I dunno what I was doing.

addons/KiriPythonRPCWrapper/KiriPythonBuildWrangler.gd

@@ -207,25 +207,44 @@ func get_runtime_python_executable_godot_path() -> String:
 func get_runtime_python_executable_system_path() -> String:
 	return ProjectSettings.globalize_path(get_runtime_python_executable_godot_path())
 
+func get_cache_status() -> Dictionary:
+	var cache_status = {}
+	var cache_path_godot : String = _get_cache_path_godot()
+	var cache_status_filename : String = cache_path_godot.path_join(".completed_unpack")
+	if FileAccess.file_exists(cache_status_filename):
+		var cache_status_json : String = FileAccess.get_file_as_string(cache_status_filename)
+		cache_status = JSON.parse_string(cache_status_json)
+	return cache_status
+
+func write_cache_status(cache_status : Dictionary):
+	var cache_path_godot : String = _get_cache_path_godot()
+	var cache_status_filename : String = cache_path_godot.path_join(".completed_unpack")
+	var cache_status_json = JSON.stringify(cache_status)
+	var cache_status_file : FileAccess = FileAccess.open(cache_status_filename, FileAccess.WRITE)
+	cache_status_file.store_string(cache_status_json)
+	cache_status_file.close()
+
 func unpack_python(overwrite : bool = false):
 
 	var cache_path_godot : String = _get_cache_path_godot()
 
-	# FIXME: !!! THIS CAN END UP WITH PARTIAL INSTALLS !!!
-	# Check to see if the Python executable already exists. If it does, we might
-	# just skip unpacking.
-	var python_executable_expected_path : String = \
-		get_runtime_python_executable_godot_path()
-	if not overwrite:
-		if FileAccess.file_exists(python_executable_expected_path):
-			return
-
 	# Open archive.
 	var python_archive_path : String = _detect_archive_for_runtime()
 	var reader : KiriTARReader = KiriTARReader.new()
 	var err : Error = reader.open(python_archive_path)
 	assert(err == OK)
 
+	var cache_status_filename : String = cache_path_godot.path_join(".completed_unpack")
+
+	# Check to see if we've marked this as completely unpacked.
+	var tar_hash : String = reader.get_tar_hash()
+	var cache_status : Dictionary = get_cache_status()
+	if not overwrite:
+		if cache_status.has("completed_install_hash"):
+			if cache_status["completed_install_hash"] == tar_hash:
+				# This appears to already be completely unpacked.
+				return
+
 	# Get files.
 	var file_list : PackedStringArray = reader.get_files()
 
@@ -233,6 +252,11 @@ func unpack_python(overwrite : bool = false):
 	for relative_filename : String in file_list:
 		reader.unpack_file(cache_path_godot, relative_filename)
 
+	# Mark this as completely unpacked.
+	print("Writing unpacked marker.")
+	cache_status["completed_install_hash"] = tar_hash
+	write_cache_status(cache_status)
+
 # TODO: Clear cache function. Uninstall Python, etc.
 
 func get_extra_scripts_list() -> Array:

addons/KiriPythonRPCWrapper/KiriTARReader.gd

@@ -35,8 +35,10 @@ class TarFileRecord:
 	var type_indicator : String
 
 var _internal_file_list = []
+var _internal_file_list_indices = {} # Map filename -> index in _internal_file_list
 var _reader : ZIPReader = null
 var _tar_file_cache : PackedByteArray = []
+var _tar_file_hash : PackedByteArray = []
 
 func _load_record(record : TarFileRecord) -> PackedByteArray:
 	load_cache()
@@ -121,6 +123,9 @@ func get_files() -> PackedStringArray:
 		ret.append(record.filename)
 	return ret
 
+func get_tar_hash():
+	return _tar_file_hash.hex_encode()
+
 func open(path: String) -> Error:
 
 	assert(not _reader)
@@ -133,6 +138,14 @@ func open(path: String) -> Error:
 
 	load_cache()
 
+	# Hash it.
+	print("Computing tar hash...")
+	var hashing : HashingContext = HashingContext.new()
+	hashing.start(HashingContext.HASH_SHA256)
+	hashing.update(_tar_file_cache)
+	_tar_file_hash = hashing.finish()
+	print("Done computing tar hash.")
+
 	var tar_file_offset = 0
 	var zero_filled_record_count = 0
 	var zero_filled_record : PackedByteArray = []
@@ -242,6 +255,7 @@ func open(path: String) -> Error:
 				tar_record.link_destination = merged_paxheader["linkpath"]
 			
 			# Add it to our record list.
+			_internal_file_list_indices[tar_record.filename] = len(_internal_file_list)
 			_internal_file_list.append(tar_record)
 	
 	return OK
@@ -259,6 +273,12 @@ func read_file(path : String, case_sensitive : bool = true) -> PackedByteArray:
 
 	return []
 
