vala: Add consts/methods to retrieve and check library version

https://gitlab.gnome.org/GNOME/vala/issues/304

1 files changed, 123 insertions, 0 deletions

diff --git a/vala/valaversion.vala.in b/vala/valaversion.vala.in
new file mode 100644
index 000000000..6a3289d40
--- /dev/null
+++ b/vala/valaversion.vala.in
@@ -0,0 +1,123 @@
+/* valaversion.vala
+ *
+ * Copyright (C) 2018  Rico Tzschichholz
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 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
+ * Lesser General Public License for more details.
+
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+ *
+ * Author:
+ * 	Rico Tzschichholz <ricotz@ubuntu.com>
+ */
+
+namespace Vala {
+	/**
+	 * Like get_major_version, but from the headers used at application compile time,
+	 * rather than from the library linked against at application run time
+	 */
+	public const int MAJOR_VERSION = @VALA_MAJOR_VERSION@;
+	/**
+	 * Like get_minor_version, but from the headers used at application compile time,
+	 * rather than from the library linked against at application run time
+	 */
+	public const int MINOR_VERSION = @VALA_MINOR_VERSION@;
+	/**
+	 * Like get_micro_version, but from the headers used at application compile time,
+	 * rather than from the library linked against at application run time
+	 */
+	public const int MICRO_VERSION = @VALA_MICRO_VERSION@;
+
+	/**
+	 * The API version string
+	 */
+	public const string API_VERSION = "@API_VERSION@";
+
+	/**
+	 * The full build-version string generated by the build-system
+	 */
+	public const string BUILD_VERSION = "@PACKAGE_VERSION@";
+
+	/**
+	 * Returns the major version number of the vala library.
+	 *
+	 * This function is in the library, so it represents the GTK+
+	 * library your code is running against.
+	 *
+	 * @return the major version number of the vala library
+	 */
+	public uint get_major_version () {
+		return MAJOR_VERSION;
+	}
+
+	/**
+	 * Returns the minor version number of the vala library.
+	 *
+	 * This function is in the library, so it represents the vala
+	 * library your code is are running against.
+	 *
+	 * @return the minor version number of the vala library
+	 */
+	public uint get_minor_version () {
+		return MINOR_VERSION;
+	}
+
+	/**
+	 * Returns the micro version number of the vala library.
+	 *
+	 * This function is in the library, so it represents the vala
+	 * library your code is running against.
+	 *
+	 * @return the micro version number of the vala library
+	 */
+	public uint get_micro_version () {
+		return MICRO_VERSION;
+	}
+
+	/**
+	 * Returns the full build-version string of the vala library.
+	 *
+	 * This function is in the library, so it represents the vala
+	 * library your code is running against.
+	 *
+	 * @return the full build-version string of the vala library
+	 */
+	public unowned string get_build_version () {
+		return BUILD_VERSION;
+	}
+
+	/**
+	 * Checks that the vala library in use is compatible with the given version.
+	 *
+	 * This function is in the library, so it represents the vala
+	 * library your code is running against.
+	 *
+	 * @param required_major the required major version
+	 * @param required_minor the required minor version
+	 * @param required_micro the required micro version
+	 * @return null if the vala library is compatible with the given version,
+	 * or a string describing the version mismatch.
+	 */
+	public unowned string? check_version (uint required_major, uint required_minor, uint required_micro)
+	{
+		uint effective_micro = 100 * MINOR_VERSION + MICRO_VERSION;
+		uint required_effective_micro = 100 * required_minor + required_micro;
+
+		if (required_major > MAJOR_VERSION)
+			return "vala version too old (major mismatch)";
+
+		if (required_effective_micro > effective_micro)
+			return "vala version too old (micro mismatch)";
+
+		return null;
+	}
+}