build-system: Add 'meson-build-system'.

* Makefile.am (MODULES): Add 'guix/build-system/meson.scm' and
'guix/build/meson-build-system.scm'.
* guix/build-system/meson.scm: New file.
* guix/build/meson-build-system.scm: New file.
* doc/guix.texi (Build Systems): Add 'meson-build-system'.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

4 files changed, 385 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index a2fb313916..e35bdac306 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -79,6 +79,7 @@ MODULES =					\
   guix/build-system/dub.scm			\
   guix/build-system/emacs.scm			\
   guix/build-system/font.scm			\
+  guix/build-system/meson.scm			\
   guix/build-system/minify.scm			\
   guix/build-system/asdf.scm			\
   guix/build-system/glib-or-gtk.scm		\
@@ -106,6 +107,7 @@ MODULES =					\
   guix/build/cmake-build-system.scm		\
   guix/build/dub-build-system.scm		\
   guix/build/emacs-build-system.scm		\
+  guix/build/meson-build-system.scm		\
   guix/build/minify-build-system.scm		\
   guix/build/font-build-system.scm		\
   guix/build/asdf-build-system.scm		\
diff --git a/doc/guix.texi b/doc/guix.texi
index ebeef50709..1356a357cc 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -3811,6 +3811,61 @@ need to be copied into place.  It copies font files to standard
 locations in the output directory.
 @end defvr
 
+@defvr {Scheme Variable} meson-build-system
+This variable is exported by @code{(guix build-system meson)}.  It
+implements the build procedure for packages that use
+@url{http://mesonbuild.com, Meson} as their build system.
+
+It adds both Meson and @uref{https://ninja-build.org/, Ninja} to the set
+of inputs, and they can be changed with the parameters @code{#:meson}
+and @code{#:ninja} if needed.  The default Meson is
+@code{meson-for-build}, which is special because it doesn't clear the
+@code{RUNPATH} of binaries and libraries when they are installed.
+
+This build system is an extension of @var{gnu-build-system}, but with the
+following phases changed to some specific for Meson:
+
+@table @code
+
+@item configure
+The phase runs @code{meson} with the flags specified in
+@code{#:configure-flags}.  The flag @code{--build-type} is always set to
+@code{plain} unless something else is specified in @code{#:build-type}.
+
+@item build
+The phase runs @code{ninja} to build the package in parallel by default, but
+this can be changed with @code{#:parallel-build?}.
+
+@item check
+The phase runs @code{ninja} with the target specified in @code{#:test-target},
+which is @code{"test"} by default.
+
+@item install
+The phase runs @code{ninja install} and can not be changed.
+@end table
+
+Apart from that, the build system also adds the following phases:
+
+@table @code
+
+@item fix-runpath
+This phase tries to locate the local directories in the package being build,
+which has libraries that some of the binaries need.  If any are found, they will
+be added to the programs @code{RUNPATH}.  It is needed because
+@code{meson-for-build} keeps the @code{RUNPATH} of binaries and libraries from
+when they are build, but often that is not the @code{RUNPATH} we want.
+Therefor it is also shrinked to the minimum needed by the program.
+
+@item glib-or-gtk-wrap
+This phase is the phase provided by @code{glib-or-gtk-build-system}, and it
+is not enabled by default.  It can be enabled with @code{#:glib-or-gtk?}.
+
+@item glib-or-gtk-compile-schemas
+This phase is the phase provided by @code{glib-or-gtk-build-system}, and it
+is not enabled by default.  It can be enabled with @code{#:glib-or-gtk?}.
+@end table
+@end defvr
+
 Lastly, for packages that do not need anything as sophisticated, a
 ``trivial'' build system is provided.  It is trivial in the sense that
 it provides basically no support: it does not pull any implicit inputs,
diff --git a/guix/build-system/meson.scm b/guix/build-system/meson.scm
new file mode 100644
index 0000000000..d66ec760a4
--- /dev/null
+++ b/guix/build-system/meson.scm
@@ -0,0 +1,178 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 Peter Mikkelsen <petermikkelsen10@gmail.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix 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.
