Return concrete TolstoyError error type out of tolstoy, and wrap dependency errors r=nalexander

This is inline with the rest of mentat, and is useful for upcoming work.

src/errors.rs

@@ -15,6 +15,7 @@ use std; // To refer to std::result::Result.
 use std::collections::BTreeSet;
 
 use rusqlite;
+use uuid;
 
 use edn;
 
@@ -30,6 +31,9 @@ use mentat_query_projector;
 use mentat_query_pull;
 use mentat_sql;
 
+#[cfg(feature = "syncable")]
+use mentat_tolstoy;
+
 pub type Result<T> = std::result::Result<T, MentatError>;
 
 #[macro_export]
@@ -80,6 +84,11 @@ pub enum MentatError {
     #[fail(display = "provided value of type {} doesn't match attribute value type {}", _0, _1)]
     ValueTypeMismatch(ValueType, ValueType),
 
+    /// We're just not done yet.  Message that the feature is recognized but not yet
+    /// implemented.
+    #[fail(display = "not yet implemented: {}", _0)]
+    NotYetImplemented(String),
+
     #[fail(display = "{}", _0)]
     IoError(#[cause] std::io::Error),
 
@@ -103,8 +112,15 @@ pub enum MentatError {
     #[fail(display = "{}", _0)]
     PullError(#[cause] mentat_query_pull::PullError),
 
+    #[fail(display = "{}", _0)]
+    UuidError(#[cause] uuid::ParseError),
+
     #[fail(display = "{}", _0)]
     SQLError(#[cause] mentat_sql::SQLError),
+
+    #[cfg(feature = "syncable")]
+    #[fail(display = "{}", _0)]
+    TolstoyError(#[cause] mentat_tolstoy::TolstoyError),
 }
 
 impl From<std::io::Error> for MentatError {
@@ -154,3 +170,16 @@ impl From<mentat_sql::SQLError> for MentatError {
         MentatError::SQLError(error)
     }
 }
+
+#[cfg(feature = "syncable")]
+impl From<mentat_tolstoy::TolstoyError> for MentatError {
+    fn from(error: mentat_tolstoy::TolstoyError) -> MentatError {
+        MentatError::TolstoyError(error)
+    }
+}
+
+impl From<uuid::ParseError> for MentatError {
+    fn from(error: uuid::ParseError) -> MentatError {
+        MentatError::UuidError(error)
+    }
+}

src/store.rs

@@ -234,7 +234,7 @@ impl Pullable for Store {
 }
 
 impl Syncable for Store {
-    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::failure::Error> {
+    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::errors::MentatError> {
         let uuid = Uuid::parse_str(&user_uuid).map_err(|_| MentatError::BadUuid(user_uuid.clone()))?;
         Ok(Syncer::flow(&mut self.sqlite, server_uri, &uuid)?)
     }

src/sync.rs

@@ -0,0 +1,142 @@
+// Copyright 2018 Mozilla
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+// this file except in compliance with the License. You may obtain a copy of the
+// License at http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+use uuid::Uuid;
+
+use rusqlite;
+
+use conn::{
+    Conn,
+    InProgress,
+};
+
+use errors::{
+    Result,
+};
+
+use mentat_core::{
+    KnownEntid,
+};
+use mentat_db::{
+    renumber,
+    PartitionMap,
+};
+
+use entity_builder::{
+    BuildTerms,
+    TermBuilder,
+};
+
+use mentat_tolstoy::{
+    Syncer,
+    SyncMetadataClient,
+    SyncResult,
+    Tx,
+    TxMapper,
+    TolstoyError,
+};
+
+pub trait Syncable {
+    fn sync(&mut self, server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::errors::MentatError>;
+}
+
+fn fast_forward_local<'a, 'c>(in_progress: &mut InProgress<'a, 'c>, txs: Vec<Tx>) -> Result<Option<PartitionMap>> {
+    let mut last_tx = None;
+
+    // During fast-forwarding, we will insert datoms with known entids
+    // which, by definition, fall outside of our user partition.
+    // Once we've done with insertion, we need to ensure that user
+    // partition's next allocation will not overlap with just-inserted datoms.
+    // To allow for "holes" in the user partition (due to data excision),
+    // we track the highest incoming entid we saw, and expand our
+    // local partition to match.
+    // In absence of excision and implementation bugs, this should work
+    // just as if we counted number of incoming entids and expanded by
+    // that number instead.
+    let mut last_encountered_partition_map = None;
+
+    for tx in txs {
+        let mut builder = TermBuilder::new();
+
+        last_encountered_partition_map = match tx.parts[0].partitions.clone() {
+            Some(parts) => Some(parts),
+            None => bail!(TolstoyError::BadServerState("Missing partition map in incoming transaction".to_string()))
+        };
+
+        for part in tx.parts {
+            if part.added {
+                builder.add(KnownEntid(part.e), KnownEntid(part.a), part.v)?;
+            } else {
+                builder.retract(KnownEntid(part.e), KnownEntid(part.a), part.v)?;
+            }
+        }
+
+        let report = in_progress.transact_builder(builder)?;
+
+        last_tx = Some((report.tx_id, tx.tx.clone()));
+    }
+
+    // We've just transacted a new tx, and generated a new tx entid.  Map it to the corresponding
+    // incoming tx uuid, advance our "locally known remote head".
+    if let Some((entid, uuid)) = last_tx {
+        SyncMetadataClient::set_remote_head(&mut in_progress.transaction, &uuid)?;
+        TxMapper::set_tx_uuid(&mut in_progress.transaction, entid, &uuid)?;
+    }
+
+    Ok(last_encountered_partition_map)
+}
+
+impl Conn {
+    pub(crate) fn sync(&mut self,
+                       sqlite: &mut rusqlite::Connection,
+                       server_uri: &String, user_uuid: &String) -> ::std::result::Result<(), ::errors::MentatError> {
+        let uuid = Uuid::parse_str(&user_uuid)?;
+
+        // Take an IMMEDIATE transaction right away.  We have an SQL transaction, and complete
+        // control over the `Conn` metadata at this point, just like `transact()`.
+        let mut in_progress = self.begin_transaction(sqlite)?;
+
+        let sync_result = Syncer::flow(&mut in_progress.transaction, server_uri, &uuid)?;
+        let mut incoming_partition = None;
+
+        match sync_result {
+            SyncResult::EmptyServer => (),
+            SyncResult::NoChanges => (),
+            SyncResult::ServerFastForward => (),
+            SyncResult::Merge => bail!(TolstoyError::NotYetImplemented(
+                format!("Can't sync against diverged local.")
+            )),
+            SyncResult::LocalFastForward(txs) => {
+                incoming_partition = fast_forward_local(&mut in_progress, txs)?;
+                ()
+            },
+            SyncResult::BadServerState => bail!(TolstoyError::NotYetImplemented(
+                format!("Bad server state.")
+            )),
+            SyncResult::AdoptedRemoteOnFirstSync => (),
+            SyncResult::IncompatibleBootstrapSchema => bail!(TolstoyError::NotYetImplemented(
+                format!("IncompatibleBootstrapSchema.")
+            )),
+        }
+
+        match incoming_partition {
+            Some(incoming) => {
+                let root = SyncMetadataClient::get_partitions(&in_progress.transaction, true)?;
+                let current = SyncMetadataClient::get_partitions(&in_progress.transaction, false)?;
+                let updated_db = renumber(&in_progress.transaction, &root, &current, &incoming)?;
+                in_progress.partition_map = updated_db.partition_map;
+                ()
+            },
+            None => ()
+        }
+
+        in_progress.commit()
+    }
+}

