Add a fn to list all tags with a certain prefix

Author: rklaehn

src/rpc/client/tags.rs

@@ -11,6 +11,7 @@
 //!
 //! [`Client::delete`] can be used to delete a tag.
 use anyhow::Result;
+use bytes::Bytes;
 use futures_lite::{Stream, StreamExt};
 use quic_rpc::{client::BoxedConnector, Connector, RpcClient};
 use serde::{Deserialize, Serialize};
@@ -48,6 +49,15 @@ where
         Ok(stream.next().await.transpose()?)
     }
 
+    /// Lists all tags.
+    pub async fn list_prefix(&self, prefix: &[u8]) -> Result<impl Stream<Item = Result<TagInfo>>> {
+        let stream = self
+            .rpc
+            .server_streaming(ListRequest::prefix(Bytes::copy_from_slice(prefix).into()))
+            .await?;
+        Ok(stream.map(|res| res.map_err(anyhow::Error::from)))
+    }
+
     /// Lists all tags.
     pub async fn list(&self) -> Result<impl Stream<Item = Result<TagInfo>>> {
         let stream = self.rpc.server_streaming(ListRequest::all()).await?;

src/rpc/proto/tags.rs

@@ -6,7 +6,10 @@ use serde::{Deserialize, Serialize};
 
 use super::{RpcResult, RpcService};
 use crate::{
-    net_protocol::BatchId, rpc::client::tags::TagInfo, util::increment_vec, HashAndFormat, Tag,
+    net_protocol::BatchId,
+    rpc::client::tags::TagInfo,
+    util::{increment_vec, next_prefix},
+    HashAndFormat, Tag,
 };
 
 #[allow(missing_docs)]
@@ -83,6 +86,22 @@ pub struct ListRequest {
 }
 
 impl ListRequest {
+    /// List tags with a prefix
+    pub fn prefix(prefix: Tag) -> Self {
+        let mut to = prefix.0.to_vec();
+        let to = if next_prefix(&mut to) {
+            Some(Bytes::from(to).into())
+        } else {
+            None
+        };
+        Self {
+            raw: true,
+            hash_seq: true,
+            from: Some(prefix),
+            to,
+        }
+    }
+
     /// List a single tag
     pub fn single(name: Tag) -> Self {
         let mut next = name.0.to_vec();

src/util.rs

@@ -302,6 +302,21 @@ pub(crate) fn raw_outboard_size(size: u64) -> u64 {
     BaoTree::new(size, IROH_BLOCK_SIZE).outboard_size()
 }
 
+/// Given a prefix, increment it lexographically.
+///
+/// If the prefix is all FF, this will return false because there is no
+/// higher prefix than that.
+pub(crate) fn next_prefix(bytes: &mut [u8]) -> bool {
+    for byte in bytes.iter_mut().rev() {
+        if *byte < 255 {
+            *byte += 1;
+            return true;
+        }
+        *byte = 0;
+    }
+    false
+}
+
 /// Increment a byte vector, lexographically.
 pub(crate) fn increment_vec(bytes: &mut Vec<u8>) {
     for byte in bytes.iter_mut().rev() {