Handle desktop files using gettext

Starting from version 0.19, gettext has native capabilities to extract
from, and merge back translations in desktop files.

Hence, use xgettext to extract messages, and msgfmt to create a desktop
file with translations; because of this, there no more need to prefix
with underscore the keys to be translated.

Update the gettext required version in INSTALL.md.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Pino Toscano <ptoscano@redhat.com>

INSTALL.md

@@ -30,7 +30,7 @@ A detailed dependency list can be found in
 
 Minimum version requirements of major components:
 
-   - gettext
+   - gettext >= 0.19
    - python >= 3.4
    - gtk3 >= 3.22
    - libvirt-python >= 0.6.0

data/virt-manager.desktop.in

@@ -1,6 +1,6 @@
 [Desktop Entry]
-_Name=Virtual Machine Manager
-_Comment=Manage virtual machines
+Name=Virtual Machine Manager
+Comment=Manage virtual machines
 Icon=virt-manager
 Exec=virt-manager
 Type=Application

setup.py

@@ -61,7 +61,7 @@ _appdata_files = [
 
 def _generate_meta_potfiles_in():
     potfiles = ""
-    for ignore, filelist in _desktop_files + _appdata_files:
+    for ignore, filelist in _appdata_files:
         potfiles += "\n".join(filelist) + "\n"
     return potfiles
 
@@ -107,9 +107,35 @@ class my_build_i18n(distutils.command.build.build):
             targetpath = os.path.join("share/locale", lang, "LC_MESSAGES")
             self.distribution.data_files.append((targetpath, (mo_file,)))
 
+        # Merge .in with translations using gettext
+        for (file_set, switch) in [(_desktop_files, "--desktop")]:
+            for (target, files) in file_set:
+                build_target = os.path.join("build", target)
+                if not os.path.exists(build_target):
+                    os.makedirs(build_target)
+
+                files_merged = []
+                for f in files:
+                    if f.endswith(".in"):
+                        file_merged = os.path.basename(f[:-3])
+                    else:
+                        file_merged = os.path.basename(f)
+
+                    file_merged = os.path.join(build_target, file_merged)
+                    cmd = ["msgfmt", switch, "--template", f, "-d", po_dir,
+                           "-o", file_merged]
+                    mtime_merged = (os.path.exists(file_merged) and
+                                    os.path.getmtime(file_merged)) or 0
+                    mtime_file = os.path.getmtime(f)
+                    if (mtime_merged < max_po_mtime or
+                        mtime_merged < mtime_file):
+                        # Only build if output is older than input (.po,.in)
+                        self.spawn(cmd)
+                    files_merged.append(file_merged)
+                self.distribution.data_files.append((target, files_merged))
+
         # merge .in with translation
-        for (file_set, switch) in [(_desktop_files, "-d"),
-                                   (_appdata_files, "-x")]:
+        for (file_set, switch) in [(_appdata_files, "-x")]:
             for (target, files) in file_set:
                 build_target = os.path.join("build", target)
                 if not os.path.exists(build_target):
@@ -685,6 +711,11 @@ class ExtractMessages(distutils.core.Command):
         finally:
             os.unlink(potpath)
 
+        # Extract the messages from the desktop files
+        desktop_files = [f for sublist in _desktop_files for f in sublist[1]]
+        cmd = xgettext_args + ["-j", "-L", "Desktop"] + desktop_files
+        self.spawn(cmd)
+
         # Extract the messages from the Python sources
         py_sources = list(Path("virtManager").rglob("*.py"))
         py_sources += list(Path("virtinst").rglob("*.py"))