+func _convert_permissions(tar_mode_str : String) -> FileAccess.UnixPermissionFlags:
+	# Okay so this turned out to be easier than I thought. Godot's
+	# UnixPermissionFlags line up with the actual permission bits in the tar.
+	return _octal_str_to_int(tar_mode_str)
+
+
 # Extract a file to a specific path. Sets permissions when possible, handles
 # symlinks and directories. Will extract to the dest_path plus the internal
 # relative path.
@@ -266,30 +286,58 @@ func read_file(path : String, case_sensitive : bool = true) -> PackedByteArray:
 # Example:
 #   dest_path: "foo/bar", filename: "butts/whatever/thingy.txt"
 #   extracts to: "foo/bar/butts/whatever/thingy.txt"
-func unpack_file(dest_path : String, filename : String, overwrite : bool = false):
+func unpack_file(dest_path : String, filename : String, force_overwrite : bool = false):
 	var full_dest_path : String = dest_path.path_join(filename)
 	DirAccess.make_dir_recursive_absolute(full_dest_path.get_base_dir())
 	
-	for record : TarFileRecord in _internal_file_list:
-		
-		if record.filename.is_absolute_path():
-			# hmmmmmmmmmmmmmm
-			assert(false)
-			continue
-		
-		if record.filename.simplify_path().begins_with(".."):
-			assert(false)
-			continue
+	assert(_internal_file_list_indices.has(filename))
+	var record : TarFileRecord = _internal_file_list[_internal_file_list_indices[filename]]
 
 	# FIXME: There are probably a million other ways to do directory
-		#        traversal attacks.
+	#        traversal attacks than just what we've checked for here.
+	if record.filename.is_absolute_path():
+		assert(false)
+		return
+	if record.filename.simplify_path().begins_with(".."):
+		assert(false)
+		return
 
-		if record.filename == filename:
+	var need_file_made : bool = true
+	var need_permission_update : bool = true
+	var exists_in_some_way : bool = FileAccess.file_exists(full_dest_path) || DirAccess.dir_exists_absolute(full_dest_path)
 
-			# FIXME: Somehow this is slower than just overwriting the file.
-			#        Awesome. /s
-			if overwrite == false and FileAccess.file_exists(full_dest_path):
-				continue
+	# Check to see if we need to make the dir/file/etc.
+	if force_overwrite == false:
+
+		if exists_in_some_way:
+
+			# Link exists. Don't overwrite.
+			if record.is_link:
+				#print("Skip (link exist): ", full_dest_path)
+				# FIXME: Check symlink destination?
+				need_file_made = false
+
+			if record.is_directory:
+				#print("Skip (dir exist):  ", full_dest_path)
+				need_file_made = false
+
+			# If the file is there and it's a complete file, then we're probably
+			# done. We can't check or set mtime through Godot's API, though.
+			var f : FileAccess = FileAccess.open(full_dest_path, FileAccess.READ)
+			if f.get_length() == record.file_size:
+				#print("Skip (file exist): ", full_dest_path)
+				need_file_made = false
+			f.close()
+
+	if not record.is_link and OS.get_name() != "Windows":
+		if FileAccess.file_exists(full_dest_path) || DirAccess.dir_exists_absolute(full_dest_path):
+			var existing_permissions : FileAccess.UnixPermissionFlags = FileAccess.get_unix_permissions(full_dest_path)
+			var wanted_permissions : FileAccess.UnixPermissionFlags = _convert_permissions(record.mode)
+			if existing_permissions == wanted_permissions:
+				need_permission_update = false
+				#print("Permission are fine: ", record.mode, " ", existing_permissions, " ", full_dest_path)
+			else:
+				print("Permission update needed on existing file: ", record.mode, " ", existing_permissions, " ", full_dest_path)
 
 	if record.is_link:
 
@@ -323,10 +371,10 @@ func unpack_file(dest_path : String, filename : String, overwrite : bool = false
 	# Set permissions (on normal OSes, not Windows). I don't think this
 	# applies to symlinks, though.
 	if not record.is_link:
+		if need_permission_update:
 			if OS.get_name() != "Windows":
-					var err = OS.execute("chmod", [
-						record.mode,
-						ProjectSettings.globalize_path(full_dest_path) ])
+				var err : Error = FileAccess.set_unix_permissions(
+					full_dest_path, _convert_permissions(record.mode))
 				assert(err != -1)
 
 #endregion

addons/KiriPythonRPCWrapper/TODO.md

@@ -11,14 +11,16 @@ Done:
 	x Remove xterm dependency, or make it like a debug-only thing.
 	x Test on WINE/Windows.
 	x First-time setup of requirements (pip, etc).
+	x Deal with interrupted setup operations
+		x We check for the python.exe file in a given setup location to see if
+		  we need to unpack stuff, but what if that exists but the setup was
+		  interrupted and we're missing files?
+	x Deal with bad state after interrupted unpacking operation
 
 The big ones:
 
-	- Deal with interrupted setup operations
-		- We check for the python.exe file in a given setup location to see if
-		  we need to unpack stuff, but what if that exists but the setup was
-		  interrupted and we're missing files?
+	- Add some kind of progress bar, or API for progress tracking, for the unpacking.
+	- Progress bar or API for progress tracking for pip installs.
+		- Maybe we should parse the pip requirements.txt and also set up an API for calling pip install.
 	- Documentation.
 		- how to use .kiri_export_python
-
-