i18n: use real build/install targets for gmo files

Don't just create a .PHONY target which runs a script that magically
generates files ninja doesn't know about. It results in untracked files,
and `meson install` has to run additional commands instead of copying
over files, and then cannot track them to uninstall them later.

I'm not even really sure why it was originally done via a proxy script,
most likely bad legacy design. This is after all one of the oldest
modules...

One side effect of this is that meson doesn't know how to rename
build.CustomTarget files on install (only data files are supported?),
and every file needs to be installed as "domainname.mo" so it must be
named that in-tree too. To prevent clashes, every locale gets its own
locale-specific subdirectory.

Once we are doing that anyway, we can output them to the actual
structure required by the gettext family of functions, and
bindtextdomain() can therefore point to this location if desired. This
might be useful for running localized programs from the build tree.

2 files changed, 23 insertions, 51 deletions

diff --git a/mesonbuild/modules/i18n.py b/mesonbuild/modules/i18n.py
index f10fdbe..6e841d0 100644
--- a/mesonbuild/modules/i18n.py
+++ b/mesonbuild/modules/i18n.py
@@ -17,6 +17,7 @@ import shutil
 from os import path
 from .. import coredata, mesonlib, build, mlog
 from ..mesonlib import MesonException
+from ..scripts.gettext import read_linguas
 from . import ModuleReturnValue
 from . import ExtensionModule
 from ..interpreterbase import permittedKwargs, FeatureNew, FeatureNewKwargs
@@ -141,6 +142,7 @@ class I18nModule(ExtensionModule):
         languages = mesonlib.stringlistify(kwargs.get('languages', []))
         datadirs = self._get_data_dirs(state, mesonlib.stringlistify(kwargs.get('data_dirs', [])))
         extra_args = mesonlib.stringlistify(kwargs.get('args', []))
+        targets = []
 
         preset = kwargs.pop('preset', None)
         if preset:
@@ -161,11 +163,27 @@ class I18nModule(ExtensionModule):
         if extra_args:
             potargs.append(extra_args)
         pottarget = build.RunTarget(packagename + '-pot', potargs, [], state.subdir, state.subproject)
+        targets.append(pottarget)
 
-        gmoargs = state.environment.get_build_command() + ['--internal', 'gettext', 'gen_gmo']
-        if lang_arg:
-            gmoargs.append(lang_arg)
-        gmotarget = build.RunTarget(packagename + '-gmo', gmoargs, [], state.subdir, state.subproject)
+        install = kwargs.get('install', True)
+        install_dir = kwargs.get('install_dir', state.environment.coredata.get_option(mesonlib.OptionKey('localedir')))
+        if not languages:
+            languages = read_linguas(path.join(state.environment.source_dir, state.subdir))
+        for l in languages:
+            po_file = mesonlib.File.from_source_file(state.environment.source_dir,
+                                                     state.subdir, l+'.po')
+            gmo_kwargs = {'command': ['msgfmt', '@INPUT@', '-o', '@OUTPUT@'],
+                          'input': po_file,
+                          'output': packagename+'.mo',
+                          'install': install,
+                          # We have multiple files all installed as packagename+'.mo' in different install subdirs.
+                          # What we really wanted to do, probably, is have a rename: kwarg, but that's not available
+                          # to custom_targets. Crude hack: set the build target's subdir manually.
+                          # Bonus: the build tree has something usable as an uninstalled bindtextdomain() target dir.
+                          'install_dir': path.join(install_dir, l, 'LC_MESSAGES'),
+                          }
+            gmotarget = build.CustomTarget(l+'.mo', path.join(state.subdir, l, 'LC_MESSAGES'), state.subproject, gmo_kwargs)
+            targets.append(gmotarget)
 
