Use boxed slices for hash vector (#11714)

## Summary

We never resize these, and they're stored everywhere (on `File`, etc.).
Seems useful to use a more efficient structure for them.

Author: charliermarsh

crates/uv-client/src/flat_index.rs

@@ -9,6 +9,7 @@ use uv_cache::{Cache, CacheBucket};
 use uv_cache_key::cache_digest;
 use uv_distribution_filename::DistFilename;
 use uv_distribution_types::{File, FileLocation, IndexUrl, UrlString};
+use uv_pypi_types::HashDigests;
 
 use crate::cached_client::{CacheControl, CachedClientError};
 use crate::html::SimpleHtml;
@@ -283,7 +284,7 @@ impl<'a> FlatIndexClient<'a> {
             let file = File {
                 dist_info_metadata: false,
                 filename: filename.to_string(),
-                hashes: Vec::new(),
+                hashes: HashDigests::empty(),
                 requires_python: None,
                 size: None,
                 upload_time_utc_ms: None,

crates/uv-distribution-types/src/cached.rs

@@ -3,7 +3,7 @@ use std::path::{Path, PathBuf};
 use uv_cache_info::CacheInfo;
 use uv_distribution_filename::WheelFilename;
 use uv_normalize::PackageName;
-use uv_pypi_types::{HashDigest, VerbatimParsedUrl};
+use uv_pypi_types::{HashDigest, HashDigests, VerbatimParsedUrl};
 
 use crate::{
     BuiltDist, Dist, DistributionMetadata, Hashed, InstalledMetadata, InstalledVersion, Name,
@@ -23,7 +23,7 @@ pub enum CachedDist {
 pub struct CachedRegistryDist {
     pub filename: WheelFilename,
     pub path: PathBuf,
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
     pub cache_info: CacheInfo,
 }
 
@@ -32,7 +32,7 @@ pub struct CachedDirectUrlDist {
     pub filename: WheelFilename,
     pub url: VerbatimParsedUrl,
     pub path: PathBuf,
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
     pub cache_info: CacheInfo,
 }
 
@@ -41,7 +41,7 @@ impl CachedDist {
     pub fn from_remote(
         remote: Dist,
         filename: WheelFilename,
-        hashes: Vec<HashDigest>,
+        hashes: HashDigests,
         cache_info: CacheInfo,
         path: PathBuf,
     ) -> Self {
@@ -156,7 +156,7 @@ impl CachedDist {
 
 impl Hashed for CachedRegistryDist {
     fn hashes(&self) -> &[HashDigest] {
-        &self.hashes
+        self.hashes.as_slice()
     }
 }
 

crates/uv-distribution-types/src/file.rs

@@ -7,7 +7,7 @@ use url::Url;
 
 use uv_pep440::{VersionSpecifiers, VersionSpecifiersParseError};
 use uv_pep508::split_scheme;
-use uv_pypi_types::{CoreMetadata, HashDigest, Yanked};
+use uv_pypi_types::{CoreMetadata, HashDigests, Yanked};
 
 /// Error converting [`uv_pypi_types::File`] to [`distribution_type::File`].
 #[derive(Debug, thiserror::Error)]
@@ -24,7 +24,7 @@ pub enum FileConversionError {
 pub struct File {
     pub dist_info_metadata: bool,
     pub filename: String,
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
     pub requires_python: Option<VersionSpecifiers>,
     pub size: Option<u64>,
     // N.B. We don't use a Jiff timestamp here because it's a little
@@ -47,7 +47,7 @@ impl File {
                 .or(file.data_dist_info_metadata.as_ref())
                 .is_some_and(CoreMetadata::is_available),
             filename: file.filename,
-            hashes: file.hashes.into_digests(),
+            hashes: HashDigests::from(file.hashes),
             requires_python: file
                 .requires_python
                 .transpose()

crates/uv-distribution-types/src/lib.rs

@@ -1127,19 +1127,19 @@ impl Identifier for Url {
 
 impl Identifier for File {
     fn distribution_id(&self) -> DistributionId {
-        if let Some(hash) = self.hashes.first() {
-            DistributionId::Digest(hash.clone())
-        } else {
-            self.url.distribution_id()
-        }
+        self.hashes
+            .first()
+            .cloned()
+            .map(DistributionId::Digest)
+            .unwrap_or_else(|| self.url.distribution_id())
     }
 
