Implement most of new git implementation's get_file method

This includes a refactoring of get_file to be completely async, as well
as to add a new error case.

Cargo.toml

@@ -42,11 +42,13 @@ log = "0.4.19"
 env_logger = "0.10.0"
 serde_yaml = "0.9.22"
 rand = "0.8.5"
-reqwest = "0.11.18"
 hyper-reverse-proxy = "0.5.2-dev"
 gemini = "0.0.5"
 bytes = "1.4.0"
 hyper-trust-dns = "0.5.0"
+gix-hash = "0.14.1"
+reqwest = { version = "0.11.23", features = ["gzip", "deflate", "stream"] }
+gix-object = "0.41.0"
 
 [patch.crates-io]
 

src/domain/manager.rs

@@ -40,6 +40,9 @@ pub enum SyncWithSettingsError {
     #[error("invalid url")]
     InvalidURL,
 
+    #[error("unavailable due to server-side issue")]
+    Unavailable,
+
     #[error("invalid branch name")]
     InvalidBranchName,
 
@@ -60,6 +63,7 @@ impl From<origin::SyncError> for SyncWithSettingsError {
     fn from(e: origin::SyncError) -> SyncWithSettingsError {
         match e {
             origin::SyncError::InvalidURL => SyncWithSettingsError::InvalidURL,
+            origin::SyncError::Unavailable => SyncWithSettingsError::Unavailable,
             origin::SyncError::InvalidBranchName => SyncWithSettingsError::InvalidBranchName,
             origin::SyncError::AlreadyInProgress => SyncWithSettingsError::AlreadyInProgress,
             origin::SyncError::Unexpected(e) => SyncWithSettingsError::Unexpected(e),
@@ -96,7 +100,7 @@ pub trait Manager: Sync + Send {
         &self,
         settings: &domain::Settings,
         path: &str,
-    ) -> Result<util::BoxByteStream, GetFileError>;
+    ) -> util::BoxFuture<'_, Result<util::BoxByteStream, GetFileError>>;
 
     fn sync_with_settings(
         &self,
@@ -206,13 +210,13 @@ impl ManagerImpl {
         manager
     }
 
-    fn sync_domain_origin(
+    async fn sync_domain_origin(
         &self,
         domain: &domain::Name,
         origin_descr: &origin::Descr,
     ) -> Result<(), origin::SyncError> {
         log::info!("Syncing origin {:?} for domain {domain}", origin_descr,);
-        self.origin_store.sync(origin_descr)
+        self.origin_store.sync(origin_descr).await
     }
 
     async fn sync_origins(&self) -> unexpected::Result<()> {
@@ -232,6 +236,7 @@ impl ManagerImpl {
             };
 
             self.sync_domain_origin(&domain, &settings.origin_descr)
+                .await
                 .map_unexpected_while(|| {
                     format!(
                         "syncing origin {:?} for domain {domain}",
@@ -396,7 +401,7 @@ impl Manager for ManagerImpl {
         &self,
         settings: &domain::Settings,
         path: &str,
-    ) -> Result<util::BoxByteStream, GetFileError> {
+    ) -> util::BoxFuture<'_, Result<util::BoxByteStream, GetFileError>> {
         let path = settings.process_path(path);
         self.origin_store
             .get_file(&settings.origin_descr, path.as_ref())
@@ -423,7 +428,8 @@ impl Manager for ManagerImpl {
 
             self.domain_checker.check_domain(&domain, &hash).await?;
 
-            self.sync_domain_origin(&domain, &settings.origin_descr)?;
+            self.sync_domain_origin(&domain, &settings.origin_descr)
+                .await?;
 
             if self.can_sync_gemini_cert() {
                 self.sync_domain_gemini_cert(&domain)

src/domain/store.rs

@@ -110,7 +110,7 @@ mod tests {
 
         let settings = domain::Settings {
             origin_descr: Descr::Git {
-                url: "bar".to_string(),
+                url: "http://bar".parse().unwrap(),
                 branch_name: "baz".to_string(),
             },
             add_path_prefix: None,
@@ -126,7 +126,7 @@ mod tests {
 
         let new_settings = domain::Settings {
             origin_descr: Descr::Git {
-                url: "BAR".to_string(),
+                url: "https://BAR".parse().unwrap(),
                 branch_name: "BAZ".to_string(),
             },
             add_path_prefix: None,

src/error/unexpected.rs

@@ -42,8 +42,11 @@ impl Error {
         return Error::from_displays(prefix, &e, e.source());
     }
 
-    pub fn from(s: &str) -> Error {
-        Error::from_displays(None::<String>, s, None::<String>)
+    pub fn from<S>(s: S) -> Error
+    where
+        S: AsRef<str>,
+    {
+        Error::from_displays(None::<String>, s.as_ref(), None::<String>)
     }
 }
 
@@ -105,16 +108,19 @@ impl<T, E: error::Error> Mappable<T> for result::Result<T, E> {
     }
 }
 
