14 files changed, 237 insertions, 3 deletions
diff --git a/Help/release/dev/GNUInstallDirs-special-prefixes.rst b/Help/release/dev/GNUInstallDirs-special-prefixes.rst
new file mode 100644
index 0000000..83c1352
--- /dev/null
+++ b/Help/release/dev/GNUInstallDirs-special-prefixes.rst
@@ -0,0 +1,9 @@
+GNUInstallDirs-special-prefixes
+-------------------------------
+
+* The :module:`GNUInstallDirs` module learned special default values
+  for certain installation prefixes according to the `GNU Coding
+  Standards`_ and the `Filesystem Hierarchy Standard`_.
+
+.. _`GNU Coding Standards`: https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
+.. _`Filesystem Hierarchy Standard`: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/index.html
diff --git a/Modules/GNUInstallDirs.cmake b/Modules/GNUInstallDirs.cmake
index 82258d1..b42084e 100644
--- a/Modules/GNUInstallDirs.cmake
+++ b/Modules/GNUInstallDirs.cmake
@@ -9,6 +9,9 @@
 #
 # .. _`GNU Coding Standards`: https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
 #
+# Result Variables
+# ^^^^^^^^^^^^^^^^
+#
 # Inclusion of this module defines the following variables:
 #
 # ``CMAKE_INSTALL_<dir>``
@@ -22,7 +25,8 @@
 #   The absolute path generated from the corresponding ``CMAKE_INSTALL_<dir>``
 #   value.  If the value is not already an absolute path, an absolute path
 #   is constructed typically by prepending the value of the
-#   :variable:`CMAKE_INSTALL_PREFIX` variable.
+#   :variable:`CMAKE_INSTALL_PREFIX` variable.  However, there are some
+#   `special cases`_ as documented below.
 #
 # where ``<dir>`` is one of:
 #
@@ -60,8 +64,44 @@
 #
 # If the includer does not define a value the above-shown default will be
 # used and the value will appear in the cache for editing by the user.
+#
+# Special Cases
+# ^^^^^^^^^^^^^
+#
+# The following values of :variable:`CMAKE_INSTALL_PREFIX` are special:
+#
+# ``/``
+#
+#   For ``<dir>`` other than the ``SYSCONFDIR`` and ``LOCALSTATEDIR``,
+#   the value of ``CMAKE_INSTALL_<dir>`` is prefixed with ``usr/`` if
+#   it is not user-specified as an absolute path.  For example, the
+#   ``INCLUDEDIR`` value ``include`` becomes ``usr/include``.
+#   This is required by the `GNU Coding Standards`_, which state:
+#
+#     When building the complete GNU system, the prefix will be empty
+#     and ``/usr`` will be a symbolic link to ``/``.
+#
+# ``/usr``
+#
+#   For ``<dir>`` equal to ``SYSCONFDIR`` or ``LOCALSTATEDIR``, the
+#   ``CMAKE_INSTALL_FULL_<dir>`` is computed by prepending just ``/``
+#   to the value of ``CMAKE_INSTALL_<dir>`` if it is not user-specified
+#   as an absolute path.  For example, the ``SYSCONFDIR`` value ``etc``
+#   becomes ``/etc``.  This is required by the `GNU Coding Standards`_.
+#
+# ``/opt/...``
+#
+#   For ``<dir>`` equal to ``SYSCONFDIR`` or ``LOCALSTATEDIR``, the
+#   ``CMAKE_INSTALL_FULL_<dir>`` is computed by *appending* the prefix
+#   to the value of ``CMAKE_INSTALL_<dir>`` if it is not user-specified
+#   as an absolute path.  For example, the ``SYSCONFDIR`` value ``etc``
+#   becomes ``/etc/opt/...``.  This is defined by the
+#   `Filesystem Hierarchy Standard`_.