     fn resource_id(&self) -> ResourceId {
-        if let Some(hash) = self.hashes.first() {
-            ResourceId::Digest(hash.clone())
-        } else {
-            self.url.resource_id()
-        }
+        self.hashes
+            .first()
+            .cloned()
+            .map(ResourceId::Digest)
+            .unwrap_or_else(|| self.url.resource_id())
     }
 }
 

crates/uv-distribution-types/src/resolution.rs

@@ -1,7 +1,7 @@
 use uv_distribution_filename::DistExtension;
 use uv_normalize::{ExtraName, GroupName, PackageName};
 use uv_pep508::MarkerTree;
-use uv_pypi_types::{HashDigest, RequirementSource};
+use uv_pypi_types::{HashDigest, HashDigests, RequirementSource};
 
 use crate::{BuiltDist, Diagnostic, Dist, Name, ResolvedDist, SourceDist};
 
@@ -183,7 +183,7 @@ pub enum Node {
     Root,
     Dist {
         dist: ResolvedDist,
-        hashes: Vec<HashDigest>,
+        hashes: HashDigests,
         install: bool,
     },
 }

crates/uv-distribution/src/archive.rs

@@ -1,21 +1,21 @@
 use uv_cache::{ArchiveId, Cache, ARCHIVE_VERSION};
 use uv_distribution_types::Hashed;
-use uv_pypi_types::HashDigest;
+use uv_pypi_types::{HashDigest, HashDigests};
 
 /// An archive (unzipped wheel) that exists in the local cache.
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct Archive {
     /// The unique ID of the entry in the wheel's archive bucket.
     pub id: ArchiveId,
     /// The computed hashes of the archive.
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
     /// The version of the archive bucket.
     pub version: u8,
 }
 
 impl Archive {
     /// Create a new [`Archive`] with the given ID and hashes.
-    pub(crate) fn new(id: ArchiveId, hashes: Vec<HashDigest>) -> Self {
+    pub(crate) fn new(id: ArchiveId, hashes: HashDigests) -> Self {
         Self {
             id,
             hashes,
@@ -31,6 +31,6 @@ impl Archive {
 
 impl Hashed for Archive {
     fn hashes(&self) -> &[HashDigest] {
-        &self.hashes
+        self.hashes.as_slice()
     }
 }

crates/uv-distribution/src/distribution_database.rs

@@ -26,7 +26,7 @@ use uv_distribution_types::{
 use uv_extract::hash::Hasher;
 use uv_fs::write_atomic;
 use uv_platform_tags::Tags;
-use uv_pypi_types::HashDigest;
+use uv_pypi_types::{HashDigest, HashDigests};
 use uv_types::{BuildContext, BuildStack};
 
 use crate::archive::Archive;
@@ -719,7 +719,7 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
                     })
                     .await??;
 
-                    vec![]
+                    HashDigests::empty()
                 } else {
                     // Create a hasher for each hash algorithm.
                     let algorithms = hashes.algorithms();
@@ -843,7 +843,10 @@ impl<'a, Context: BuildContext> DistributionDatabase<'a, Context> {
             })
         } else if hashes.is_none() {
             // Otherwise, unzip the wheel.
-            let archive = Archive::new(self.unzip_wheel(path, wheel_entry.path()).await?, vec![]);
+            let archive = Archive::new(
+                self.unzip_wheel(path, wheel_entry.path()).await?,
+                HashDigests::empty(),
+            );
 
             // Write the archive pointer to the cache.
             let pointer = LocalArchivePointer {

crates/uv-distribution/src/download.rs

@@ -4,7 +4,7 @@ use crate::Error;
 use uv_distribution_filename::WheelFilename;
 use uv_distribution_types::{CachedDist, Dist, Hashed};
 use uv_metadata::read_flat_wheel_metadata;
-use uv_pypi_types::{HashDigest, ResolutionMetadata};
+use uv_pypi_types::{HashDigest, HashDigests, ResolutionMetadata};
 
 use uv_cache_info::CacheInfo;
 