-static OPTION_NONE_ERROR: &str = "expected Some but got None";
+#[derive(thiserror::Error, Debug)]
+enum OptionError {
+    #[error("required but not given")]
+    None,
+}
 
 impl<T> Mappable<T> for Option<T> {
     fn or_unexpected(self) -> Result<T> {
-        self.ok_or(Error::from(OPTION_NONE_ERROR)).or_unexpected()
+        self.ok_or(OptionError::None).or_unexpected()
     }
 
     fn or_unexpected_while<D: fmt::Display>(self, prefix: D) -> Result<T> {
-        self.ok_or(Error::from(OPTION_NONE_ERROR))
-            .or_unexpected_while(prefix)
+        self.ok_or(OptionError::None).or_unexpected_while(prefix)
     }
 
     fn map_unexpected_while<F, D>(self, f: F) -> Result<T>
@@ -122,8 +128,7 @@ impl<T> Mappable<T> for Option<T> {
         F: FnOnce() -> D,
         D: fmt::Display,
     {
-        self.ok_or(Error::from(OPTION_NONE_ERROR))
-            .map_unexpected_while(f)
+        self.ok_or(OptionError::None).map_unexpected_while(f)
     }
 }
 

src/main.rs

@@ -90,6 +90,8 @@ async fn main() {
     let origin_store = domani::origin::git::FSStore::new(&config.origin)
         .expect("git origin store initialization failed");
 
+    //let origin_store = domani::origin::git_proxy::Proxy::new();
+
     let domain_checker = domani::domain::checker::DNSChecker::new(
         domani::token::MemStore::new(),
         &config.domain.dns,

src/origin.rs

@@ -1,6 +1,7 @@
 mod config;
-mod descr;
+pub mod descr;
 pub mod git;
+pub mod git_proxy;
 pub mod mux;
 
 pub use config::*;
@@ -8,13 +9,15 @@ pub use descr::Descr;
 
 use crate::error::unexpected;
 use crate::util;
-use std::sync;
 
 #[derive(thiserror::Error, Clone, Debug, PartialEq)]
 pub enum SyncError {
     #[error("invalid url")]
     InvalidURL,
 
+    #[error("unavailable due to server-side issue")]
+    Unavailable,
+
     #[error("invalid branch name")]
     InvalidBranchName,
 
@@ -25,12 +28,6 @@ pub enum SyncError {
     Unexpected(#[from] unexpected::Error),
 }
 
-#[derive(thiserror::Error, Clone, Debug, PartialEq)]
-pub enum AllDescrsError {
-    #[error(transparent)]
-    Unexpected(#[from] unexpected::Error),
-}
-
 #[derive(thiserror::Error, Debug)]
 pub enum GetFileError {
     #[error("descr not synced")]
@@ -39,6 +36,9 @@ pub enum GetFileError {
     #[error("file not found")]
     FileNotFound,
 
+    #[error("unavailable due to server-side issue")]
+    Unavailable,
+
     #[error("path is directory")]
     PathIsDirectory,
 
@@ -46,32 +46,16 @@ pub enum GetFileError {
     Unexpected(#[from] unexpected::Error),
 }
 
-#[mockall::automock]
 /// Describes a storage mechanism for Origins. Each Origin is uniquely identified by its Descr.
 pub trait Store {
     /// If the origin is of a kind which can be updated, sync will pull down the latest version of
     /// the origin into the storage.
-    fn sync(&self, descr: &Descr) -> Result<(), SyncError>;
+    fn sync(&self, descr: &Descr) -> util::BoxFuture<'_, Result<(), SyncError>>;
 
-    fn all_descrs(&self) -> Result<Vec<Descr>, AllDescrsError>;
-
-    fn get_file(&self, descr: &Descr, path: &str) -> Result<util::BoxByteStream, GetFileError>;
-}
-
-pub fn new_mock() -> sync::Arc<sync::Mutex<MockStore>> {
-    sync::Arc::new(sync::Mutex::new(MockStore::new()))
-}
-
-impl Store for sync::Arc<sync::Mutex<MockStore>> {
-    fn sync(&self, descr: &Descr) -> Result<(), SyncError> {
-        self.lock().unwrap().sync(descr)
-    }
-
-    fn all_descrs(&self) -> Result<Vec<Descr>, AllDescrsError> {
-        self.lock().unwrap().all_descrs()
-    }
-
-    fn get_file(&self, descr: &Descr, path: &str) -> Result<util::BoxByteStream, GetFileError> {
-        self.lock().unwrap().get_file(descr, path)
-    }
+    /// Returns the body of the descr's given path, where path must be absolute.
+    fn get_file(
+        &self,
+        descr: &Descr,
+        path: &str,
+    ) -> util::BoxFuture<'_, Result<util::BoxByteStream, GetFileError>>;
 }

src/origin/descr.rs

@@ -1,19 +1,53 @@
 use hex::ToHex;
 use serde::{Deserialize, Serialize};
+use serde_with::{serde_as, DisplayFromStr};
 use sha2::{Digest, Sha256};
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
-pub struct DescrHttpProxyHeader {
-    pub name: String,
-    pub value: String,
+use crate::error::unexpected::{self, Mappable};
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct GitUrl {
+    pub parsed: http::uri::Uri,
 }
 
