feat(libscoop|sync): basic support of uninstalling packages

What the `basic support` means is with this commit only packages
without using PowerShell scripts (`pre_uninstall`, `uninstaller`
and `post_uninstall`) are supported.

Signed-off-by: Chawye Hsu <[email protected]>

crates/libscoop/Cargo.toml

@@ -18,6 +18,7 @@ dirs = "5.0.1"
 flume = "0.10"
 futures = { version = "0.3", features = ["thread-pool"] }
 git2 = "0.17.2"
+junction = "1.0.0"
 log = "0.4"
 once_cell = "1.18.0"
 rayon = "1.7.0"

crates/libscoop/src/env.rs

@@ -0,0 +1,60 @@
+use crate::{error::Fallible, internal, package::Package, Event, Session};
+
+/// Unset all environment variables defined by a given package.
+pub fn remove(session: &Session, package: &Package) -> Fallible<()> {
+    assert!(package.is_installed());
+
+    // Unset environment variables
+    if let Some(env_set) = package.manifest().env_set() {
+        if let Some(tx) = session.emitter() {
+            let _ = tx.send(Event::PackageEnvVarRemoveStart);
+        }
+
+        let keys = env_set.keys();
+        for key in keys {
+            internal::env::set(key, "")?;
+        }
+
+        if let Some(tx) = session.emitter() {
+            let _ = tx.send(Event::PackageEnvVarRemoveDone);
+        }
+    }
+
+    // Remove environment path
+    if let Some(env_add_path) = package.manifest().env_add_path() {
+        let mut env_path_list = internal::env::get_env_path_list()?;
+        let config = session.config();
+        let mut app_path = config.root_path().join("apps");
+        app_path.push(package.name());
+
+        if let Some(tx) = session.emitter() {
+            let _ = tx.send(Event::PackageEnvPathRemoveStart);
+        }
+
+        let version = if config.no_junction() {
+            package.installed_version().unwrap()
+        } else {
+            "current"
+        };
+
+        let paths = env_add_path
+            .into_iter()
+            .map(|p| {
+                internal::path::normalize_path(app_path.join(version).join(p))
+                    .to_str()
+                    .unwrap()
+                    .to_owned()
+            })
+            .collect::<Vec<_>>();
+
+        env_path_list.retain(|p| !paths.contains(p));
+
+        internal::env::set("PATH", &env_path_list.join(";"))?;
+
+        if let Some(tx) = session.emitter() {
+            let _ = tx.send(Event::PackageEnvPathRemoveDone);
+        }
+    }
+
+    Ok(())
+}

crates/libscoop/src/event.rs

@@ -69,43 +69,88 @@ pub enum Event {
     /// Bucket update has made some progress.
     BucketUpdateProgress(BucketUpdateProgressContext),
 
-    /// Bucket update is finished.
+    /// Bucket update has finished.
     BucketUpdateDone,
 
-    /// Package resolving is started.
-    PackageResolveStart,
+    /// Package has started to be committed.
+    PackageCommitStart(String),
 
-    /// Package resolving is finished.
-    PackageResolveDone,
+    /// Package has been committed.
+    PackageCommitDone(String),
 
-    /// Calculating download size is started.
+    /// Calculating download size has started.
     PackageDownloadSizingStart,
 
-    /// Calculating download size is finished.
+    /// Calculating download size has finished.
     PackageDownloadSizingDone,
 
-    /// Package download is started.
+    /// Package download has started.
     PackageDownloadStart,
 
     /// Package download has made some progress.
     PackageDownloadProgress(PackageDownloadProgressContext),
 
-    /// Package download is finished.
+    /// Package download has finished.
     PackageDownloadDone,
 
-    /// Package integrity check is started.
+    /// Package environment path(s) removal has started.
+    PackageEnvPathRemoveStart,
+
+    /// Package environment path(s) removal has finished.
+    PackageEnvPathRemoveDone,
+
+    /// Package environment variable(s) removal has started.
+    PackageEnvVarRemoveStart,
+
+    /// Package environment variable(s) removal has finished.
+    PackageEnvVarRemoveDone,
+
+    /// Package integrity check has started.
     PackageIntegrityCheckStart,
 
     /// Package integrity check has made some progress.
     PackageIntegrityCheckProgress(String),
 
-    /// Package integrity check is finished.
+    /// Package integrity check has finished.
     PackageIntegrityCheckDone,
 
