_GROUP` the
+ * required group will be printed with its numerical value
+ * and, if known, its name.
+ * 
+ * @param  name   The text to add at the beginning.
+ * @param  value  The error code, may be an `errno` value.
+ */
+void libgamma_perror(const char* name, int error_code)
+{
+  if (error_code >= 0)
+    {
+      errno = error_code;
+      perror(name);
+    }
+  else if (error_code == LIBGAMMA_ERRNO_SET)
+    perror(name);
+  else if (error_code == LIBGAMMA_DEVICE_REQUIRE_GROUP)
+    {
+      const char* error = libgamma_name_of_error(error_code);
+      long int gid = (long int)libgamma_group_gid;
+      if (libgamma_group_name == NULL)
+	fprintf(stderr, "%s: %s: %ld\n", name, error, gid);
+      else
+	fprintf(stderr, "%s: %s: %s (%lid)\n", name, error, libgamma_group_name, gid);
+    }
+  else if (error_code < LIBGAMMA_ERROR_MIN)
+    fprintf(stderr, "%s: (?)\n", name);
+  else
+    fprintf(stderr, "%s: %s\n", name, libgamma_name_of_error(error_code));
+}
+
+
+/**
+ * Returns the name of the definition associated with a `libgamma` error code.
+ * 
+ * @param   value  The error code.
+ * @return         The name of the definition associated with the error code,
+ *                 `NULL` if the error code does not exist. The return string
+ *                 should not be `free`:d.
+ */
+const char* libgamma_name_of_error(int value)
+{
+  static const char* error_names[] =
+    {
+£>for error in $(libgamma-error-extract --list); do
+      "£{error}",
+£>done
+    };
+  
+  if ((value < LIBGAMMA_ERROR_MIN) || (value >= 0))
+    return NULL;
+  
+  return error_names[-value - 1];
+}
+
+
+/**
+ * Return the value of a `libgamma` error definition refered to by name.
+ * 
+ * @param   name  The name of the definition associated with the error code.
+ * @return        The error code, zero if the name does is `NULL`
+ *                or does not refer to a `libgamma` error.
+ */
+int libgamma_value_of_error(const char* name)
+{
+  if (name == NULL)
+    return 0;
+  
+£>for error in $(libgamma-error-extract --list); do
+  if (!strcmp(name, "£{error}"))  return £{error};
+£>done
+  
+  return 0;
+}
+