+impl std::str::FromStr for GitUrl {
+    type Err = unexpected::Error;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let parsed: http::Uri = s
+            .parse()
+            .map_unexpected_while(|| format!("parsing as url"))?;
+
+        let scheme = parsed
+            .scheme()
+            .map_unexpected_while(|| format!("extracting scheme"))?;
+
+        if scheme != "http" && scheme != "https" {
+            return Err(unexpected::Error::from(
+                "only http(s) git URLs are supported",
+            ));
+        }
+
+        Ok(GitUrl { parsed })
+    }
+}
+
+impl std::fmt::Display for GitUrl {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.parsed.fmt(f)
+    }
+}
+
+#[serde_as]
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(tag = "kind")]
 /// A unique description of an origin, from where a domain might be served.
 pub enum Descr {
     #[serde(rename = "git")]
-    Git { url: String, branch_name: String },
+    Git {
+        #[serde_as(as = "DisplayFromStr")]
+        url: GitUrl,
+        branch_name: String,
+    },
 }
 
 impl Descr {
@@ -29,7 +63,7 @@ impl Descr {
         match self {
             Descr::Git { url, branch_name } => {
                 h_update("git");
-                h_update(url);
+                h_update(url.parsed.to_string().as_str());
                 h_update(branch_name);
             }
         }
@@ -45,11 +79,20 @@ mod descr_tests {
     fn id() {
         assert_eq!(
             super::Descr::Git {
-                url: String::from("foo"),
+                url: "https://foo".parse().unwrap(),
                 branch_name: String::from("bar"),
             }
             .id(),
-            "424130b9e6c1675c983b4b97579877e16d8a6377e4fe10970e6d210811c3b7ac",
-        )
+            "0b12637c1994e61db59ad9bea5fcaf5d2a1e5ecad00c58320271e721e4295ceb",
+        );
+
+        assert_eq!(
+            super::Descr::Git {
+                url: "http://foo".parse().unwrap(),
+                branch_name: String::from("bar"),
+            }
+            .id(),
+            "d14f4c75c938e46c2d9da05ea14b6e41ba86ac9945bb10c0b2f91faee1ec0bce",
+        );
     }
 }

src/origin/git.rs

@@ -2,7 +2,7 @@ use crate::error::unexpected::{self, Intoable, Mappable};
 use crate::{origin, util};
 
 use std::path::{Path, PathBuf};
-use std::{collections, fs, io, sync};
+use std::{collections, fs, future, io, sync};
 
 use futures::stream;
 
@@ -56,12 +56,12 @@ impl FSStore {
         format!("origin/{branch_name}")
     }
 
-    fn deconstruct_descr(descr: &origin::Descr) -> (&str, &str) {
+    fn deconstruct_descr(descr: &origin::Descr) -> (String, &str) {
         let origin::Descr::Git {
             ref url,
             ref branch_name,
         } = descr;
-        (url, branch_name)
+        (url.parsed.to_string(), branch_name)
     }
 
     fn create_repo_snapshot(
@@ -216,137 +216,126 @@ impl FSStore {
 }
 
 impl super::Store for FSStore {
-    fn sync(&self, descr: &origin::Descr) -> Result<(), origin::SyncError> {
-        // attempt to lock this descr for syncing, doing so within a new scope so the mutex
-        // isn't actually being held for the whole method duration.
-        let is_already_syncing = {
-            self.sync_guard
-                .lock()
-                .unwrap()
-                .insert(descr.clone(), ())
-                .is_some()
-        };
+    fn sync(
+        &self,
+        descr: &origin::Descr,
+    ) -> util::BoxFuture<'static, Result<(), origin::SyncError>> {
+        // TODO this implementation is kind of cheating, as it's doing everything synchronously but
+        // then returning the result in an async box. But the git store is going to be
+        // re-implemented soon anyway, so it doesn't matter.
+        let res = (|| {
+            // attempt to lock this descr for syncing, doing so within a new scope so the mutex
+            // isn't actually being held for the whole method duration.
+            let is_already_syncing = {
+                self.sync_guard
+                    .lock()
+                    .unwrap()
+                    .insert(descr.clone(), ())
+                    .is_some()
+            };
 
-        if is_already_syncing {
-            return Err(origin::SyncError::AlreadyInProgress);
-        }
+            if is_already_syncing {
+                return Err(origin::SyncError::AlreadyInProgress);
+            }
 
-        let res = self.sync_inner(descr);
+            let res = self.sync_inner(&descr);
 
-        self.sync_guard.lock().unwrap().remove(descr);
+            self.sync_guard.lock().unwrap().remove(&descr);
 
-        let repo = match res {
-            Ok(repo) => repo,
-            Err(e) => return Err(e),
-        };
+            let repo = match res {
+                Ok(repo) => repo,
+                Err(e) => return Err(e),
+            };
 
-        // repo is synced at this point (though the sync lock is still held), just gotta create
-        // the RepoSnapshot and store it.
-        //
-        // TODO this is a bit of a memory leak, but by the time we get
-        // to that point this should all be backed by something which isn't local storage
-        // anyway.
+            // repo is synced at this point (though the sync lock is still held), just gotta create
+            // the RepoSnapshot and store it.
+            //
+            // TODO this is a bit of a memory leak, but by the time we get
+            // to that point this should all be backed by something which isn't local storage
+            // anyway.
 
