Support multiple packages in one repository.

README.md

@@ -27,12 +27,17 @@ A simple package manager for the Motoko programming language.
 ## How it works
 
 `vessel` is inspired by the [spago](https://github.com/purescript/spago) package
-manager for PureScript. Any git repository with a `src/` directory is a valid
+manager for PureScript.
+
+Any git repository with a `src/` directory is a valid
 package to `vessel`, which is a flexible and lightweight approach to package
 management, that is easily extended with more guarantees and features as our
 community grows. The two concepts you need to understand to work with `vessel`
 are _package sets_ and the _manifest_ file.
 
+If your git repository uses a source directory other than `src/`, you can still use `vessel`
+by specifying that source `path` explicitly.
+
 ### Package sets
 
 `vessel` uses the idea of a _package set_ to manage where it pulls dependencies
@@ -82,6 +87,7 @@ your `additions` in the `package-set.dhall` file:
 let additions = [
  { name = "mypackage"
  , repo = "file:///home/path/to/mypackage"
+ , path = None Text
  , version = "v1.0.0"
  , dependencies = ["base"]
  }
@@ -90,6 +96,40 @@ let additions = [
 
 Now you can depend on this package by adding `mypackage` to your `vessel.dhall` file.
 
+
+### What about *custom source paths* in a repo?
+
+Suppose that `https://github.com/theUsername/theRepo` uses a path other than `src/` for its Motoko source code.
+
+Assuming that the source path is `foo/bar`, we can specify that path using `path = Some "foo/bar"` for the package entry.
+
+### What about *multiple packages* in one `repo`?
+
+The `path` field also permits multiple packages within one repository.
+
+Suppose that `https://github.com/theUsername/theRepo` has two subdirectories, `apple` and `banana`, each with the source code for a `vessel` package.
+
+We can specify these packages in our package set as follows:
+
+```dhall
+{
+ "name": "apple",
+ "repo": "https://github.com/theUsername/theRepo.git",
+ "path": Some "apple/src",
+ "version": "v1.1.1",
+ "dependencies": ["base", "banana"]
+},
+{
+ "name": "banana",
+ "repo": "https://github.com/theUsername/theRepo.git",
+ "path": Some "banana/src",
+ "version": "v2.2.2",
+ "dependencies": ["base"]
+}
+```
+
+Notice that the field `path` appears in each entry, to direct `vessel` within the single, shared `repo`.
+
 ### How do I integrate `vessel` into my custom build?
 
 Running `vessel sources` will return flags in a format you can pass directly to

src/lib.rs

@@ -260,7 +260,8 @@ pub fn download_compiler(version: &str) -> Result<PathBuf> {
  Ok(dest)
 }
 
-/// Downloads a package either as a tar-ball from Github or clones it as a repo
+/// Downloads a package either as a tar-ball from Github or clones it as a repo.
+/// Returns its installation location.
 pub fn download_package(package: &Package) -> Result<PathBuf> {
  let package_dir = Path::new(".vessel").join(package.name.clone());
  if !package_dir.exists() {
@@ -294,7 +295,15 @@ pub fn download_package(package: &Package) -> Result<PathBuf> {
  package.name, package.version
  )
  }
- Ok(repo_dir.join("src"))
+ // include the package path within the repo, if it exists.
+ match package.path {
+ None => Ok(repo_dir.join("src")),
+ Some(ref p) => {
+ let q = Path::new(p);
+ assert!(q.is_relative()); // otherwise .join will misbehave
+ Ok(repo_dir.join(q))
+ }
+ }
 }
 
 /// Downloads and unpacks a tar-ball from Github into the `dest` path
@@ -370,7 +379,6 @@ fn clone_package(tmp: &Path, dest: &Path, repo: &str, version: &str) -> Result<(
  std::str::from_utf8(&checkout_result.stderr).unwrap()
  ));
  }
-
  fs::rename(repo_dir, dest)?;
  Ok(())
 }
@@ -505,20 +513,31 @@ pub type Tag = String;
 
 pub type Name = String;
 
+pub type PackagePath = String;
+
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, serde_dhall::StaticType)]
 pub struct Package {
  pub name: Name,
  pub repo: Url,
+ pub path: Option<PackagePath>,
  pub version: Tag,
  pub dependencies: Vec<Name>,
 }
 
 impl Package {
  pub fn install_path(&self) -> PathBuf {
- Path::new(".vessel")
+ let path = Path::new(".vessel")
  .join(self.name.clone())
- .join(self.version.clone())
- .join("src")
+ .join(self.version.clone());
+ // include the package path within the repo, if it exists.
+ match self.path {
+ None => path.join("src"),
+ Some(ref p) => {
+ let q = Path::new(p);
+ assert!(q.is_relative()); // otherwise .join will misbehave
+ path.join(q)
+ }
+ }
  }
 
  /// Returns all Motoko sources found inside this package's installation directory
@@ -609,6 +628,7 @@ mod test {
  Package {
  name: name.to_string(),
  repo: "".to_string(),
+ path: None,
  version: "".to_string(),
  dependencies: deps.into_iter().map(|x| x.to_string()).collect(),
  }