add install_emptydir function

This replaces the absolute hack of using

```
install_subdir('nonexisting', install_dir: 'share')
```

which requires you to make sure you don't accidentally or deliberately
have a completely different directory with the same name in your source
tree that is full of files you don't want installed. It also avoids
splitting the name in two and listing them in the wrong order.

You can also set the install mode of each directory component by listing
them one at a time in order, and in fact create nested structures at
all.

Fixes #1604
Properly fixes #2904

1 files changed, 16 insertions, 2 deletions

diff --git a/mesonbuild/minstall.py b/mesonbuild/minstall.py
index 6284f95..7864742 100644
--- a/mesonbuild/minstall.py
+++ b/mesonbuild/minstall.py
@@ -25,7 +25,7 @@ import sys
 import typing as T
 
 from . import environment
-from .backend.backends import InstallData, InstallDataBase, TargetInstallData, ExecutableSerialisation
+from .backend.backends import InstallData, InstallDataBase, InstallEmptyDir, TargetInstallData, ExecutableSerialisation
 from .coredata import major_versions_differ, MesonVersionMismatchException
 from .coredata import version as coredata_version
 from .mesonlib import Popen_safe, RealPathAction, is_windows
@@ -370,7 +370,7 @@ class Installer:
             return run_exe(*args, **kwargs)
         return 0
 
-    def should_install(self, d: T.Union[TargetInstallData, InstallDataBase, ExecutableSerialisation]) -> bool:
+    def should_install(self, d: T.Union[TargetInstallData, InstallEmptyDir,  InstallDataBase, ExecutableSerialisation]) -> bool:
         if d.subproject and (d.subproject in self.skip_subprojects or '*' in self.skip_subprojects):
             return False
         if self.tags and d.tag not in self.tags:
@@ -531,6 +531,7 @@ class Installer:
                 self.install_targets(d, dm, destdir, fullprefix)
                 self.install_headers(d, dm, destdir, fullprefix)
                 self.install_man(d, dm, destdir, fullprefix)
+                self.install_emptydir(d, dm, destdir, fullprefix)
                 self.install_data(d, dm, destdir, fullprefix)
                 self.restore_selinux_contexts(destdir)
                 self.apply_ldconfig(destdir)
@@ -581,6 +582,19 @@ class Installer:
                 self.did_install_something = True
             self.set_mode(outfilename, m.install_mode, d.install_umask)
 
+    def install_emptydir(self, d: InstallData, dm: DirMaker, destdir: str, fullprefix: str) -> None:
+        for e in d.emptydir:
+            if not self.should_install(e):
+                continue
+            self.did_install_something = True
+            full_dst_dir = get_destdir_path(destdir, fullprefix, e.path)
+            self.log(f'Installing new directory {full_dst_dir}')
+            if os.path.isfile(full_dst_dir):
+                print(f'Tried to create directory {full_dst_dir} but a file of that name already exists.')
+                sys.exit(1)
+            dm.makedirs(full_dst_dir, exist_ok=True)
+            self.set_mode(full_dst_dir, e.install_mode, d.install_umask)
+
     def install_headers(self, d: InstallData, dm: DirMaker, destdir: str, fullprefix: str) -> None:
         for t in d.headers:
             if not self.should_install(t):