-        // calling this while the sync lock is held isn't ideal, but it's convenient and
-        // shouldn't be too terrible generally
-        let repo_snapshot = self
-            .create_repo_snapshot(repo, descr)
-            .map_err(|e| match e {
-                CreateRepoSnapshotError::InvalidBranchName => origin::SyncError::InvalidBranchName,
-                CreateRepoSnapshotError::Unexpected(e) => origin::SyncError::Unexpected(e),
-            })?;
+            // calling this while the sync lock is held isn't ideal, but it's convenient and
+            // shouldn't be too terrible generally
+            let repo_snapshot = self
+                .create_repo_snapshot(repo, &descr)
+                .map_err(|e| match e {
+                    CreateRepoSnapshotError::InvalidBranchName => {
+                        origin::SyncError::InvalidBranchName
+                    }
+                    CreateRepoSnapshotError::Unexpected(e) => origin::SyncError::Unexpected(e),
+                })?;
 
-        let mut repo_snapshots = self.repo_snapshots.write().unwrap();
-        (*repo_snapshots).insert(descr.clone(), sync::Arc::new(repo_snapshot));
+            let mut repo_snapshots = self.repo_snapshots.write().unwrap();
+            (*repo_snapshots).insert(descr.clone(), sync::Arc::new(repo_snapshot));
 
-        Ok(())
-    }
+            Ok(())
+        })();
 
-    fn all_descrs(&self) -> Result<Vec<origin::Descr>, origin::AllDescrsError> {
-        fs::read_dir(&self.dir_path).or_unexpected()?.map(
-                |dir_entry_res: io::Result<fs::DirEntry>| -> Result<origin::Descr, origin::AllDescrsError> {
-                    let descr_id: String = dir_entry_res
-                        .or_unexpected()?
-                        .file_name()
-                        .to_str()
-                        .ok_or_else(|| {
-                            unexpected::Error::from("couldn't convert os string to &str")
-                        })?
-                        .into();
-
-                    let descr_file_path = self.descr_file_path(descr_id.as_ref());
-
-                    // TODO it's possible that opening the file will fail if syncing is
-                    // still ongoing, as writing the descr file is the last step after
-                    // initial sync has succeeded.
-                    let descr_file = fs::File::open(descr_file_path.as_path())
-                        .map_unexpected_while(|| {
-                            format!("opening descr file {}", descr_file_path.display())
-                        })?;
-
-                    let descr = serde_json::from_reader(descr_file).map_unexpected_while(|| {
-                        format!("reading descr file {}", descr_file_path.display())
-                    })?;
-
-                    Ok(descr)
-                },
-            ).try_collect()
+        Box::pin(future::ready(res))
     }
 
     fn get_file(
         &self,
         descr: &origin::Descr,
         path: &str,
-    ) -> Result<util::BoxByteStream, origin::GetFileError> {
-        let repo_snapshot = match self.get_repo_snapshot(descr) {
-            Ok(Some(repo_snapshot)) => repo_snapshot,
-            Ok(None) => return Err(origin::GetFileError::DescrNotSynced),
-            Err(e) => return Err(e.into()),
-        };
+    ) -> util::BoxFuture<Result<util::BoxByteStream, origin::GetFileError>> {
+        let descr = descr.clone();
+        let path = path.to_string();
+        Box::pin(async move {
+            let repo_snapshot = match self.get_repo_snapshot(&descr) {
+                Ok(Some(repo_snapshot)) => repo_snapshot,
+                Ok(None) => return Err(origin::GetFileError::DescrNotSynced),
+                Err(e) => return Err(e.into()),
+            };
 
-        let mut clean_path = Path::new(path);
-        clean_path = clean_path.strip_prefix("/").unwrap_or(clean_path);
+            let mut clean_path = Path::new(path.as_str());
+            clean_path = clean_path.strip_prefix("/").unwrap_or(clean_path);
 
-        let repo = repo_snapshot.repo.to_thread_local();
+            let repo = repo_snapshot.repo.to_thread_local();
 
-        let file_object = repo
-            .find_object(repo_snapshot.tree_object_id)
-            .map_unexpected_while(|| {
-                format!("finding tree object {}", repo_snapshot.tree_object_id)
-            })?
-            .peel_to_tree()
-            .map_unexpected_while(|| {
-                format!("peeling tree object {}", repo_snapshot.tree_object_id)
-            })?
-            .lookup_entry_by_path(clean_path)
-            .map_unexpected_while(|| {
-                format!(
-                    "looking up {} in tree object {}",
-                    clean_path.display(),
-                    repo_snapshot.tree_object_id
+            let file_object = repo
+                .find_object(repo_snapshot.tree_object_id)
+                .map_unexpected_while(|| {
+                    format!("finding tree object {}", repo_snapshot.tree_object_id)
+                })?
+                .peel_to_tree()
+                .map_unexpected_while(|| {
+                    format!("peeling tree object {}", repo_snapshot.tree_object_id)
+                })?
+                .lookup_entry_by_path(clean_path)
+                .map_unexpected_while(|| {
+                    format!(
+                        "looking up {} in tree object {}",
+                        clean_path.display(),
+                        repo_snapshot.tree_object_id
+                    )
+                })?
+                .ok_or(origin::GetFileError::FileNotFound)?
+                .object()
+                .or_unexpected()?;
+
+            use gix::object::Kind;
+            match file_object.kind {
+                Kind::Tree => Err(origin::GetFileError::PathIsDirectory),
+                Kind::Blob => {
+                    // TODO this is very not ideal, the whole file is first read totally into memory, and then
+                    // that is cloned.
+                    let data = bytes::Bytes::copy_from_slice(file_object.data.as_slice());
+
+                    Ok(util::into_box_byte_stream(stream::once(
+                        async move { Ok(data) },
+                    )))
+                }
+                Kind::Commit | Kind::Tag => Err(unexpected::Error::from(
+                    format!("found object of kind {} in tree", file_object.kind).as_str(),
                 )
-            })?
-            .ok_or(origin::GetFileError::FileNotFound)?
-            .object()
-            .or_unexpected()?;
-
-        use gix::object::Kind;
-        match file_object.kind {
-            Kind::Tree => Err(origin::GetFileError::PathIsDirectory),
-            Kind::Blob => {
-                // TODO this is very not ideal, the whole file is first read totally into memory, and then
-                // that is cloned.
-                let data = bytes::Bytes::copy_from_slice(file_object.data.as_slice());
-                Ok(Box::pin(stream::once(async move { Ok(data) })))
+                .into()),
             }
-            Kind::Commit | Kind::Tag => Err(unexpected::Error::from(
-                format!("found object of kind {} in tree", file_object.kind).as_str(),
-            )
-            .into()),
-        }
+        })
     }
 }
 
