interpreter: memoize result of validate_within_subproject

This saves about 1% of execution time; path manipulation is expensive.
About 1% more could be saved by avoiding usage of "foo in bar.parents",
which is an expensive way to say "bar.startswith(foo)".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 31 insertions, 20 deletions

diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index a118b3c59..dd91474eb 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -292,6 +292,7 @@ class Interpreter(InterpreterBase, HoldableObject):
         self.sanity_check_ast()
         self.builtin.update({'meson': MesonMain(self.build, self)})
         self.processed_buildfiles: T.Set[str] = set()
+        self.validated_cache: T.Set[str] = set()
         self.project_args_frozen = False
         self.global_args_frozen = False  # implies self.project_args_frozen
         self.subprojects: T.Dict[str, SubprojectHolder] = {}
@@ -3129,27 +3130,37 @@ class Interpreter(InterpreterBase, HoldableObject):
             # subproject files, as long as they are scheduled to be installed.
             if validate_installable_file(norm):
                 return
-        norm = Path(os.path.abspath(Path(srcdir, subdir, fname)))
-        if os.path.isdir(norm):
-            inputtype = 'directory'
-        else:
-            inputtype = 'file'
-        if InterpreterRuleRelaxation.ALLOW_BUILD_DIR_FILE_REFERENCES in self.relaxations and builddir in norm.parents:
-            return
-        if srcdir not in norm.parents:
-            # Grabbing files outside the source tree is ok.
-            # This is for vendor stuff like:
-            #
-            # /opt/vendorsdk/src/file_with_license_restrictions.c
-            return
-        project_root = Path(srcdir, self.root_subdir)
-        subproject_dir = project_root / self.subproject_dir
-        if norm == project_root:
+
+        def do_validate_within_subproject(norm: Path) -> None:
+            if os.path.isdir(norm):
+                inputtype = 'directory'
+            else:
+                inputtype = 'file'
+            if InterpreterRuleRelaxation.ALLOW_BUILD_DIR_FILE_REFERENCES in self.relaxations and builddir in norm.parents:
+                return
+            if srcdir not in norm.parents:
+                # Grabbing files outside the source tree is ok.
+                # This is for vendor stuff like:
+                #
+                # /opt/vendorsdk/src/file_with_license_restrictions.c
+                return
+            project_root = Path(srcdir, self.root_subdir)
+            subproject_dir = project_root / self.subproject_dir
+            if norm == project_root:
+                return
+            if project_root not in norm.parents:
+                raise InterpreterException(f'Sandbox violation: Tried to grab {inputtype} {norm.name} outside current (sub)project.')
+            if subproject_dir == norm or subproject_dir in norm.parents:
+                raise InterpreterException(f'Sandbox violation: Tried to grab {inputtype} {norm.name} from a nested subproject.')
+
+        fname = os.path.join(subdir, fname)
+        if fname in self.validated_cache:
             return
-        if project_root not in norm.parents:
-            raise InterpreterException(f'Sandbox violation: Tried to grab {inputtype} {norm.name} outside current (sub)project.')
-        if subproject_dir == norm or subproject_dir in norm.parents:
-            raise InterpreterException(f'Sandbox violation: Tried to grab {inputtype} {norm.name} from a nested subproject.')
+
+        # Use os.path.abspath() to eliminate .. segments, but do not resolve symlinks
+        norm = Path(os.path.abspath(Path(srcdir, fname)))
+        do_validate_within_subproject(norm)
+        self.validated_cache.add(fname)
 
     @T.overload
     def source_strings_to_files(self, sources: T.List['mesonlib.FileOrString'], strict: bool = True) -> T.List['mesonlib.File']: ...