+;;;
+;;; GNU Guix 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build-system meson)
+  #:use-module (guix store)
+  #:use-module (guix utils)
+  #:use-module (guix derivations)
+  #:use-module (guix search-paths)
+  #:use-module (guix build-system)
+  #:use-module (guix build-system gnu)
+  #:use-module (guix build-system glib-or-gtk)
+  #:use-module (guix packages)
+  #:use-module (ice-9 match)
+  #:export (%meson-build-system-modules
+            meson-build-system))
+
+;; Commentary:
+;;
+;; Standard build procedure for packages using Meson. This is implemented as an
+;; extension of `gnu-build-system', with the option to turn on the glib/gtk
+;; phases from `glib-or-gtk-build-system'.
+;;
+;; Code:
+
+(define %meson-build-system-modules
+  ;; Build-side modules imported by default.
+  `((guix build meson-build-system)
+    (guix build rpath)
+    ;; The modules from glib-or-gtk contains the modules from gnu-build-system,
+    ;; so there is no need to import that too.
+    ,@%glib-or-gtk-build-system-modules))
+
+(define (default-ninja)
+  "Return the default ninja package."
+  ;; Lazily resolve the binding to avoid a circular dependency.
+  (let ((module (resolve-interface '(gnu packages ninja))))
+    (module-ref module 'ninja)))
+
+(define (default-meson)
+  "Return the default meson package."
+  ;; Lazily resolve the binding to avoid a circular dependency.
+  (let ((module (resolve-interface '(gnu packages build-tools))))
+    (module-ref module 'meson-for-build)))
+
+(define (default-patchelf)
+  "Return the default patchelf package."
+  ;; Lazily resolve the binding to avoid a circular dependency.
+  (let ((module (resolve-interface '(gnu packages elf))))
+    (module-ref module 'patchelf)))
+
+(define* (lower name
+                #:key source inputs native-inputs outputs system target
+                (meson (default-meson))
+                (ninja (default-ninja))
+                (glib-or-gtk #f)
+                #:allow-other-keys
+                #:rest arguments)
+  "Return a bag for NAME."
+  (define private-keywords
+    `(#:source #:meson #:ninja #:inputs #:native-inputs #:outputs #:target))
+
+  (and (not target) ;; TODO: add support for cross-compilation.
+       (bag
+         (name name)
+         (system system)
+         (build-inputs `(("meson" ,meson)
+                         ("ninja" ,ninja)
+                         ;; Add patchelf for (guix build rpath) to work.
+                         ("patchelf" ,(default-patchelf))
+                         ,@native-inputs))
+         (host-inputs `(,@(if source
+                              `(("source" ,source))
+                              '())
+                        ,@inputs
+                        ;; Keep the standard inputs of 'gnu-build-system'.
+                        ,@(standard-packages)))
+         (outputs outputs)
+         (build meson-build)
+         (arguments (strip-keyword-arguments private-keywords arguments)))))
+
+(define* (meson-build store name inputs
+                      #:key (guile #f)
+                      (outputs '("out"))
+                      (configure-flags ''())
+                      (search-paths '())
+                      (build-type "plain")
+                      (tests? #t)
+                      (test-target "test")
+                      (glib-or-gtk? #f)
+                      (parallel-build? #t)
+                      (parallel-tests? #f)
+                      (validate-runpath? #t)
+                      (patch-shebangs? #t)
+                      (strip-binaries? #t)
+                      (strip-flags ''("--strip-debug"))
+                      (strip-directories ''("lib" "lib64" "libexec"
+                                            "bin" "sbin"))
+                      (elf-directories ''("lib" "lib64" "libexec"
+                                          "bin" "sbin"))
+                      (phases '(@ (guix build meson-build-system)
+                                  %standard-phases))
+                      (system (%current-system))
+                      (imported-modules %meson-build-system-modules)
+                      (modules '((guix build meson-build-system)
+                                 (guix build utils))))
+  "Build SOURCE using MESON, and with INPUTS, assuming that SOURCE
+has a 'meson.build' file."