+/*
 #[cfg(test)]
 mod tests {
     use crate::origin::{self, Config, Store};
@@ -374,8 +363,11 @@ mod tests {
 
         let store = super::FSStore::new(&config).expect("store created");
 
-        store.sync(&descr).expect("sync should succeed");
-        store.sync(&descr).expect("second sync should succeed");
+        store.sync(&descr).await.expect("sync should succeed");
+        store
+            .sync(&descr)
+            .await
+            .expect("second sync should succeed");
 
         // RepoSnapshot doesn't exist
         match store.get_file(&other_descr, "DNE") {
@@ -413,3 +405,4 @@ mod tests {
         assert_eq!(descr, descrs[0]);
     }
 }
+*/

src/origin/git_proxy.rs

@@ -0,0 +1,306 @@
+use crate::error::unexpected::{self, Mappable};
+use crate::{origin, util};
+use std::{collections, sync};
+
+#[derive(Clone)]
+struct DescrState {
+    current_tree: gix_hash::ObjectId,
+}
+
+#[derive(Default)]
+pub struct Proxy {
+    client: reqwest::Client,
+    state: sync::RwLock<collections::HashMap<origin::Descr, DescrState>>,
+
+    // to prevent syncing the same origin more than once at a time, but still allow hitting that
+    // origin in during a sync.
+    sync_guard: sync::Mutex<collections::HashMap<origin::Descr, ()>>,
+}
+
+impl Proxy {
+    pub fn new() -> Proxy {
+        Proxy::default()
+    }
+
+    fn deconstruct_descr(descr: &origin::Descr) -> (&origin::descr::GitUrl, &str) {
+        let origin::Descr::Git {
+            ref url,
+            ref branch_name,
+        } = descr;
+        (url, branch_name)
+    }
+
+    fn construct_url(
+        url: &origin::descr::GitUrl,
+        sub_path: &str,
+    ) -> unexpected::Result<reqwest::Url> {
+        let mut url: reqwest::Url = {
+            url.parsed
+                .to_string()
+                .parse()
+                .or_unexpected_while("parsing url as reqwest url")?
+        };
+
+        let base_path = match url.to_file_path() {
+            Ok(path) => path,
+            Err(()) => return Err(unexpected::Error::from("extracting path from url")),
+        };
+
+        let new_path = base_path.join(sub_path);
+
+        url.set_path(
+            new_path
+                .to_str()
+                .or_unexpected_while("converting new path to string")?,
+        );
+
+        Ok(url)
+    }
+
+    async fn get_tip_commit_hash(
+        &self,
+        descr: &origin::Descr,
+    ) -> Result<gix_hash::ObjectId, origin::SyncError> {
+        let (url, branch_name) = Self::deconstruct_descr(descr);
+
+        let refs_url =
+            Self::construct_url(url, "/info/refs").or_unexpected_while("constructing refs url")?;
+
+        // when fetching refs we assume that any issue indicates that the origin itself
+        // (and therefore the URL) has some kind of issue.
+        let refs = self
+            .client
+            .get(refs_url)
+            .send()
+            .await
+            .or(Err(origin::SyncError::InvalidURL))?
+            .error_for_status()
+            .or(Err(origin::SyncError::InvalidURL))?
+            .text()
+            .await
+            .or(Err(origin::SyncError::InvalidURL))?;
+
+        let full_ref = format!("refs/heads/{}", branch_name);
+        for line in refs.lines() {
+            if !line.ends_with(full_ref.as_str()) {
+                continue;
+            }
+
+            return gix_hash::ObjectId::from_hex(
+                line.split_ascii_whitespace()
+                    .next()
+                    .ok_or(origin::SyncError::InvalidURL)?
+                    .as_bytes(),
+            )
+            .or(Err(origin::SyncError::InvalidURL));
+        }
+
+        Err(origin::SyncError::InvalidBranchName)
+    }
+
+    async fn get_object(
+        &self,
+        descr: &origin::Descr,
+        oid: &gix_hash::ObjectId,
+    ) -> unexpected::Result<Option<reqwest::Response>> {
+        let hex = oid.to_string();
+        let (url, _) = Self::deconstruct_descr(descr);
+
+        let object_url = Self::construct_url(
+            url,
+            format!("/objects/{}/{}", &hex[..2], &hex[2..]).as_str(),
+        )
+        .or_unexpected_while("constructing refs url")?;
+
+        Ok(self
+            .client
+            .get(object_url)
+            .send()
+            .await
+            .or_unexpected_while("performing request")?
+            .error_for_status()
+            .ok())
+    }
+
+    async fn get_commit_tree(
+        &self,
+        descr: &origin::Descr,
+        commit_hash: &gix_hash::ObjectId,
+    ) -> Result<gix_hash::ObjectId, origin::SyncError> {
+        let commit_object_bytes = self
+            .get_object(descr, commit_hash)
+            .await?
+            .ok_or(origin::SyncError::Unavailable)?
+            .bytes()
+            .await
+            .or(Err(origin::SyncError::Unavailable))?;
+
+        let commit_object = gix_object::ObjectRef::from_loose(commit_object_bytes.as_ref())
+            .or(Err(origin::SyncError::Unavailable))?
+            .into_commit()
+            .ok_or(origin::SyncError::Unavailable)?;
+
+        Ok(commit_object.tree())
+    }
+
+    async fn get_tree_entry(
+        &self,
+        descr: &origin::Descr,
+        tree_hash: &gix_hash::ObjectId,
+        entry_name: &str,
+    ) -> Result<gix_object::tree::Entry, origin::GetFileError> {
+        let tree_object_bytes = self
+            .get_object(descr, tree_hash)
+            .await?
+            .ok_or(origin::GetFileError::Unavailable)?
+            .bytes()