+#
+# .. _`Filesystem Hierarchy Standard`: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/index.html
 
 #=============================================================================
+# Copyright 2015 Alex Turbov <i.zaufi@gmail.com>
 # Copyright 2011 Nikita Krupen'ko <krnekit@gmail.com>
 # Copyright 2011 Kitware, Inc.
 #
@@ -279,8 +319,35 @@ foreach(dir
     MANDIR
     DOCDIR
     )
-  if(NOT IS_ABSOLUTE ${CMAKE_INSTALL_${dir}})
-    set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_${dir}}")
+  if(NOT IS_ABSOLUTE "${CMAKE_INSTALL_${dir}}")
+    # Handle special cases:
+    # - CMAKE_INSTALL_PREFIX == /
+    # - CMAKE_INSTALL_PREFIX == /usr
+    # - CMAKE_INSTALL_PREFIX == /opt/...
+    if("${CMAKE_INSTALL_PREFIX}" STREQUAL "/")
+      if("${dir}" STREQUAL "SYSCONFDIR" OR "${dir}" STREQUAL "LOCALSTATEDIR")
+        set(CMAKE_INSTALL_FULL_${dir} "/${CMAKE_INSTALL_${dir}}")
+      else()
+        if (NOT "${CMAKE_INSTALL_${dir}}" MATCHES "^usr/")
+          set(CMAKE_INSTALL_${dir} "usr/${CMAKE_INSTALL_${dir}}")
+        endif()
+        set(CMAKE_INSTALL_FULL_${dir} "/${CMAKE_INSTALL_${dir}}")
+      endif()
+    elseif("${CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
+      if("${dir}" STREQUAL "SYSCONFDIR" OR "${dir}" STREQUAL "LOCALSTATEDIR")
+        set(CMAKE_INSTALL_FULL_${dir} "/${CMAKE_INSTALL_${dir}}")
+      else()
+        set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_${dir}}")
+      endif()
+    elseif("${CMAKE_INSTALL_PREFIX}" MATCHES "^/opt/.*")
+      if("${dir}" STREQUAL "SYSCONFDIR" OR "${dir}" STREQUAL "LOCALSTATEDIR")
+        set(CMAKE_INSTALL_FULL_${dir} "/${CMAKE_INSTALL_${dir}}${CMAKE_INSTALL_PREFIX}")
+      else()
+        set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_${dir}}")
+      endif()
+    else()
+      set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_${dir}}")
+    endif()
   else()
     set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_${dir}}")
   endif()
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 4543908..bc706d3 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -128,6 +128,7 @@ add_RunCMake_test(FPHSA)
 add_RunCMake_test(GeneratorExpression)
 add_RunCMake_test(GeneratorPlatform)
 add_RunCMake_test(GeneratorToolset)
+add_RunCMake_test(GNUInstallDirs)
 add_RunCMake_test(TargetPropertyGeneratorExpressions)
 add_RunCMake_test(Languages)
 add_RunCMake_test(ObjectLibrary)
diff --git a/Tests/RunCMake/GNUInstallDirs/CMakeLists.txt b/Tests/RunCMake/GNUInstallDirs/CMakeLists.txt
new file mode 100644
index 0000000..74b3ff8
