refactor(forc-pkg): Abstract out source-related items from pkg (#…

…4168)

## Description

In anticipation of the upcoming ipfs support (#3926), this PR refactors
`forc-pkg` to more clearly separate out the "source" abstraction from
the rest of the pkg-handling logic.

We do so by creating a common interface for sources in the form of
traits for pinning and fetching. This should allow for adding in the
upcoming ipfs implementation (or future alternative source kind) in a
manner that doesn't further complicate the rest of package handling.

There is still room for further refactor of `pkg.rs`, but this should do
enough to clear the way for ipfs support and closes #3927.

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

Co-authored-by: Joshua Batty <joshpbatty@gmail.com>

forc-pkg/src/lib.rs

@@ -7,6 +7,7 @@
 pub mod lock;
 pub mod manifest;
 mod pkg;
+pub mod source;
 
 pub use lock::Lock;
 pub use manifest::{

forc-pkg/src/lock.rs

@@ -1,4 +1,4 @@
-use crate::{pkg, DepKind, Edge};
+use crate::{pkg, source, DepKind, Edge};
 use anyhow::{anyhow, Result};
 use forc_tracing::{println_green, println_red};
 use petgraph::{visit::EdgeRef, Direction};
@@ -60,10 +60,7 @@ impl PkgLock {
     pub fn from_node(graph: &pkg::Graph, node: pkg::NodeIx, disambiguate: &HashSet<&str>) -> Self {
         let pinned = &graph[node];
         let name = pinned.name.clone();
-        let version = match &pinned.source {
-            pkg::SourcePinned::Registry(reg) => Some(reg.source.version.clone()),
-            _ => None,
-        };
+        let version = pinned.source.semver();
         let source = pinned.source.to_string();
         // Collection of all dependencies, so this includes both contract-dependencies and
         // lib-dependencies
@@ -188,7 +185,7 @@ impl Lock {
             // required.
             let key = pkg.name_disambiguated(&disambiguate).into_owned();
             let name = pkg.name.clone();
-            let source: pkg::SourcePinned = pkg.source.parse().map_err(|e| {
+            let source: source::Pinned = pkg.source.parse().map_err(|e| {
                 anyhow!("invalid 'source' entry for package {} lock: {:?}", name, e)
             })?;
             let pkg = pkg::Pinned { name, source };
@@ -272,7 +269,7 @@ fn pkg_unique_string(name: &str, source: &str) -> String {
 fn pkg_dep_line(
     dep_name: Option<&str>,
     name: &str,
-    source: &pkg::SourcePinned,
+    source: &source::Pinned,
     dep_kind: &DepKind,
     disambiguate: bool,
 ) -> PkgDepLine {
@@ -369,7 +366,7 @@ where
 
 // Only includes source after the name for git sources for friendlier printing.
 fn name_or_git_unique_string(pkg: &PkgLock) -> Cow<str> {
-    match pkg.source.starts_with(pkg::SourceGitPinned::PREFIX) {
+    match pkg.source.starts_with(source::git::Pinned::PREFIX) {
         true => Cow::Owned(pkg.unique_string()),
         false => Cow::Borrowed(&pkg.name),
     }

forc-pkg/src/manifest.rs

@@ -872,3 +872,27 @@ impl std::ops::Deref for WorkspaceManifestFile {
         &self.manifest
     }
 }
+
+/// Attempt to find a `Forc.toml` with the given project name within the given directory.
+///
+/// Returns the path to the package on success, or `None` in the case it could not be found.
+pub fn find_within(dir: &Path, pkg_name: &str) -> Option<PathBuf> {
+    walkdir::WalkDir::new(dir)
+        .into_iter()
+        .filter_map(Result::ok)
+        .filter(|entry| entry.path().ends_with(constants::MANIFEST_FILE_NAME))
+        .find_map(|entry| {
+            let path = entry.path();
+            let manifest = PackageManifest::from_file(path).ok()?;
+            if manifest.project.name == pkg_name {
+                Some(path.to_path_buf())
+            } else {
+                None
+            }
+        })
+}
+
+/// The same as [find_within], but returns the package's project directory.
+pub fn find_dir_within(dir: &Path, pkg_name: &str) -> Option<PathBuf> {
+    find_within(dir, pkg_name).and_then(|path| path.parent().map(Path::to_path_buf))
+}