Copy and move (#38)

* rename, copy, performance updates

* oof

* remove unused ffi

* update changelog

* more changelog

Author: bcpeinhardt

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 
 ## Unreleased
+- Add `copy` function which can copy a file or a directory.
+- Deprecate `rename_file` and `rename_directory` in favor of `rename` which does both.
+- Refactor `copy_directory` to make fewer file system calls.
+- Add some helpful docs for creating symlinks.
 
 ## v2.1.0 - 28 August 2024
 - Add `FileInfo` and `file_info_type` to get the file type from a `FileInfo` without checking the file system again

src/simplifile.gleam

@@ -413,6 +413,9 @@ pub fn is_directory(filepath: String) -> Result(Bool, FileError)
 pub fn create_directory(filepath: String) -> Result(Nil, FileError)
 
 /// Create a symbolic link called symlink pointing to target.
+/// Footgun Alert: the target path is relative to *the symlink*,
+/// not the current working directory. I will likely be updating 
+/// the label on the next major version to reflect that.
 ///
 /// ## Example
 /// ```gleam
@@ -492,6 +495,24 @@ pub fn create_directory_all(dirpath: String) -> Result(Nil, FileError) {
 @external(javascript, "./simplifile_js.mjs", "createDirAll")
 fn do_create_dir_all(dirpath: String) -> Result(Nil, FileError)
 
+/// Copy a file or a directory to a new path. Copies directories recursively.
+/// Performance note: This function does work to determine if the src path
+/// points to a file or a directory. Consider using one of the the dedicated 
+/// functions `copy_file` or `copy_directory` if you already know which one you need.
+pub fn copy(src src: String, dest dest: String) -> Result(Nil, FileError) {
+  use src_info <- result.try(file_info(src))
+  case file_info_type(src_info) {
+    File -> copy_file(src, dest)
+    Directory -> copy_directory(src, dest)
+    Symlink ->
+      Error(Unknown(
+        "This is an internal bug where the `file_info` is somehow returning info about a simlink. Please file an issue on the simplifile repo.",
+      ))
+    Other ->
+      Error(Unknown("Unknown file type (not file, directory, or simlink)"))
+  }
+}
+
 /// Copy a file at a given path to another path.
 /// Note: destination should include the filename, not just the directory
 pub fn copy_file(at src: String, to dest: String) -> Result(Nil, FileError) {
@@ -505,10 +526,16 @@ fn do_copy_file(src: String, dest: String) -> Result(Int, FileError)
 
 /// Rename a file at a given path to another path.
 /// Note: destination should include the filename, not just the directory
+@deprecated("This function can move a file or a directory, so it's being renamed `rename`.")
 @external(erlang, "simplifile_erl", "rename_file")
 @external(javascript, "./simplifile_js.mjs", "renameFile")
 pub fn rename_file(at src: String, to dest: String) -> Result(Nil, FileError)
 
+/// Rename a file or directory.
+@external(erlang, "simplifile_erl", "rename_file")
+@external(javascript, "./simplifile_js.mjs", "renameFile")
+pub fn rename(at src: String, to dest: String) -> Result(Nil, FileError)
+
 /// Copy a directory recursively
 pub fn copy_directory(at src: String, to dest: String) -> Result(Nil, FileError) {
   // Erlang does not provide a built in `copy_dir` function,
@@ -526,31 +553,34 @@ fn do_copy_directory(src: String, dest: String) -> Result(Nil, FileError) {
     let src_path = filepath.join(src, segment)
     let dest_path = filepath.join(dest, segment)
 
-    case is_file(src_path), is_directory(src_path) {
-      Ok(True), Ok(False) -> {
+    use src_info <- result.try(file_info(src_path))
+    case file_info_type(src_info) {
+      File -> {
         // For a file, create the file in the new directory
         use content <- result.try(read_bits(src_path))
         content
         |> write_bits(to: dest_path)
       }
-      Ok(False), Ok(True) -> {
+      Directory -> {
         // Create the target directory and recurse
         use _ <- result.try(create_directory(dest_path))
         do_copy_directory(src_path, dest_path)
       }
-      Error(e), _ | _, Error(e) -> {
-        Error(e)
-      }
-      Ok(False), Ok(False) | Ok(True), Ok(True) -> {
-        // We're really not sure how that one happened.
-        Error(Unknown("Unknown error copying directory"))
-      }
+      // Theoretically this shouldn't happen, as the file info function
+      // will follow a simlink.
+      Symlink ->
+        Error(Unknown(
+          "This is an internal bug where the `file_info` is somehow returning info about a simlink. Please file an issue on the simplifile repo.",
+        ))
+      Other ->
+        Error(Unknown("Unknown file type (not file, directory, or simlink)"))
     }
   })
   Ok(Nil)
 }
 
