Move metadata into its own file (#3939)

Move `Metadata`, `MetadataLoweringError` and `ArchiveMetadata` into
their own file `metadata.rs` in `uv-distribution`, moving it out from
`lib.rs`. No functional changes.

crates/uv-distribution/src/lib.rs

@@ -1,20 +1,11 @@
-use std::collections::BTreeMap;
-use std::path::Path;
-
-use thiserror::Error;
-
-use archive::Archive;
 pub use distribution_database::{DistributionDatabase, HttpArchivePointer, LocalArchivePointer};
 pub use download::LocalWheel;
 pub use error::Error;
 pub use git::{git_url_to_precise, is_same_reference};
 pub use index::{BuiltWheelIndex, RegistryWheelIndex};
-use pep440_rs::{Version, VersionSpecifiers};
-use pypi_types::{HashDigest, Metadata23};
+pub use metadata::{ArchiveMetadata, Metadata};
 pub use reporter::Reporter;
-use requirement_lowering::{lower_requirement, LoweringError};
-use uv_configuration::PreviewMode;
-use uv_normalize::{ExtraName, PackageName};
+use requirement_lowering::LoweringError;
 pub use workspace::{ProjectWorkspace, Workspace, WorkspaceError, WorkspaceMember};
 
 mod archive;
@@ -24,133 +15,9 @@ mod error;
 mod git;
 mod index;
 mod locks;
+mod metadata;
 pub mod pyproject;
 mod reporter;
 mod requirement_lowering;
 mod source;
 mod workspace;
-
-#[derive(Debug, Error)]
-pub enum MetadataLoweringError {
-    #[error(transparent)]
-    Workspace(#[from] WorkspaceError),
-    #[error("Failed to parse entry for: `{0}`")]
-    LoweringError(PackageName, #[source] LoweringError),
-}
-
-#[derive(Debug, Clone)]
-pub struct Metadata {
-    // Mandatory fields
-    pub name: PackageName,
-    pub version: Version,
-    // Optional fields
-    pub requires_dist: Vec<pypi_types::Requirement>,
-    pub requires_python: Option<VersionSpecifiers>,
-    pub provides_extras: Vec<ExtraName>,
-}
-
-impl Metadata {
-    /// Lower without considering `tool.uv` in `pyproject.toml`, used for index and other archive
-    /// dependencies.
-    pub fn from_metadata23(metadata: Metadata23) -> Self {
-        Self {
-            name: metadata.name,
-            version: metadata.version,
-            requires_dist: metadata
-                .requires_dist
-                .into_iter()
-                .map(pypi_types::Requirement::from)
-                .collect(),
-            requires_python: metadata.requires_python,
-            provides_extras: metadata.provides_extras,
-        }
-    }
-
-    /// Lower by considering `tool.uv` in `pyproject.toml` if present, used for Git and directory
-    /// dependencies.
-    pub async fn from_workspace(
-        metadata: Metadata23,
-        project_root: &Path,
-        preview_mode: PreviewMode,
-    ) -> Result<Self, MetadataLoweringError> {
-        // TODO(konsti): Limit discovery for Git checkouts to Git root.
-        // TODO(konsti): Cache workspace discovery.
-        let Some(project_workspace) =
-            ProjectWorkspace::from_maybe_project_root(project_root, None).await?
-        else {
-            return Ok(Self::from_metadata23(metadata));
-        };
-
-        Self::from_project_workspace(metadata, &project_workspace, preview_mode)
-    }
-
-    pub fn from_project_workspace(
-        metadata: Metadata23,
-        project_workspace: &ProjectWorkspace,
-        preview_mode: PreviewMode,
-    ) -> Result<Metadata, MetadataLoweringError> {
-        let empty = BTreeMap::default();
-        let sources = project_workspace
-            .current_project()
-            .pyproject_toml()
-            .tool
-            .as_ref()
-            .and_then(|tool| tool.uv.as_ref())
-            .and_then(|uv| uv.sources.as_ref())
-            .unwrap_or(&empty);
-
-        let requires_dist = metadata
-            .requires_dist
-            .into_iter()
-            .map(|requirement| {
-                let requirement_name = requirement.name.clone();
-                lower_requirement(
-                    requirement,
-                    &metadata.name,
-                    project_workspace.project_root(),
-                    sources,
-                    project_workspace.workspace(),
-                    preview_mode,
-                )
-                .map_err(|err| MetadataLoweringError::LoweringError(requirement_name.clone(), err))
-            })
-            .collect::<Result<_, _>>()?;
-
-        Ok(Self {
-            name: metadata.name,
-            version: metadata.version,
-            requires_dist,
-            requires_python: metadata.requires_python,
-            provides_extras: metadata.provides_extras,
-        })
-    }
-}
-
-/// The metadata associated with an archive.
-#[derive(Debug, Clone)]
-pub struct ArchiveMetadata {
-    /// The [`Metadata`] for the underlying distribution.
-    pub metadata: Metadata,
-    /// The hashes of the source or built archive.
-    pub hashes: Vec<HashDigest>,
-}
-
-impl ArchiveMetadata {
-    /// Lower without considering `tool.uv` in `pyproject.toml`, used for index and other archive
-    /// dependencies.
-    pub fn from_metadata23(metadata: Metadata23) -> Self {
-        Self {
-            metadata: Metadata::from_metadata23(metadata),
-            hashes: vec![],
-        }
-    }
-}
-
-impl From<Metadata> for ArchiveMetadata {
-    fn from(metadata: Metadata) -> Self {
-        Self {
-            metadata,
-            hashes: vec![],
-        }
-    }
-}