         updatepoargs = state.environment.get_build_command() + ['--internal', 'gettext', 'update_po', pkg_arg]
         if lang_arg:
@@ -175,21 +193,7 @@ class I18nModule(ExtensionModule):
         if extra_args:
             updatepoargs.append(extra_args)
         updatepotarget = build.RunTarget(packagename + '-update-po', updatepoargs, [], state.subdir, state.subproject)
-
-        targets = [pottarget, gmotarget, updatepotarget]
-
-        install = kwargs.get('install', True)
-        if install:
-            install_dir = kwargs.get('install_dir', state.environment.coredata.get_option(mesonlib.OptionKey('localedir')))
-            script = state.environment.get_build_command()
-            args = ['--internal', 'gettext', 'install',
-                    '--subdir=' + state.subdir,
-                    '--localedir=' + install_dir,
-                    pkg_arg]
-            if lang_arg:
-                args.append(lang_arg)
-            iscript = state.backend.get_executable_serialisation(script + args)
-            targets.append(iscript)
+        targets.append(updatepotarget)
 
         return ModuleReturnValue(None, targets)
 
diff --git a/mesonbuild/scripts/gettext.py b/mesonbuild/scripts/gettext.py
index b1ce6af..d6bd366 100644
--- a/mesonbuild/scripts/gettext.py
+++ b/mesonbuild/scripts/gettext.py
@@ -13,10 +13,8 @@
 # limitations under the License.
 
 import os
-import shutil
 import argparse
 import subprocess
-from . import destdir_join
 import typing as T
 
 parser = argparse.ArgumentParser()
@@ -61,12 +59,6 @@ def run_potgen(src_sub: str, pkgname: str, datadirs: str, args: T.List[str]) ->
                             '-D', os.environ['MESON_SOURCE_ROOT'], '-k_', '-o', ofile] + args,
                            env=child_env)
 
-def gen_gmo(src_sub: str, bld_sub: str, langs: T.List[str]) -> int:
-    for l in langs:
-        subprocess.check_call(['msgfmt', os.path.join(src_sub, l + '.po'),
-                               '-o', os.path.join(bld_sub, l + '.gmo')])
-    return 0
-
 def update_po(src_sub: str, pkgname: str, langs: T.List[str]) -> int:
     potfile = os.path.join(src_sub, pkgname + '.pot')
     for l in langs:
@@ -77,19 +69,6 @@ def update_po(src_sub: str, pkgname: str, langs: T.List[str]) -> int:
             subprocess.check_call(['msginit', '--input', potfile, '--output-file', pofile, '--locale', l, '--no-translator'])
     return 0
 
-def do_install(src_sub: str, bld_sub: str, dest: str, pkgname: str, langs: T.List[str]) -> int:
-    for l in langs:
-        srcfile = os.path.join(bld_sub, l + '.gmo')
-        outfile = os.path.join(dest, l, 'LC_MESSAGES',
-                               pkgname + '.mo')
-        tempfile = outfile + '.tmp'
-        os.makedirs(os.path.dirname(outfile), exist_ok=True)
-        shutil.copy2(srcfile, tempfile)
-        os.replace(tempfile, outfile)
-        if not os.getenv('MESON_INSTALL_QUIET', False):
-            print(f'Installing {srcfile} to {outfile}')
-    return 0
-
 def run(args: T.List[str]) -> int:
     options = parser.parse_args(args)
     subcmd = options.command
@@ -99,27 +78,16 @@ def run(args: T.List[str]) -> int:
     if options.subdir:
         subdir = options.subdir
     src_sub = os.path.join(os.environ['MESON_SOURCE_ROOT'], subdir)
-    bld_sub = os.path.join(os.environ['MESON_BUILD_ROOT'], subdir)
 
     if not langs:
         langs = read_linguas(src_sub)
 
     if subcmd == 'pot':
         return run_potgen(src_sub, options.pkgname, options.datadirs, extra_args)
-    elif subcmd == 'gen_gmo':
-        return gen_gmo(src_sub, bld_sub, langs)
     elif subcmd == 'update_po':
         if run_potgen(src_sub, options.pkgname, options.datadirs, extra_args) != 0:
             return 1
         return update_po(src_sub, options.pkgname, langs)
-    elif subcmd == 'install':
-        destdir = os.environ.get('DESTDIR', '')
-        dest = destdir_join(destdir, os.path.join(os.environ['MESON_INSTALL_PREFIX'],
-                                                  options.localedir))
-        if gen_gmo(src_sub, bld_sub, langs) != 0:
-            return 1
-        do_install(src_sub, bld_sub, dest, options.pkgname, langs)
     else:
         print('Unknown subcommand.')
         return 1
-    return 0