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.3)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/GNUInstallDirs/Common.cmake b/Tests/RunCMake/GNUInstallDirs/Common.cmake
new file mode 100644
index 0000000..eff2d54
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Common.cmake
@@ -0,0 +1,28 @@
+set(CMAKE_SIZEOF_VOID_P 8)
+set(CMAKE_LIBRARY_ARCHITECTURE "arch")
+if(CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
+  set(CMAKE_SYSTEM_NAME "OpenBSD-Fake")
+endif()
+include(GNUInstallDirs)
+set(dirs
+  BINDIR
+  DATADIR
+  DATAROOTDIR
+  DOCDIR
+  INCLUDEDIR
+  INFODIR
+  LIBDIR
+  LIBEXECDIR
+  LOCALEDIR
+  LOCALSTATEDIR
+  MANDIR
+  SBINDIR
+  SHAREDSTATEDIR
+  SYSCONFDIR
+  )
+foreach(dir ${dirs})
+  message("CMAKE_INSTALL_${dir}='${CMAKE_INSTALL_${dir}}'")
+endforeach()
+foreach(dir ${dirs})
+  message("CMAKE_INSTALL_FULL_${dir}='${CMAKE_INSTALL_FULL_${dir}}'")
+endforeach()
diff --git a/Tests/RunCMake/GNUInstallDirs/Opt-stderr.txt b/Tests/RunCMake/GNUInstallDirs/Opt-stderr.txt
new file mode 100644
index 0000000..aee8552
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Opt-stderr.txt
@@ -0,0 +1,28 @@
+^CMAKE_INSTALL_BINDIR='bin'
+CMAKE_INSTALL_DATADIR='share'
+CMAKE_INSTALL_DATAROOTDIR='share'
+CMAKE_INSTALL_DOCDIR='share/doc/Opt'
+CMAKE_INSTALL_INCLUDEDIR='include'
+CMAKE_INSTALL_INFODIR='share/info'
+CMAKE_INSTALL_LIBDIR='(lib|lib64)'
+CMAKE_INSTALL_LIBEXECDIR='libexec'
+CMAKE_INSTALL_LOCALEDIR='share/locale'
+CMAKE_INSTALL_LOCALSTATEDIR='var'
+CMAKE_INSTALL_MANDIR='share/man'
+CMAKE_INSTALL_SBINDIR='sbin'
+CMAKE_INSTALL_SHAREDSTATEDIR='com'
+CMAKE_INSTALL_SYSCONFDIR='etc'
+CMAKE_INSTALL_FULL_BINDIR='/opt/Opt/bin'
+CMAKE_INSTALL_FULL_DATADIR='/opt/Opt/share'
+CMAKE_INSTALL_FULL_DATAROOTDIR='/opt/Opt/share'
+CMAKE_INSTALL_FULL_DOCDIR='/opt/Opt/share/doc/Opt'
+CMAKE_INSTALL_FULL_INCLUDEDIR='/opt/Opt/include'
+CMAKE_INSTALL_FULL_INFODIR='/opt/Opt/share/info'
+CMAKE_INSTALL_FULL_LIBDIR='/opt/Opt/(lib|lib64)'
+CMAKE_INSTALL_FULL_LIBEXECDIR='/opt/Opt/libexec'
+CMAKE_INSTALL_FULL_LOCALEDIR='/opt/Opt/share/locale'
+CMAKE_INSTALL_FULL_LOCALSTATEDIR='/var/opt/Opt'
+CMAKE_INSTALL_FULL_MANDIR='/opt/Opt/share/man'
+CMAKE_INSTALL_FULL_SBINDIR='/opt/Opt/sbin'
+CMAKE_INSTALL_FULL_SHAREDSTATEDIR='/opt/Opt/com'
+CMAKE_INSTALL_FULL_SYSCONFDIR='/etc/opt/Opt'$
diff --git a/Tests/RunCMake/GNUInstallDirs/Opt.cmake b/Tests/RunCMake/GNUInstallDirs/Opt.cmake
new file mode 100644
index 0000000..49eab0e
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Opt.cmake
@@ -0,0 +1,2 @@
+set(CMAKE_INSTALL_PREFIX "/opt/${PROJECT_NAME}")
+include(Common.cmake)
diff --git a/Tests/RunCMake/GNUInstallDirs/Root-stderr.txt b/Tests/RunCMake/GNUInstallDirs/Root-stderr.txt
