[clone] first steps towards launching git-upload-pack while…

…reusing as much code as possible.
Some refactoring required.

README.md

@@ -127,7 +127,7 @@ Please see _'Development Status'_ for a listing of all crates and their capabili
 
 ### git-transport
   * [ ] general purpose `connect(…)` for clients
-    * [ ] _file://_ and launching service application
+    * [ ] _file://_ launches service application
     * [ ] _ssh://_ launches service application in a remote shell using _ssh_
     * [ ] _git://_ establishes a tcp connection to a git daemon
     * [x] _http(s)://_ establishes connections to web server
@@ -143,7 +143,7 @@ Please see _'Development Status'_ for a listing of all crates and their capabili
       * [x] send values + receive data with sidebands
     * [x] V2 handshake
       * [x] send command request, receive response with sideband support
-    * [ ] ~~dumb~~ - _we opt out using this protocol seems too slow to be useful, unless it downloads entire packs for clones?_
+    * [ ] ~~'dumb'~~ - _we opt out using this protocol seems too slow to be useful, unless it downloads entire packs for clones?_
   * [x] authentication failures are communicated by io::ErrorKind::PermissionDenied, allowing other layers to retry
   * [ ] API documentation with examples
 

git-transport/src/client/file.rs

@@ -1,6 +1,13 @@
-use crate::client::git;
+use crate::{
+    client::{self, git, MessageKind, RequestWriter, SetServiceResponse, WriteMode},
+    Service,
+};
 use quick_error::quick_error;
-use std::{path::Path, process};
+use std::process::Stdio;
+use std::{
+    path::{Path, PathBuf},
+    process,
+};
 
 quick_error! {
     #[derive(Debug)]
@@ -11,9 +18,57 @@ quick_error! {
     }
 }
 
-pub fn connect(
-    _path: &Path,
-    _version: crate::Protocol,
-) -> Result<git::Connection<process::ChildStdout, process::ChildStdin>, Error> {
-    unimplemented!("file connection")
+// from https://github.com/git/git/blob/20de7e7e4f4e9ae52e6cc7cfaa6469f186ddb0fa/environment.c#L115:L115
+const ENV_VARS_TO_REMOVE: &'static [&'static str] = &[
+    "GIT_ALTERNATE_OBJECT_DIRECTORIES",
+    "GIT_CONFIG",
+    "GIT_CONFIG_PARAMETERS",
+    "GIT_OBJECT_DIRECTORY",
+    "GIT_DIR",
+    "GIT_WORK_TREE",
+    "GIT_IMPLICIT_WORK_TREE",
+    "GIT_GRAFT_FILE",
+    "GIT_INDEX_FILE",
+    "GIT_NO_REPLACE_OBJECTS",
+    "GIT_REPLACE_REF_BASE",
+    "GIT_PREFIX",
+    "GIT_INTERNAL_SUPER_PREFIX",
+    "GIT_SHALLOW_FILE",
+    "GIT_COMMON_DIR",
+];
+
+pub struct SpawnProcessOnDemand {
+    path: PathBuf,
+    version: crate::Protocol,
+    connection: Option<git::Connection<process::ChildStdout, process::ChildStdin>>,
+}
+
+impl client::Transport for SpawnProcessOnDemand {
+    fn handshake(&mut self, service: Service) -> Result<SetServiceResponse, client::Error> {
+        assert!(
+            self.connection.is_none(),
+            "cannot handshake twice with the same connection"
+        );
+        let mut cmd = std::process::Command::new(service.as_str());
+        for env_to_remove in ENV_VARS_TO_REMOVE {
+            cmd.env_remove(env_to_remove);
+        }
+        cmd.stderr(Stdio::null()).stdout(Stdio::piped()).stdin(Stdio::piped());
+        cmd.arg("--strict").arg("--timeout=0");
+        let child = cmd.spawn()?;
+        // self.connection = Some(git::Connection {})
+        unimplemented!("invoke command")
+    }
+
+    fn request(&mut self, write_mode: WriteMode, on_drop: Vec<MessageKind>) -> Result<RequestWriter, client::Error> {
+        unimplemented!()
+    }
+}
+
+pub fn connect(path: &Path, version: crate::Protocol) -> Result<SpawnProcessOnDemand, std::convert::Infallible> {
+    Ok(SpawnProcessOnDemand {
+        path: path.to_owned(),
+        version,
+        connection: None,
+    })
 }

git-url/tests/parse/file.rs

@@ -46,6 +46,10 @@ fn relative_file_path_without_protocol() -> crate::Result {
     assert_url(
         "../../path/to/git",
         url(Protocol::File, None, None, None, b"../../path/to/git", None),
+    )?;
+    assert_url(
+        "path/to/git",
+        url(Protocol::File, None, None, None, b"path/to/git", None),
     )
 }
 

tasks.md

@@ -46,6 +46,12 @@
 * **gixp-pack-receive**
   * [ ] hookup `git-protocol` with delegate to allow for receiving full packs
   * [ ] **gixp-pack-receive** may optionally write received refs to the specified directory
+  * [ ] journey tests for each connection method
+    * [ ] file
+    * [ ] git
+    * [ ] ssh
+    * [ ] https (unauthenticated)
+    * [ ] https (authenticated)
 
 ### NEXT ITERATION: Fetching _(more analysis needed after previous block)_