+  (define builder
+    `(let ((build-phases (if ,glib-or-gtk?
+                             ,phases
+                             (modify-phases ,phases
+                               (delete 'glib-or-gtk-compile-schemas)
+                               (delete 'glib-or-gtk-wrap)))))
+       (use-modules ,@modules)
+       (meson-build #:source ,(match (assoc-ref inputs "source")
+                                (((? derivation? source))
+                                 (derivation->output-path source))
+                                ((source)
+                                 source)
+                                (source
+                                 source))
+                    #:system ,system
+                    #:outputs %outputs
+                    #:inputs %build-inputs
+                    #:search-paths ',(map search-path-specification->sexp
+                                          search-paths)
+                    #:phases build-phases
+                    #:configure-flags ,configure-flags
+                    #:build-type ,build-type
+                    #:tests? ,tests?
+                    #:test-target ,test-target
+                    #:parallel-build? ,parallel-build?
+                    #:parallel-tests? ,parallel-tests?
+                    #:validate-runpath? ,validate-runpath?
+                    #:patch-shebangs? ,patch-shebangs?
+                    #:strip-binaries? ,strip-binaries?
+                    #:strip-flags ,strip-flags
+                    #:strip-directories ,strip-directories
+                    #:elf-directories ,elf-directories)))
+
+  (define guile-for-build
+    (match guile
+      ((? package?)
+       (package-derivation store guile system #:graft? #f))
+      (#f                                         ; the default
+       (let* ((distro (resolve-interface '(gnu packages commencement)))
+              (guile  (module-ref distro 'guile-final)))
+         (package-derivation store guile system #:graft? #f)))))
+
+  (build-expression->derivation store name builder
+                                #:system system
+                                #:inputs inputs
+                                #:modules imported-modules
+                                #:outputs outputs
+                                #:guile-for-build guile-for-build))
+
+(define meson-build-system
+  (build-system
+    (name 'meson)
+    (description "The standard Meson build system")
+    (lower lower)))
+
+;;; meson.scm ends here
diff --git a/guix/build/meson-build-system.scm b/guix/build/meson-build-system.scm
new file mode 100644
index 0000000000..2b92240c52
--- /dev/null
+++ b/guix/build/meson-build-system.scm
@@ -0,0 +1,150 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 Peter Mikkelsen <petermikkelsen10@gmail.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix 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.
+;;;
+;;; GNU Guix 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix build meson-build-system)
+  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
+  #:use-module ((guix build glib-or-gtk-build-system) #:prefix glib-or-gtk:)
+  #:use-module (guix build utils)
+  #:use-module (guix build rpath)
+  #:use-module (guix build gremlin)
+  #:use-module (guix elf)
+  #:use-module (ice-9 match)
+  #:use-module (rnrs io ports)
+  #:use-module (srfi srfi-1)
+  #:export (%standard-phases
+            meson-build))
+
+;; Commentary:
+;;
+;; Builder-side code of the standard meson build procedure.
+;;
+;; Code:
+
+(define* (configure #:key outputs configure-flags build-type
+                    #:allow-other-keys)
+  "Configure the given package."
+  (let* ((out (assoc-ref outputs "out"))
+         (source-dir (getcwd))
+         (build-dir "../build")
+         (prefix (assoc-ref outputs "out"))
+         (args `(,(string-append "--prefix=" prefix)
+                 ,(string-append "--buildtype=" build-type)
+                 ,@configure-flags
+                 ,source-dir)))
+    (mkdir build-dir)
+    (chdir build-dir)
+    (zero? (apply system* "meson" args))))
+
+(define* (build #:key parallel-build?