new file mode 100644
index 0000000..a95400e
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Root-stderr.txt
@@ -0,0 +1,28 @@
+^CMAKE_INSTALL_BINDIR='usr/bin'
+CMAKE_INSTALL_DATADIR='usr/share'
+CMAKE_INSTALL_DATAROOTDIR='usr/share'
+CMAKE_INSTALL_DOCDIR='usr/share/doc/Root'
+CMAKE_INSTALL_INCLUDEDIR='usr/include'
+CMAKE_INSTALL_INFODIR='usr/share/info'
+CMAKE_INSTALL_LIBDIR='usr/(lib|lib64)'
+CMAKE_INSTALL_LIBEXECDIR='usr/libexec'
+CMAKE_INSTALL_LOCALEDIR='usr/share/locale'
+CMAKE_INSTALL_LOCALSTATEDIR='var'
+CMAKE_INSTALL_MANDIR='usr/share/man'
+CMAKE_INSTALL_SBINDIR='usr/sbin'
+CMAKE_INSTALL_SHAREDSTATEDIR='usr/com'
+CMAKE_INSTALL_SYSCONFDIR='etc'
+CMAKE_INSTALL_FULL_BINDIR='/usr/bin'
+CMAKE_INSTALL_FULL_DATADIR='/usr/share'
+CMAKE_INSTALL_FULL_DATAROOTDIR='/usr/share'
+CMAKE_INSTALL_FULL_DOCDIR='/usr/share/doc/Root'
+CMAKE_INSTALL_FULL_INCLUDEDIR='/usr/include'
+CMAKE_INSTALL_FULL_INFODIR='/usr/share/info'
+CMAKE_INSTALL_FULL_LIBDIR='/usr/(lib|lib64)'
+CMAKE_INSTALL_FULL_LIBEXECDIR='/usr/libexec'
+CMAKE_INSTALL_FULL_LOCALEDIR='/usr/share/locale'
+CMAKE_INSTALL_FULL_LOCALSTATEDIR='/var'
+CMAKE_INSTALL_FULL_MANDIR='/usr/share/man'
+CMAKE_INSTALL_FULL_SBINDIR='/usr/sbin'
+CMAKE_INSTALL_FULL_SHAREDSTATEDIR='/usr/com'
+CMAKE_INSTALL_FULL_SYSCONFDIR='/etc'$
diff --git a/Tests/RunCMake/GNUInstallDirs/Root.cmake b/Tests/RunCMake/GNUInstallDirs/Root.cmake
new file mode 100644
index 0000000..f8cc641
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Root.cmake
@@ -0,0 +1,2 @@
+set(CMAKE_INSTALL_PREFIX "/")
+include(Common.cmake)
diff --git a/Tests/RunCMake/GNUInstallDirs/RunCMakeTest.cmake b/Tests/RunCMake/GNUInstallDirs/RunCMakeTest.cmake
new file mode 100644
index 0000000..f88569a
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/RunCMakeTest.cmake
@@ -0,0 +1,6 @@
+include(RunCMake)
+
+run_cmake(Opt)
+run_cmake(Root)
+run_cmake(Usr)
+run_cmake(UsrLocal)
diff --git a/Tests/RunCMake/GNUInstallDirs/Usr-stderr.txt b/Tests/RunCMake/GNUInstallDirs/Usr-stderr.txt
new file mode 100644
index 0000000..e10c4c5
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Usr-stderr.txt
@@ -0,0 +1,28 @@
+^CMAKE_INSTALL_BINDIR='bin'
+CMAKE_INSTALL_DATADIR='share'
+CMAKE_INSTALL_DATAROOTDIR='share'
+CMAKE_INSTALL_DOCDIR='share/doc/Usr'
+CMAKE_INSTALL_INCLUDEDIR='include'
+CMAKE_INSTALL_INFODIR='share/info'
+CMAKE_INSTALL_LIBDIR='(lib|lib64|lib/arch)'
+CMAKE_INSTALL_LIBEXECDIR='libexec'
+CMAKE_INSTALL_LOCALEDIR='share/locale'
+CMAKE_INSTALL_LOCALSTATEDIR='var'
+CMAKE_INSTALL_MANDIR='share/man'
+CMAKE_INSTALL_SBINDIR='sbin'
+CMAKE_INSTALL_SHAREDSTATEDIR='com'
+CMAKE_INSTALL_SYSCONFDIR='etc'