-    /// Package is started to be committed.
-    PackageCommitStart(String),
+    /// Package persist removal has started.
+    PackagePersistPurgeStart,
+
+    /// Package persist removal has finished.
+    PackagePersistPurgeDone,
+
+    /// Package PowerShell module removal has started.
+    PackagePsModuleRemoveStart(String),
+
+    /// Package PowerShell module removal has finished.
+    PackagePsModuleRemoveDone,
+
+    /// Package resolving has started.
+    PackageResolveStart,
+
+    /// Package resolving has finished.
+    PackageResolveDone,
+
+    /// Package shim removal has started.
+    PackageShimRemoveStart,
+
+    /// Package shim removal has made some progress.
+    PackageShimRemoveProgress(String),
+
+    /// Package shim removal has finished.
+    PackageShimRemoveDone,
+
+    /// Package shortcut removal has started.
+    PackageShortcutRemoveStart,
+
+    /// Package shortcut removal has made some progress.
+    PackageShortcutRemoveProgress(String),
+
+    /// Package shortcut removal has finished.
+    PackageShortcutRemoveDone,
 
-    /// Package sync operation is finished.
+    /// Package sync operation has finished.
     PackageSyncDone,
 
     /// Prompt the user to confirm the transaction.

crates/libscoop/src/internal/env.rs

@@ -24,9 +24,21 @@ pub fn set(key: &str, value: &str) -> Fallible<()> {
     let (env, _) = HKCU.create_subkey(path)?;
 
     if value.is_empty() {
-        env.delete_value(key)?;
+        // ignore error of deleting non-existent value
+        let _ = env.delete_value(key);
     } else {
         env.set_value(key, &value)?;
     }
     Ok(())
 }
+
+/// Get the value of the `PATH` environment variable as a list of paths.
+pub fn get_env_path_list() -> Fallible<Vec<String>> {
+    let env_path = get("PATH")?;
+    Ok(env_path
+        .into_string()
+        .unwrap()
+        .split(';')
+        .map(|s| s.to_owned())
+        .collect())
+}

crates/libscoop/src/internal/fs.rs

@@ -17,8 +17,9 @@ pub fn ensure_dir<P: AsRef<Path> + ?Sized>(path: &P) -> io::Result<()> {
     std::fs::create_dir_all(path.as_ref())
 }
 
-pub fn remove_dir<P: AsRef<Path> + ?Sized>(path: &P) -> io::Result<()> {
-    remove_dir_all::remove_dir_all(path.as_ref())
+/// Remove given `path` recursively.
+pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
+    remove_dir_all::remove_dir_all(path)
 }
 
 /// Remove all files and subdirectories in given `path`.
@@ -83,3 +84,52 @@ where
         .open(path)?;
     Ok(serde_json::to_writer_pretty(file, &data)?)
 }
+
+/// Remove a symlink at `lnk`.
+pub fn remove_symlink<P: AsRef<Path>>(lnk: P) -> io::Result<()> {
+    let lnk = lnk.as_ref();
+    let metadata = lnk.symlink_metadata()?;
+    let mut permissions = metadata.permissions();
+
+    // Remove possible readonly flag on the symlink added by `attrib +R` command
+    if permissions.readonly() {
+        // Remove readonly flag
+        permissions.set_readonly(false);
+        std::fs::set_permissions(lnk, permissions)?;
+    }
+
+    // We knew that `lnk` is a symlink but we don't know if it is a file or a
+    // directory. So we need to check its metadata to determine how to remove
+    // it. The file type of the symlink itself is always `FileType::Symlink`
+    // and `symlink_metadata::is_dir` always returns `false` for symlinks, so
+    // we have to check the metadata of the target file.
+    let target_metadata = lnk.metadata()?;
+
+    if target_metadata.is_dir() {
+        std::fs::remove_dir(lnk)
+    } else {
+        std::fs::remove_file(lnk)
+    }
+}
+
+/// Create a directory symlink at `lnk` pointing to `src`.
+pub fn symlink_dir<P: AsRef<Path>, Q: AsRef<Path>>(src: P, lnk: Q) -> io::Result<()> {
+    // It is possible to create a symlink on Windows, but one of the following
+    // conditions must be met:
+    //
+    // Either: the process has the `SeCreateSymbolicLinkPrivilege` privilege,
+    // or: the OS is Windows 10 Creators Update or later and Developer Mode
+    // enabled.
+    //
+    // We prefer symlink over junction because:
+    // https://stackoverflow.com/questions/9042542/what-is-the-difference-between-ntfs-junction-points-and-symbolic-links
+    //
+    // Here we try to create a symlink first, and if it fails, we try to create
+    // a junction which does not require any special privilege and works on
+    // older versions of Windows.
+    if std::os::windows::fs::symlink_dir(src.as_ref(), lnk.as_ref()).is_err() {
+        junction::create(src, lnk)
+    } else {
+        Ok(())
+    }
+}

crates/libscoop/src/lib.rs

@@ -37,11 +37,16 @@ mod bucket;
 mod cache;
 mod config;
 mod constant;
+mod env;
 mod error;
 mod event;
 mod internal;
 mod package;
+mod persist;
+mod psmodule;
 mod session;
+mod shim;
+mod shortcut;
 
 pub mod operation;