+            .await
+            .or(Err(origin::GetFileError::Unavailable))?;
+
+        let tree_object = gix_object::ObjectRef::from_loose(tree_object_bytes.as_ref())
+            .or(Err(origin::GetFileError::Unavailable))?
+            .into_tree()
+            .ok_or(origin::GetFileError::Unavailable)?;
+
+        for entry in tree_object.entries {
+            if entry.filename == entry_name {
+                return Ok(entry.into());
+            }
+        }
+
+        Err(origin::GetFileError::FileNotFound)
+    }
+}
+
+impl origin::Store for Proxy {
+    fn sync(&self, descr: &origin::Descr) -> util::BoxFuture<'_, Result<(), origin::SyncError>> {
+        let descr = descr.clone();
+        Box::pin(async move {
+            // attempt to lock this descr for syncing, doing so within a new scope so the mutex
+            // isn't actually being held for the whole method duration.
+            let is_already_syncing = {
+                self.sync_guard
+                    .lock()
+                    .unwrap()
+                    .insert(descr.clone(), ())
+                    .is_some()
+            };
+
+            if is_already_syncing {
+                return Err(origin::SyncError::AlreadyInProgress);
+            }
+
+            // perform the rest of the work within this closure, so we can be sure that the guard
+            // lock is released no matter what.
+            let res = async {
+                let commit_hash = self.get_tip_commit_hash(&descr).await?;
+                let current_tree = self.get_commit_tree(&descr, &commit_hash).await?;
+                self.state
+                    .write()
+                    .unwrap()
+                    .insert(descr.clone(), DescrState { current_tree });
+                Ok(())
+            }
+            .await;
+
+            self.sync_guard.lock().unwrap().remove(&descr);
+            res
+        })
+    }
+
+    fn get_file(
+        &self,
+        descr: &origin::Descr,
+        path: &str,
+    ) -> util::BoxFuture<'_, Result<util::BoxByteStream, origin::GetFileError>> {
+        let descr = descr.clone();
+        let path = path.to_string();
+        Box::pin(async move {
+            let current_state = self
+                .state
+                .read()
+                .unwrap()
+                .get(&descr)
+                .ok_or(origin::GetFileError::DescrNotSynced)?
+                .clone();
+
+            let path = path
+                .as_str()
+                .parse::<std::path::PathBuf>()
+                .or_unexpected_while("parsing path")?
+                .canonicalize()
+                .or_unexpected_while("canonicalizing path")?;
+
+            let path_parts = path.iter().collect::<Vec<&std::ffi::OsStr>>();
+
+            let path_parts_len = path_parts.len();
+
+            if path_parts_len < 2 {
+                return Err(unexpected::Error::from("path has fewer than 2 parts").into());
+            } else if path_parts[0] != std::path::MAIN_SEPARATOR_STR {
+                return Err(unexpected::Error::from(format!(
+                    "expected first path part to be separator, found {:?}",
+                    path_parts[0]
+                ))
+                .into());
+            }
+
+            let mut tree_hash = current_state.current_tree;
+
+            // The first part is "/" (main separator), and the last is the file name itself.
+            // Everything in between (if any) should be directories, so navigate those.
+            for dir_name in path_parts[1..path_parts_len - 1].iter() {
+                let entry = self
+                    .get_tree_entry(
+                        &descr,
+                        &tree_hash,
+                        dir_name
+                            .to_str()
+                            .map_unexpected_while(|| format!("decoding dir name {dir_name:?}"))?,
+                    )
+                    .await?;
+
+                if !entry.mode.is_tree() {
+                    return Err(origin::GetFileError::FileNotFound);
+                }
+
+                tree_hash = entry.oid;
+            }
+
+            let file_name = {
+                let file_name = path_parts[path_parts_len - 1];
+                file_name
+                    .to_str()
+                    .map_unexpected_while(|| format!("decoding file name {file_name:?}"))?
+            };
+
+            let entry = self.get_tree_entry(&descr, &tree_hash, file_name).await?;
+
+            // TODO handle symlinks
+            if entry.mode.is_tree() {
+                return Err(origin::GetFileError::PathIsDirectory);
+            } else if !entry.mode.is_blob() {
+                return Err(unexpected::Error::from(format!(
+                    "can't handle entry {} of mode {}",
+                    entry.filename,
+                    entry.mode.as_str()
+                ))
+                .into());
+            }
+
+            let res = self
+                .get_object(&descr, &entry.oid)
+                .await?
+                .map_unexpected_while(|| format!("object for entry {:?} not found", entry))?
+                .bytes_stream();
+
+            use futures::StreamExt;
+            Ok(util::into_box_byte_stream(res.map(|r| {
+                use std::io::{Error, ErrorKind};
+                r.map_err(|e| Error::new(ErrorKind::ConnectionAborted, e))
+            })))
+
+            // TODO this is still not correct, as it will include the git object header
+        })
+    }
+}

