feat: Implement public directory cp & more efficient copy for `Privat…

…eFile` (#319)

* Implement `cp` for public directories

* Implement leaner copy algorithms

* Write wasm bindings for public cp & tests

wnfs-wasm/src/fs/public/directory.rs

@@ -211,6 +211,30 @@ impl PublicDirectory {
         }))
     }
 
+    /// Copies a specific node to another location.
+    pub fn cp(
+        &self,
+        path_segments_from: &Array,
+        path_segments_to: &Array,
+        time: &Date,
+        store: BlockStore,
+    ) -> JsResult<Promise> {
+        let mut directory = Rc::clone(&self.0);
+        let store = ForeignBlockStore(store);
+        let time = DateTime::<Utc>::from(time);
+        let path_segments_from = utils::convert_path_segments(path_segments_from)?;
+        let path_segments_to = utils::convert_path_segments(path_segments_to)?;
+
+        Ok(future_to_promise(async move {
+            (&mut directory)
+                .cp(&path_segments_from, &path_segments_to, time, &store)
+                .await
+                .map_err(error("Cannot copy content between directories"))?;
+
+            Ok(utils::create_public_op_result(directory, JsValue::NULL)?)
+        }))
+    }
+
     /// Creates a new directory at the specified path.
     ///
     /// This method acts like `mkdir -p` in Unix because it creates intermediate directories if they do not exist.

wnfs-wasm/tests/public.spec.ts

@@ -225,6 +225,52 @@ test.describe("PublicDirectory", () => {
     expect(imagesContent[0].name).toEqual("cats");
   });
 
+  test("cp can copy content between directories", async ({ page }) => {
+    const [imagesContent, picturesContent] = await page.evaluate(async () => {
+      const {
+        wnfs: { PublicDirectory },
+        mock: { MemoryBlockStore, sampleCID },
+      } = await window.setup();
+
+      const time = new Date();
+      const store = new MemoryBlockStore();
+      const root = new PublicDirectory(time);
+
+      var { rootDir } = await root.write(
+        ["pictures", "cats", "luna.jpeg"],
+        sampleCID,
+        time,
+        store
+      );
+
+      var { rootDir } = await rootDir.write(
+        ["pictures", "cats", "tabby.png"],
+        sampleCID,
+        time,
+        store
+      );
+
+      var { rootDir } = await rootDir.mkdir(["images"], time, store);
+
+      var { rootDir } = await rootDir.cp(
+        ["pictures", "cats"],
+        ["images", "cats"],
+        time,
+        store
+      );
+
+      const imagesContent = await rootDir.ls(["images"], store);
+
+      const picturesContent = await rootDir.ls(["pictures"], store);
+
+      return [imagesContent, picturesContent];
+    });
+
+    expect(imagesContent.length).toEqual(1);
+    expect(picturesContent.length).toEqual(1);
+    expect(imagesContent[0].name).toEqual("cats");
+  });
+
   test("A PublicDirectory has the correct metadata", async ({ page }) => {
     const result = await page.evaluate(async () => {
       const {

wnfs/src/private/directory.rs

@@ -602,11 +602,9 @@ impl PrivateDirectory {
     ///        .await?;
     ///     // Clone the forest that was used to write the file
     ///     // Open the file mutably
-    ///     let file = {
-    ///         root_dir
-    ///             .open_file_mut(hello_py, true, Utc::now(), forest, store, rng)
-    ///             .await?
-    ///     };
+    ///     let file = root_dir
+    ///         .open_file_mut(hello_py, true, Utc::now(), forest, store, rng)
+    ///         .await?;
     ///     // Define the content that will replace what is already in the file
     ///     let new_file_content = b"print('hello world 2')";
     ///     // Set the contents of the file, waiting for result and expecting no errors
@@ -1204,7 +1202,7 @@ impl PrivateDirectory {
     ///         .await
     ///         .unwrap();
     ///
-    ///     let result = root_dir
+    ///     root_dir
     ///         .cp(
     ///             &["code".into(), "python".into(), "hello.py".into()],
     ///             &["code".into(), "hello.py".into()],