 /// Copy a directory recursively and then delete the old one.
+@deprecated("Use the `rename` function, which can rename a file or a directory.")
 pub fn rename_directory(
   at src: String,
   to dest: String,

test/simplifile_test.gleam

@@ -10,12 +10,12 @@ import simplifile.{
   Enomem, Enospc, Enosr, Enostr, Enosys, Enotblk, Enotdir, Enotsup, Enxio,
   Eopnotsupp, Eoverflow, Eperm, Epipe, Erange, Erofs, Espipe, Esrch, Estale,
   Etxtbsy, Exdev, Execute, File, FilePermissions, NotUtf8, Read, Unknown, Write,
-  append, append_bits, copy_directory, copy_file, create_directory,
+  append, append_bits, copy, copy_directory, copy_file, create_directory,
   create_directory_all, create_file, create_symlink, delete, delete_all,
   file_info, file_info_permissions, file_info_permissions_octal, file_info_type,
   file_permissions_to_octal, get_files, is_directory, is_file, is_symlink,
-  link_info, read, read_bits, read_directory, rename_directory, rename_file,
-  set_permissions, set_permissions_octal, write, write_bits,
+  link_info, read, read_bits, read_directory, rename, set_permissions,
+  set_permissions_octal, write, write_bits,
 }
 
 pub fn main() {
@@ -224,7 +224,7 @@ pub fn copy_test() {
 pub fn rename_test() {
   let assert Ok(_) = write("Hello", to: "./tmp/to_be_renamed.txt")
   let assert Ok(Nil) =
-    rename_file("./tmp/to_be_renamed.txt", to: "./tmp/renamed.txt")
+    rename("./tmp/to_be_renamed.txt", to: "./tmp/renamed.txt")
   let assert Ok(False) = is_file("./tmp/to_be_renamed.txt")
   let assert Ok(True) = is_file("./tmp/renamed.txt")
   let assert Ok(_) = delete("./tmp/renamed.txt")
@@ -266,8 +266,7 @@ pub fn rename_directory_test() {
     |> write(to: "./tmp/to_be_copied_dir/nested_dir/file.txt")
 
   // Copy the directory
-  let assert Ok(_) =
-    rename_directory("./tmp/to_be_copied_dir", to: "./tmp/copied_dir")
+  let assert Ok(_) = rename("./tmp/to_be_copied_dir", to: "./tmp/copied_dir")
 
   // Assert the contents are correct
   let assert Ok("Hello") = read("./tmp/copied_dir/file.txt")
@@ -546,8 +545,6 @@ pub fn link_info_test() {
   |> should.not_equal(6)
 }
 
-/// I visually inspected this info to make sure it matched on all targets.
-/// TODO: Add a better test setup for validating file info functionality.
 pub fn clear_directory_test() {
   let assert Ok(_) = create_directory_all("./tmp/clear_dir")
   let assert Ok(_) = create_directory_all("./tmp/clear_dir/nested_dir")
@@ -672,3 +669,59 @@ pub fn describe_error_test() {
   let assert "Unknown error: Something went wrong" =
     simplifile.describe_error(Unknown("Something went wrong"))
 }
+
+pub fn file_info_follows_simlinks_recursively_test() {
+  let assert Ok(_) = create_file("./tmp/base.txt")
+  let assert Ok(_) = create_symlink(from: "./tmp/layer_1.txt", to: "./base.txt")
+  let assert Ok(_) =
+    create_symlink(from: "./tmp/layer_2.txt", to: "./layer_1.txt")
+
+  let assert Ok(fi) = file_info("./tmp/layer_2.txt")
+  fi |> file_info_type |> should.equal(File)
+
+  let assert Ok(_) = create_directory("./tmp/base_dir")
+  let assert Ok(_) = create_symlink(from: "./tmp/layer_1_dir", to: "./base_dir")
+  let assert Ok(_) =
+    create_symlink(from: "./tmp/layer_2_dir", to: "./layer_1_dir")
+
+  let assert Ok(fi) = file_info("./tmp/layer_2_dir")
+  fi |> file_info_type |> should.equal(Directory)
+}
+
+pub fn copy_can_copy_whatever_test() {
+  let og_file = "./tmp/toodaloofile.txt"
+  let og_dir = "./tmp/toodaloofile_dir"
+  let symlink_to_file = "./tmp/toodaloolink.txt"
+
+  let assert Ok(_) = write("Hello", to: og_file)
+  let assert Ok(_) = create_directory(og_dir)
+  let assert Ok(_) = write("Hello subfile", to: og_dir <> "/subfile.txt")
+  let assert Ok(_) =
+    create_symlink(from: symlink_to_file, to: "./toodaloofile.txt")
+
+  let assert Ok(_) = copy(og_file, "./tmp/toodaloo_copied.txt")
+  let assert Ok("Hello") = read("./tmp/toodaloo_copied.txt")
+
+  let assert Ok(_) = copy(og_dir, "./tmp/toodaloo_copied_dir")
+  let assert Ok(["subfile.txt"]) = read_directory("./tmp/toodaloo_copied_dir")
+  let assert Ok("Hello subfile") = read("./tmp/toodaloo_copied_dir/subfile.txt")
+
+  let assert Ok(_) = copy(symlink_to_file, "./tmp/copied_link.txt")
+  let assert Ok("Hello") = read("./tmp/copied_link.txt")
+}
+
+pub fn rename_file_succeeds_at_renaming_a_directory_test() {
+  // I am so dumb lol
+
+  let dir = "./tmp/i_am_a_dir"
+  let file = dir <> "/i_am_a_file.txt"
+  let assert Ok(_) = create_directory_all(dir)
+  let assert Ok(_) = write("Hello", to: file)
+  let new_dir = "./tmp/i_am_also_a_dir"
+
+  let assert Ok(_) = rename(at: dir, to: new_dir)
+
+  let assert Ok(fi) = file_info(new_dir)
+  fi |> file_info_type |> should.equal(Directory)
+  read(new_dir <> "/i_am_a_file.txt") |> should.be_ok |> should.equal("Hello")
+}