copying from old repo

3 files changed, 118 insertions, 0 deletions

diff --git a/extension/examples/filesystem/filesystem.py b/extension/examples/filesystem/filesystem.py
new file mode 100644
index 00000000..eb5c2043
--- /dev/null
+++ b/extension/examples/filesystem/filesystem.py
@@ -0,0 +1,45 @@
+from abc import ABC, abstractmethod
+from typing import List
+
+
+class FileSystem(ABC):
+    """An abstract filesystem that can read/write from a set of files."""
+    @abstractmethod
+    def read(self, path) -> str:
+        raise NotImplementedError
+
+    @abstractmethod
+    def readlines(self, path) -> List[str]:
+        raise NotImplementedError
+
+    @abstractmethod
+    def write(self, path, content):
+        raise NotImplementedError
+
+    @abstractmethod
+    def exists(self, path) -> bool:
+        raise NotImplementedError
+
+    @abstractmethod
+    def rename_file(self, filepath: str, new_filepath: str):
+        raise NotImplementedError
+
+    @abstractmethod
+    def walk(self, path: str) -> List[str]:
+        raise NotImplementedError
+
+    @abstractmethod
+    def rename_directory(self, path: str, new_path: str):
+        raise NotImplementedError
+
+    @abstractmethod
+    def delete_file(self, filepath: str):
+        raise NotImplementedError
+
+    @abstractmethod
+    def delete_directory(self, path: str):
+        raise NotImplementedError
+
+    @abstractmethod
+    def add_directory(self, path: str):
+        raise NotImplementedError
diff --git a/extension/examples/filesystem/real.py b/extension/examples/filesystem/real.py
new file mode 100644
index 00000000..ec7aa693
--- /dev/null
+++ b/extension/examples/filesystem/real.py
@@ -0,0 +1,34 @@
+import os
+from typing import List
+from filesystem.filesystem import FileSystem
+
+
+class RealFileSystem(FileSystem):
+    """A filesystem that reads/writes from the actual filesystem."""
+
+    def read(self, path) -> str:
+        with open(path, "r") as f:
+            return f.read()
+
+    def readlines(self, path) -> List[str]:
+        with open(path, "r") as f:
+            return f.readlines()
+
+    def write(self, path, content):
+        with open(path, "w") as f:
+            f.write(content)
+
+    def exists(self, path) -> bool:
+        return os.path.exists(path)
+
+    def rename_file(self, filepath: str, new_filepath: str):
+        os.rename(filepath, new_filepath)
+
+    def rename_directory(self, path: str, new_path: str):
+        os.rename(path, new_path)
+
+    def delete_file(self, filepath: str):
+        os.remove(filepath)
+
+    def add_directory(self, path: str):
+        os.makedirs(path)
diff --git a/extension/examples/filesystem/virtual.py b/extension/examples/filesystem/virtual.py
new file mode 100644
index 00000000..91a10e7d
--- /dev/null
+++ b/extension/examples/filesystem/virtual.py
@@ -0,0 +1,39 @@
+from typing import Dict, List
+from filesystem.filesystem import FileSystem
+
+
+class VirtualFileSystem(FileSystem):
+    """A simulated filesystem from a mapping of filepath to file contents."""
+    files: Dict[str, str]
+
+    def __init__(self, files: Dict[str, str]):
+        self.files = files
+
+    def read(self, path) -> str:
+        return self.files[path]
+
+    def readlines(self, path) -> List[str]:
+        return self.files[path].splitlines()
+
+    def write(self, path, content):
+        self.files[path] = content
+
+    def exists(self, path) -> bool:
+        return path in self.files
+
+    def rename_file(self, filepath: str, new_filepath: str):
+        self.files[new_filepath] = self.files[filepath]
+        del self.files[filepath]
+
+    def rename_directory(self, path: str, new_path: str):
+        for filepath in self.files:
+            if filepath.startswith(path):
+                new_filepath = new_path + filepath[len(path):]
+                self.files[new_filepath] = self.files[filepath]
+                del self.files[filepath]
+
+    def delete_file(self, filepath: str):
+        del self.files[filepath]
+
+    def add_directory(self, path: str):
+        pass