wnfs/src/private/file.rs

@@ -260,6 +260,56 @@ impl PrivateFile {
         })
     }
 
+    /// Create a copy of this file without re-encrypting the actual content
+    /// (if the ciphertext is external ciphertext), so this is really fast
+    /// even if the file contains gigabytes of data.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use anyhow::Result;
+    /// use std::rc::Rc;
+    /// use chrono::Utc;
+    /// use rand::thread_rng;
+    /// use wnfs::{
+    ///     private::{PrivateDirectory, PrivateFile, forest::{hamt::HamtForest, traits::PrivateForest}},
+    ///     common::{MemoryBlockStore, utils::get_random_bytes},
+    /// };
+    ///
+    /// #[async_std::main]
+    /// async fn main() -> Result<()> {
+    ///     let store = &MemoryBlockStore::new();
+    ///     let rng = &mut thread_rng();
+    ///     let forest = &mut Rc::new(HamtForest::new_rsa_2048(rng));
+    ///
+    ///     let file = PrivateFile::with_content(
+    ///         &forest.empty_name(),
+    ///         Utc::now(),
+    ///         get_random_bytes::<100>(rng).to_vec(),
+    ///         forest,
+    ///         store,
+    ///         rng,
+    ///     )
+    ///     .await?;
+    ///
+    ///     let root_dir = &mut Rc::new(PrivateDirectory::new(&forest.empty_name(), Utc::now(), rng));
+    ///
+    ///     let copy = root_dir
+    ///         .open_file_mut(&["some".into(), "copy.txt".into()], true, Utc::now(), forest, store, rng)
+    ///         .await?;
+    ///
+    ///     copy.copy_content_from(&file, Utc::now());
+    ///
+    ///     assert_eq!(file.get_content(forest, store).await?, copy.get_content(forest, store).await?);
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn copy_content_from(&mut self, other: &Self, time: DateTime<Utc>) {
+        self.content.metadata.upsert_mtime(time);
+        self.content.content = other.content.content.clone();
+    }
+
     /// Streams the content of a file as chunk of blocks.
     ///
     /// # Examples
@@ -663,24 +713,16 @@ impl PrivateFile {
     /// will update the name to be the sub-name of given parent name,
     /// so it inherits the write access rules from the new parent and
     /// resets the `persisted_as` pointer.
-    /// Will copy and re-encrypt all external content.
     pub(crate) async fn prepare_key_rotation(
         &mut self,
         parent_name: &Name,
-        forest: &mut impl PrivateForest,
-        store: &impl BlockStore,
         rng: &mut impl CryptoRngCore,
     ) -> Result<()> {
-        let content = self.get_content(forest, store).await?;
-
         self.header.inumber = NameSegment::new(rng);
         self.header.update_name(parent_name);
         self.header.reset_ratchet(rng);
         self.content.persisted_as = OnceCell::new();
 
-        let content = Self::prepare_content(&self.header.name, content, forest, store, rng).await?;
-        self.content.content = content;
-
         Ok(())
     }
 

wnfs/src/private/node/node.rs

@@ -123,9 +123,7 @@ impl PrivateNode {
         match self {
             Self::File(file_rc) => {
                 let file = Rc::make_mut(file_rc);
-
-                file.prepare_key_rotation(parent_name, forest, store, rng)
-                    .await?;
+                file.prepare_key_rotation(parent_name, rng).await?;
             }
             Self::Dir(dir_rc) => {
                 let dir = Rc::make_mut(dir_rc);

wnfs/src/public/directory.rs

@@ -656,6 +656,81 @@ impl PublicDirectory {
         Ok(())
     }
 
+    /// Copies a file or directory from one path to another.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use anyhow::Result;
+    /// use std::rc::Rc;
+    /// use libipld_core::cid::Cid;
+    /// use chrono::Utc;
+    /// use rand::thread_rng;
+    /// use wnfs::{
+    ///     public::PublicDirectory,
+    ///     common::{BlockStore, MemoryBlockStore},
+    /// };
+    ///
+    /// #[async_std::main]
+    /// async fn main() -> Result<()> {
+    ///     let dir = &mut Rc::new(PublicDirectory::new(Utc::now()));
+    ///     let store = &MemoryBlockStore::new();
+    ///
+    ///     dir
+    ///         .write(
+    ///             &["code".into(), "python".into(), "hello.py".into()],
+    ///             Cid::default(),
+    ///             Utc::now(),
+    ///             store
+    ///         )
+    ///         .await?;
+    ///
+    ///     dir
+    ///         .cp(
+    ///             &["code".into(), "python".into(), "hello.py".into()],
+    ///             &["code".into(), "hello.py".into()],
+    ///             Utc::now(),
+    ///             store
+    ///         )
+    ///         .await?;
+    ///
+    ///     let result = dir
+    ///         .ls(&["code".into()], store)
+    ///         .await?;
+    ///
+    ///     assert_eq!(result.len(), 2);
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub async fn cp(
+        self: &mut Rc<Self>,
+        path_segments_from: &[String],
+        path_segments_to: &[String],
+        time: DateTime<Utc>,
+        store: &impl BlockStore,
+    ) -> Result<()> {
+        let (path, filename) = utils::split_last(path_segments_to)?;
+        let Some(mut node) = self.get_node(path_segments_from, store).await?.cloned() else {
+            bail!(FsError::NotFound);
+        };
+
+        let SearchResult::Found(dir) = self.get_leaf_dir_mut(path, store).await? else {
+            bail!(FsError::NotFound);
+        };
+
+        ensure!(
+            !dir.userland.contains_key(filename),
+            FsError::FileAlreadyExists
+        );
+
+        node.upsert_mtime(time);
+
+        dir.userland.insert(filename.clone(), PublicLink::new(node));
+
+        Ok(())
+    }
+
     #[async_recursion(?Send)]
     /// Stores directory in provided block store.
     ///