@@ -21,7 +21,7 @@ pub struct LocalWheel {
     /// The cache index of the wheel.
     pub(crate) cache: CacheInfo,
     /// The computed hashes of the wheel.
-    pub(crate) hashes: Vec<HashDigest>,
+    pub(crate) hashes: HashDigests,
 }
 
 impl LocalWheel {
@@ -49,7 +49,7 @@ impl LocalWheel {
 
 impl Hashed for LocalWheel {
     fn hashes(&self) -> &[HashDigest] {
-        &self.hashes
+        self.hashes.as_slice()
     }
 }
 

crates/uv-distribution/src/index/cached_wheel.rs

@@ -7,7 +7,7 @@ use uv_distribution_types::{
     CachedDirectUrlDist, CachedRegistryDist, DirectUrlSourceDist, DirectorySourceDist,
     GitSourceDist, Hashed, PathSourceDist,
 };
-use uv_pypi_types::{HashDigest, VerbatimParsedUrl};
+use uv_pypi_types::{HashDigest, HashDigests, VerbatimParsedUrl};
 
 use crate::archive::Archive;
 use crate::{HttpArchivePointer, LocalArchivePointer};
@@ -19,7 +19,7 @@ pub struct CachedWheel {
     /// The [`CacheEntry`] for the wheel.
     pub entry: CacheEntry,
     /// The [`HashDigest`]s for the wheel.
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
     /// The [`CacheInfo`] for the wheel.
     pub cache_info: CacheInfo,
 }
@@ -36,7 +36,7 @@ impl CachedWheel {
         // Convert to a cached wheel.
         let archive = cache.resolve_link(path).ok()?;
         let entry = CacheEntry::from_path(archive);
-        let hashes = Vec::new();
+        let hashes = HashDigests::empty();
         let cache_info = CacheInfo::default();
         Some(Self {
             filename,
@@ -186,6 +186,6 @@ impl CachedWheel {
 
 impl Hashed for CachedWheel {
     fn hashes(&self) -> &[HashDigest] {
-        &self.hashes
+        self.hashes.as_slice()
     }
 }

crates/uv-distribution/src/metadata/mod.rs

@@ -7,7 +7,7 @@ use uv_configuration::SourceStrategy;
 use uv_distribution_types::{GitSourceUrl, IndexLocations};
 use uv_normalize::{ExtraName, GroupName, PackageName};
 use uv_pep440::{Version, VersionSpecifiers};
-use uv_pypi_types::{HashDigest, ResolutionMetadata};
+use uv_pypi_types::{HashDigests, ResolutionMetadata};
 use uv_workspace::dependency_groups::DependencyGroupError;
 use uv_workspace::WorkspaceError;
 
@@ -122,7 +122,7 @@ pub struct ArchiveMetadata {
     /// The [`Metadata`] for the underlying distribution.
     pub metadata: Metadata,
     /// The hashes of the source or built archive.
-    pub hashes: Vec<HashDigest>,
+    pub hashes: HashDigests,
 }
 
 impl ArchiveMetadata {
@@ -131,12 +131,12 @@ impl ArchiveMetadata {
     pub fn from_metadata23(metadata: ResolutionMetadata) -> Self {
         Self {
             metadata: Metadata::from_metadata23(metadata),
-            hashes: vec![],
+            hashes: HashDigests::empty(),
         }
     }
 
     /// Create an [`ArchiveMetadata`] with the given metadata and hashes.
-    pub fn with_hashes(metadata: Metadata, hashes: Vec<HashDigest>) -> Self {
+    pub fn with_hashes(metadata: Metadata, hashes: HashDigests) -> Self {
         Self { metadata, hashes }
     }
 }
@@ -145,7 +145,7 @@ impl From<Metadata> for ArchiveMetadata {
     fn from(metadata: Metadata) -> Self {
         Self {
             metadata,
-            hashes: vec![],
+            hashes: HashDigests::empty(),
         }
     }
 }