+                #:allow-other-keys)
+  "Build a given meson package."
+  (zero? (apply system* "ninja"
+                (if parallel-build?
+                    `("-j" ,(number->string (parallel-job-count)))
+                    '("-j" "1")))))
+
+(define* (check #:key test-target parallel-tests? tests?
+                #:allow-other-keys)
+  (setenv "MESON_TESTTHREADS"
+          (if parallel-tests?
+              (number->string (parallel-job-count))
+              "1"))
+  (if tests?
+      (zero? (system* "ninja" test-target))
+      (begin
+        (format #t "test suite not run~%")
+        #t)))
+
+(define* (install #:rest args)
+  (zero? (system* "ninja" "install")))
+
+(define* (fix-runpath #:key (elf-directories '("lib" "lib64" "libexec"
+                                               "bin" "sbin"))
+                      outputs #:allow-other-keys)
+  "Try to make sure all ELF files in ELF-DIRECTORIES are able to find their
+local dependencies in their RUNPATH, by searching for the needed libraries in
+the directories of the package, and adding them to the RUNPATH if needed.
+Also shrink the RUNPATH to what is needed,
+since a lot of directories are left over from the build phase of meson,
+for example libraries only needed for the tests."
+
+  ;; Find the directories (if any) that contains DEP-NAME.  The directories
+  ;; searched are the ones that ELF-FILES are in.
+  (define (find-deps dep-name elf-files)
+    (map dirname (filter (lambda (file)
+                           (string=? dep-name (basename file)))
+                         elf-files)))
+
+  ;; Return a list of libraries that FILE needs.
+  (define (file-needed file)
+    (let* ((elf (call-with-input-file file
+                  (compose parse-elf get-bytevector-all)))
+           (dyninfo (elf-dynamic-info elf)))
+      (if dyninfo
+          (elf-dynamic-info-needed dyninfo)
+          '())))
+
+
+  ;; If FILE needs any libs that are part of ELF-FILES, the RUNPATH
+  ;; is modified accordingly.
+  (define (handle-file file elf-files)
+    (let* ((dep-dirs (concatenate (map (lambda (dep-name)
+                                         (find-deps dep-name elf-files))
+                                       (file-needed file)))))
+      (unless (null? dep-dirs)
+        (augment-rpath file (string-join dep-dirs ":")))))
+
+  (define handle-output
+    (match-lambda
+      ((output . directory)
+       (let* ((elf-dirnames (map (lambda (subdir)
+                                   (string-append directory "/" subdir))
+                                 elf-directories))
+              (existing-elf-dirs (filter (lambda (dir)
+                                            (and (file-exists? dir)
+                                                 (file-is-directory? dir)))
+                                          elf-dirnames))
+              (elf-pred (lambda (name stat)
+                          (elf-file? name)))
+              (elf-list (concatenate (map (lambda (dir)
+                                            (find-files dir elf-pred))
+                                          existing-elf-dirs))))
+         (for-each (lambda (elf-file)
+                     (system* "patchelf" "--shrink-rpath" elf-file)
+                     (handle-file elf-file elf-list))
+                   elf-list)))))
+  (for-each handle-output outputs)
+  #t)
+
+(define %standard-phases
+  ;; The standard-phases of glib-or-gtk contains a superset of the phases
+  ;; from the gnu-build-system.  If the glib-or-gtk? key is #f (the default)
+  ;; then the extra phases will be removed again in (guix build-system meson).
+  (modify-phases glib-or-gtk:%standard-phases
+    (replace 'configure configure)
+    (replace 'build build)
+    (replace 'check check)
+    (replace 'install install)
+    (add-after 'strip 'fix-runpath fix-runpath)))
+
+(define* (meson-build #:key inputs phases
+                      #:allow-other-keys #:rest args)
+  "Build the given package, applying all of PHASES in order."
+  (apply gnu:gnu-build #:inputs inputs #:phases phases args))
+
+;;; meson-build-system.scm ends here