tolstoy/src/errors.rs

@@ -10,7 +10,13 @@
 
 #![allow(dead_code)]
 
-use failure::Error;
+use std;
+use rusqlite;
+use uuid;
+use hyper;
+use serde_json;
+
+use mentat_db;
 
 #[macro_export]
 macro_rules! bail {
@@ -19,7 +25,7 @@ macro_rules! bail {
     )
 }
 
-pub type Result<T> = ::std::result::Result<T, Error>;
+pub type Result<T> = ::std::result::Result<T, TolstoyError>;
 
 #[derive(Debug, Fail)]
 pub enum TolstoyError {
@@ -40,4 +46,70 @@ pub enum TolstoyError {
 
     #[fail(display = "not yet implemented: {}", _0)]
     NotYetImplemented(String),
+
+    #[fail(display = "{}", _0)]
+    DbError(#[cause] mentat_db::DbError),
+
+    #[fail(display = "{}", _0)]
+    SerializationError(#[cause] serde_json::Error),
+
+    // It would be better to capture the underlying `rusqlite::Error`, but that type doesn't
+    // implement many useful traits, including `Clone`, `Eq`, and `PartialEq`.
+    #[fail(display = "SQL error: _0")]
+    RusqliteError(String),
+
+    #[fail(display = "{}", _0)]
+    IoError(#[cause] std::io::Error),
+
+    #[fail(display = "{}", _0)]
+    UuidError(#[cause] uuid::ParseError),
+
+    #[fail(display = "{}", _0)]
+    NetworkError(#[cause] hyper::Error),
+
+    #[fail(display = "{}", _0)]
+    UriError(#[cause] hyper::error::UriError),
 }
+
+impl From<mentat_db::DbError> for TolstoyError {
+    fn from(error: mentat_db::DbError) -> TolstoyError {
+        TolstoyError::DbError(error)
+    }
+}
+
+impl From<serde_json::Error> for TolstoyError {
+    fn from(error: serde_json::Error) -> TolstoyError {
+        TolstoyError::SerializationError(error)
+    }
+}
+
+impl From<rusqlite::Error> for TolstoyError {
+    fn from(error: rusqlite::Error) -> TolstoyError {
+        TolstoyError::RusqliteError(error.to_string())
+    }
+}
+
+impl From<std::io::Error> for TolstoyError {
+    fn from(error: std::io::Error) -> TolstoyError {
+        TolstoyError::IoError(error)
+    }
+}
+
+impl From<uuid::ParseError> for TolstoyError {
+    fn from(error: uuid::ParseError) -> TolstoyError {
+        TolstoyError::UuidError(error)
+    }
+}
+
+impl From<hyper::Error> for TolstoyError {
+    fn from(error: hyper::Error) -> TolstoyError {
+        TolstoyError::NetworkError(error)
+    }
+}
+
+impl From<hyper::error::UriError> for TolstoyError {
+    fn from(error: hyper::error::UriError) -> TolstoyError {
+        TolstoyError::UriError(error)
+    }
+}
+