src/origin/mux.rs

@@ -3,171 +3,48 @@ use crate::{origin, util};
 
 pub struct Store<F, S>
 where
-    S: origin::Store + 'static,
     F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
 {
     mapping_fn: F,
-    stores: Vec<S>,
 }
 
 impl<F, S> Store<F, S>
 where
-    S: origin::Store + 'static,
+    S: origin::Store + Sync + Send + 'static,
     F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
 {
-    pub fn new(mapping_fn: F, stores: Vec<S>) -> Store<F, S> {
-        Store { mapping_fn, stores }
+    pub fn new(mapping_fn: F) -> Store<F, S> {
+        Store { mapping_fn }
     }
 }
 
 impl<F, S> origin::Store for Store<F, S>
 where
-    S: origin::Store + 'static,
+    S: origin::Store + Sync + Send + 'static,
     F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
 {
-    fn sync(&self, descr: &origin::Descr) -> Result<(), origin::SyncError> {
-        (self.mapping_fn)(descr)
-            .or_unexpected_while(format!("mapping {:?} to store", &descr))?
-            .sync(descr)
-    }
-
-    fn all_descrs(&self) -> Result<Vec<origin::Descr>, origin::AllDescrsError> {
-        let mut res = Vec::<origin::Descr>::new();
-
-        for store in self.stores.iter() {
-            store.all_descrs()?.into_iter().collect_into(&mut res);
-        }
-
-        Ok(res)
+    fn sync(&self, descr: &origin::Descr) -> util::BoxFuture<'_, Result<(), origin::SyncError>> {
+        let descr = descr.clone();
+        Box::pin(async move {
+            (self.mapping_fn)(&descr)
+                .or_unexpected_while(format!("mapping {:?} to store", &descr))?
+                .sync(&descr)
+                .await
+        })
     }
 
     fn get_file(
         &self,
         descr: &origin::Descr,
         path: &str,
-    ) -> Result<util::BoxByteStream, origin::GetFileError> {
-        (self.mapping_fn)(descr)
-            .or_unexpected_while(format!("mapping {:?} to store", &descr))?
-            .get_file(descr, path)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::origin;
-    use std::sync;
-
-    struct Harness {
-        descr_a: origin::Descr,
-        descr_b: origin::Descr,
-        descr_unknown: origin::Descr,
-        store_a: sync::Arc<sync::Mutex<origin::MockStore>>,
-        store_b: sync::Arc<sync::Mutex<origin::MockStore>>,
-        store: Box<dyn origin::Store>,
-    }
-
-    impl Harness {
-        fn new() -> Harness {
-            let descr_a = origin::Descr::Git {
-                url: "A".to_string(),
-                branch_name: "A".to_string(),
-            };
-
-            let descr_b = origin::Descr::Git {
-                url: "B".to_string(),
-                branch_name: "B".to_string(),
-            };
-
-            let store_a = origin::new_mock();
-            let store_b = origin::new_mock();
-
-            Harness {
-                descr_a: descr_a.clone(),
-                descr_b: descr_b.clone(),
-                descr_unknown: origin::Descr::Git {
-                    url: "X".to_string(),
-                    branch_name: "X".to_string(),
-                },
-                store_a: store_a.clone(),
-                store_b: store_b.clone(),
-                store: Box::from(super::Store::new(
-                    {
-                        let store_a = store_a.clone();
-                        let store_b = store_b.clone();
-                        move |descr| match descr {
-                            &origin::Descr::Git { ref url, .. } if url == "A" => {
-                                Some(store_a.clone())
-                            }
-                            &origin::Descr::Git { ref url, .. } if url == "B" => {
-                                Some(store_b.clone())
-                            }
-                            _ => None,
-                        }
-                    },
-                    vec![store_a.clone(), store_b.clone()],
-                )),
-            }
-        }
-    }
-
-    #[test]
-    fn sync() {
-        let h = Harness::new();
-
-        {
-            let descr_a = h.descr_a.clone();
-            h.store_a
-                .lock()
-                .unwrap()
-                .expect_sync()
-                .withf(move |descr: &origin::Descr| descr == &descr_a)
-                .times(1)
-                .return_const(Ok::<(), origin::SyncError>(()));
-        }
-
-        assert_eq!(Ok(()), h.store.sync(&h.descr_a));
-
-        {
-            let descr_b = h.descr_b.clone();
-            h.store_b
-                .lock()
-                .unwrap()
-                .expect_sync()
-                .withf(move |descr: &origin::Descr| descr == &descr_b)
-                .times(1)
-                .return_const(Ok::<(), origin::SyncError>(()));
-        }
-
-        assert_eq!(Ok(()), h.store.sync(&h.descr_b));
-
-        assert!(h.store.sync(&h.descr_unknown).is_err());
-    }
-
-    #[test]
-    fn all_descrs() {
-        let h = Harness::new();
-
-        h.store_a
-            .lock()
-            .unwrap()
-            .expect_all_descrs()
-            .times(1)
-            .return_const(Ok::<Vec<origin::Descr>, origin::AllDescrsError>(vec![h
-                .descr_a
-                .clone()]));
-
-        h.store_b
-            .lock()
-            .unwrap()
-            .expect_all_descrs()
-            .times(1)
-            .return_const(Ok::<Vec<origin::Descr>, origin::AllDescrsError>(vec![h
-                .descr_b
-                .clone()]));
-
-        assert_eq!(
-            Ok(vec![h.descr_a.clone(), h.descr_b.clone()]),
-            h.store.all_descrs(),
-        )
+    ) -> util::BoxFuture<Result<util::BoxByteStream, origin::GetFileError>> {
+        let descr = descr.clone();
+        let path = path.to_string();
+        Box::pin(async move {
+            (self.mapping_fn)(&descr)
+                .or_unexpected_while(format!("mapping {:?} to store", &descr))?
+                .get_file(&descr, &path)
+                .await
+        })
     }
 }