+CMAKE_INSTALL_FULL_BINDIR='/usr/bin'
+CMAKE_INSTALL_FULL_DATADIR='/usr/share'
+CMAKE_INSTALL_FULL_DATAROOTDIR='/usr/share'
+CMAKE_INSTALL_FULL_DOCDIR='/usr/share/doc/Usr'
+CMAKE_INSTALL_FULL_INCLUDEDIR='/usr/include'
+CMAKE_INSTALL_FULL_INFODIR='/usr/share/info'
+CMAKE_INSTALL_FULL_LIBDIR='/usr/(lib|lib64|lib/arch)'
+CMAKE_INSTALL_FULL_LIBEXECDIR='/usr/libexec'
+CMAKE_INSTALL_FULL_LOCALEDIR='/usr/share/locale'
+CMAKE_INSTALL_FULL_LOCALSTATEDIR='/var'
+CMAKE_INSTALL_FULL_MANDIR='/usr/share/man'
+CMAKE_INSTALL_FULL_SBINDIR='/usr/sbin'
+CMAKE_INSTALL_FULL_SHAREDSTATEDIR='/usr/com'
+CMAKE_INSTALL_FULL_SYSCONFDIR='/etc'$
diff --git a/Tests/RunCMake/GNUInstallDirs/Usr.cmake b/Tests/RunCMake/GNUInstallDirs/Usr.cmake
new file mode 100644
index 0000000..62b7288
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/Usr.cmake
@@ -0,0 +1,2 @@
+set(CMAKE_INSTALL_PREFIX "/usr")
+include(Common.cmake)
diff --git a/Tests/RunCMake/GNUInstallDirs/UsrLocal-stderr.txt b/Tests/RunCMake/GNUInstallDirs/UsrLocal-stderr.txt
new file mode 100644
index 0000000..8dcf25b
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/UsrLocal-stderr.txt
@@ -0,0 +1,28 @@
+^CMAKE_INSTALL_BINDIR='bin'
+CMAKE_INSTALL_DATADIR='share'
+CMAKE_INSTALL_DATAROOTDIR='share'
+CMAKE_INSTALL_DOCDIR='share/doc/UsrLocal'
+CMAKE_INSTALL_INCLUDEDIR='include'
+CMAKE_INSTALL_INFODIR='share/info'
+CMAKE_INSTALL_LIBDIR='(lib|lib64)'
+CMAKE_INSTALL_LIBEXECDIR='libexec'
+CMAKE_INSTALL_LOCALEDIR='share/locale'
+CMAKE_INSTALL_LOCALSTATEDIR='var'
+CMAKE_INSTALL_MANDIR='share/man'
+CMAKE_INSTALL_SBINDIR='sbin'
+CMAKE_INSTALL_SHAREDSTATEDIR='com'
+CMAKE_INSTALL_SYSCONFDIR='etc'
+CMAKE_INSTALL_FULL_BINDIR='/usr/local/bin'
+CMAKE_INSTALL_FULL_DATADIR='/usr/local/share'
+CMAKE_INSTALL_FULL_DATAROOTDIR='/usr/local/share'
+CMAKE_INSTALL_FULL_DOCDIR='/usr/local/share/doc/UsrLocal'
+CMAKE_INSTALL_FULL_INCLUDEDIR='/usr/local/include'
+CMAKE_INSTALL_FULL_INFODIR='/usr/local/share/info'
+CMAKE_INSTALL_FULL_LIBDIR='/usr/local/(lib|lib64)'
+CMAKE_INSTALL_FULL_LIBEXECDIR='/usr/local/libexec'
+CMAKE_INSTALL_FULL_LOCALEDIR='/usr/local/share/locale'
+CMAKE_INSTALL_FULL_LOCALSTATEDIR='/usr/local/var'
+CMAKE_INSTALL_FULL_MANDIR='/usr/local/share/man'
+CMAKE_INSTALL_FULL_SBINDIR='/usr/local/sbin'
+CMAKE_INSTALL_FULL_SHAREDSTATEDIR='/usr/local/com'
+CMAKE_INSTALL_FULL_SYSCONFDIR='/usr/local/etc'$
diff --git a/Tests/RunCMake/GNUInstallDirs/UsrLocal.cmake b/Tests/RunCMake/GNUInstallDirs/UsrLocal.cmake
new file mode 100644
index 0000000..59d9331
--- /dev/null
+++ b/Tests/RunCMake/GNUInstallDirs/UsrLocal.cmake
@@ -0,0 +1,2 @@
+set(CMAKE_INSTALL_PREFIX "/usr/local")
+include(Common.cmake)