changes after initial rebase

src/action.rs

@@ -14,7 +14,7 @@ mod drop;
 mod drop_index;
 mod find;
 mod find_and_modify;
-pub mod gridfs;
+pub(crate) mod gridfs;
 mod insert_many;
 mod insert_one;
 mod list_collections;

src/action/gridfs.rs

@@ -1,7 +1,7 @@
 //! Action builders for gridfs.
 
 mod delete;
-mod download;
+pub mod download;
 mod drop;
 mod find;
 mod rename;

src/action/gridfs/download.rs

@@ -6,19 +6,43 @@ use crate::{
     gridfs::{
         FilesCollectionDocument,
         GridFsBucket,
+        GridFsDownloadByIdOptions,
         GridFsDownloadByNameOptions,
         GridFsDownloadStream,
     },
 };
 
+// TODO: Determine proper visibility, including parent modules.
+pub struct DownloadRange(pub Option<u64>, pub Option<u64>);
+
+fn create_download_range(start: Option<u64>, end: Option<u64>) -> Result<DownloadRange> {
+    match (start, end) {
+        (Some(start), Some(end)) => {
+            if start <= end {
+                Ok(DownloadRange(Some(start), Some(end)))
+            } else {
+                Err(
+                    ErrorKind::GridFs(GridFsErrorKind::InvalidPartialDownloadRange { start, end })
+                        .into(),
+                )
+            }
+        }
+        _ => Ok(DownloadRange(start, end)),
+    }
+}
+
 impl GridFsBucket {
     /// Opens and returns a [`GridFsDownloadStream`] from which the application can read
     /// the contents of the stored file specified by `id`.
     ///
     /// `await` will return d[`Result<GridFsDownloadStream>`].
     #[deeplink]
     pub fn open_download_stream(&self, id: Bson) -> OpenDownloadStream {
-        OpenDownloadStream { bucket: self, id }
+        OpenDownloadStream {
+            bucket: self,
+            id,
+            options: None,
+        }
     }
 
     /// Opens and returns a [`GridFsDownloadStream`] from which the application can read
@@ -129,15 +153,28 @@ impl crate::sync::gridfs::GridFsBucket {
 pub struct OpenDownloadStream<'a> {
     bucket: &'a GridFsBucket,
     id: Bson,
+    options: Option<GridFsDownloadByIdOptions>,
+}
+
+impl<'a> OpenDownloadStream<'a> {
+    option_setters! { options: GridFsDownloadByIdOptions;
+        start: u64,
+        end: u64,
+    }
 }
 
 #[action_impl(sync = crate::sync::gridfs::GridFsDownloadStream)]
 impl<'a> Action for OpenDownloadStream<'a> {
     type Future = OpenDownloadStreamFuture;
 
     async fn execute(self) -> Result<GridFsDownloadStream> {
+        let range = create_download_range(
+            self.options.as_ref().and_then(|options| options.start),
+            self.options.as_ref().and_then(|options| options.end),
+        )?;
+
         let file = self.bucket.find_file_by_id(&self.id).await?;
-        GridFsDownloadStream::new(file, self.bucket.chunks()).await
+        GridFsDownloadStream::new(file, self.bucket.chunks(), range).await
     }
 }
 
@@ -154,6 +191,8 @@ pub struct OpenDownloadStreamByName<'a> {
 impl<'a> OpenDownloadStreamByName<'a> {
     option_setters! { options: GridFsDownloadByNameOptions;
         revision: i32,
+        start: u64,
+        end: u64,
     }
 }
 
@@ -162,10 +201,15 @@ impl<'a> Action for OpenDownloadStreamByName<'a> {
     type Future = OpenDownloadStreamByNameFuture;
 
     async fn execute(self) -> Result<GridFsDownloadStream> {
+        let range = create_download_range(
+            self.options.as_ref().and_then(|options| options.start),
+            self.options.as_ref().and_then(|options| options.end),
+        )?;
+
         let file = self
             .bucket
             .find_file_by_name(&self.filename, self.options)
             .await?;
-        GridFsDownloadStream::new(file, self.bucket.chunks()).await
+        GridFsDownloadStream::new(file, self.bucket.chunks(), range).await
     }
 }

src/gridfs.rs

@@ -10,7 +10,7 @@ use serde::{Deserialize, Serialize};
 use serde_with::skip_serializing_none;
 
 use crate::{
-    bson::{doc, oid::ObjectId, Bson, DateTime, Document, RawBinaryRef},
+    bson::{oid::ObjectId, Bson, DateTime, Document, RawBinaryRef},
     checked::Checked,
     error::Error,
     options::{CollectionOptions, ReadConcern, SelectionCriteria, WriteConcern},