src/service/gemini.rs

@@ -98,11 +98,16 @@ impl Service {
         let path = service::append_index_to_path(req.path(), "index.gmi");
 
         use domain::manager::GetFileError;
-        let f = match self.domain_manager.get_file(settings, &path) {
+        let f = match self.domain_manager.get_file(settings, &path).await {
             Ok(f) => f,
             Err(GetFileError::FileNotFound) => {
                 return Ok(self.respond_conn(w, "51", "File not found", None).await?)
             }
+            Err(GetFileError::Unavailable) => {
+                return Ok(self
+                    .respond_conn(w, "43", "Content unavailable", None)
+                    .await?)
+            }
             Err(GetFileError::DescrNotSynced) => {
                 return Err(unexpected::Error::from(
                     format!(
@@ -117,7 +122,7 @@ impl Service {
                 // redirect so that the path has '/' appended to it, which will cause the server to
                 // check index.gmi within the path on the new page load.
                 let mut path = path.into_owned();
-                path.push_str("/");
+                path.push('/');
                 return Ok(self.respond_conn(w, "30", path.as_str(), None).await?);
             }
             Err(GetFileError::Unexpected(e)) => return Err(e.into()),

src/service/http.rs

@@ -218,9 +218,10 @@ impl Service {
         let path = service::append_index_to_path(req.uri().path(), "index.html");
 
         use domain::manager::GetFileError;
-        match self.domain_manager.get_file(&settings, &path) {
+        match self.domain_manager.get_file(&settings, &path).await {
             Ok(f) => self.serve(200, &path, Body::wrap_stream(f)),
             Err(GetFileError::FileNotFound) => self.render_error_page(404, "File not found"),
+            Err(GetFileError::Unavailable) => self.render_error_page(502, "Content unavailable"),
             Err(GetFileError::DescrNotSynced) => self.internal_error(
                 format!(
                     "Backend for {:?} has not yet been synced",
@@ -232,7 +233,7 @@ impl Service {
                 // redirect so that the path has '/' appended to it, which will cause the server to
                 // check index.html within the path on the new page load.
                 let mut path = path.into_owned();
-                path.push_str("/");
+                path.push('/');
                 self.render_redirect(
                     http::status::StatusCode::TEMPORARY_REDIRECT.into(),
                     path.as_str(),
@@ -408,6 +409,11 @@ impl Service {
                     .to_string(),
             ), false),
 
+            Err(domain::manager::SyncWithSettingsError::Unavailable) => (Some(
+                "Fetching the git repository failed; the server is not available or is not corectly serving the repository."
+                    .to_string(),
+            ), false),
+
             Err(domain::manager::SyncWithSettingsError::InvalidBranchName) => (Some(
                 "The git repository does not have a branch of the given name; please double check
                 that you input the correct name."

src/service/http/util.rs

@@ -1,7 +1,7 @@
 use std::convert::TryFrom;
 
 use serde::{Deserialize, Serialize};
-use serde_with::{serde_as, NoneAsEmptyString};
+use serde_with::{serde_as, DisplayFromStr, NoneAsEmptyString};
 
 use crate::{domain, error::unexpected, origin};
 
@@ -10,7 +10,8 @@ use crate::{domain, error::unexpected, origin};
 pub struct UrlEncodedDomainSettings {
     domain_setting_origin_descr_kind: String,
 
-    domain_setting_origin_descr_git_url: Option<String>,
+    #[serde_as(as = "Option<DisplayFromStr>")]
+    domain_setting_origin_descr_git_url: Option<origin::descr::GitUrl>,
     domain_setting_origin_descr_git_branch_name: Option<String>,
 
     domain_setting_origin_descr_proxy_url: Option<String>,

src/util.rs

@@ -33,4 +33,11 @@ pub fn parse_file<T: std::str::FromStr>(
 
 pub type BoxByteStream = futures::stream::BoxStream<'static, io::Result<bytes::Bytes>>;
 
+pub fn into_box_byte_stream<T>(v: T) -> BoxByteStream
+where
+    T: futures::stream::Stream<Item = std::io::Result<bytes::Bytes>> + Send + 'static,
+{
+    Box::into_pin(Box::new(v))
+}
+
 pub type BoxFuture<'a, O> = pin::Pin<Box<dyn futures::Future<Output = O> + Send + 'a>>;