1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
// 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 std;
use std::collections::HashMap;

use futures::{future, Future, Stream};
use hyper;
// TODO: enable TLS support; hurdle is cross-compiling openssl for Android.
// See https://github.com/mozilla/mentat/issues/569
// use hyper_tls;
use hyper::{Method, Request, StatusCode, Error as HyperError};
use hyper::header::{ContentType};
use rusqlite;
// TODO: https://github.com/mozilla/mentat/issues/570
// use serde_cbor;
use serde_json;
use tokio_core::reactor::Core;
use uuid::Uuid;

use core_traits::{
    Entid,
};

use metadata::SyncMetadataClient;
use metadata::HeadTrackable;
use schema::ensure_current_version;

use tolstoy_traits::errors::{
    TolstoyError,
    Result,
};

use tx_processor::{
    Processor,
    TxReceiver,
    TxPart,
};

use tx_mapper::TxMapper;

// TODO it would be nice to be able to pass
// in a logger into Syncer::flow; would allow for a "debug mode"
// and getting useful logs out of clients.
// See https://github.com/mozilla/mentat/issues/571
// Below is some debug Android-friendly logging:

// use std::os::raw::c_char;
// use std::os::raw::c_int;
// use std::ffi::CString;
// pub const ANDROID_LOG_DEBUG: i32 = 3;
// extern { pub fn __android_log_write(prio: c_int, tag: *const c_char, text: *const c_char) -> c_int; }

pub fn d(message: &str) {
    println!("d: {}", message);
    // let message = CString::new(message).unwrap();
    // let message = message.as_ptr();
    // let tag = CString::new("RustyToodle").unwrap();
    // let tag = tag.as_ptr();
    // unsafe { __android_log_write(ANDROID_LOG_DEBUG, tag, message) };
}

pub struct Syncer {}

// TODO this is sub-optimal, we don't need to walk the table
// to query the last thing in it w/ an index on tx!!
// but it's the hammer at hand!
// See https://github.com/mozilla/mentat/issues/572
struct InquiringTxReceiver {
    pub last_tx: Option<Entid>,
    pub is_done: bool,
}

impl InquiringTxReceiver {
    fn new() -> InquiringTxReceiver {
        InquiringTxReceiver {
            last_tx: None,
            is_done: false,
        }
    }
}

impl TxReceiver for InquiringTxReceiver {
    fn tx<T>(&mut self, tx_id: Entid, _datoms: &mut T) -> Result<()>
    where T: Iterator<Item=TxPart> {
        self.last_tx = Some(tx_id);
        Ok(())
    }

    fn done(&mut self) -> Result<()> {
        self.is_done = true;
        Ok(())
    }
}

struct UploadingTxReceiver<'c> {
    pub tx_temp_uuids: HashMap<Entid, Uuid>,
    pub is_done: bool,
    remote_client: &'c RemoteClient,
    remote_head: &'c Uuid,
    rolling_temp_head: Option<Uuid>,
}

impl<'c> UploadingTxReceiver<'c> {
    fn new(client: &'c RemoteClient, remote_head: &'c Uuid) -> UploadingTxReceiver<'c> {
        UploadingTxReceiver {
            tx_temp_uuids: HashMap::new(),
            remote_client: client,
            remote_head: remote_head,
            rolling_temp_head: None,
            is_done: false
        }
    }
}

impl<'c> TxReceiver for UploadingTxReceiver<'c> {
    fn tx<T>(&mut self, tx_id: Entid, datoms: &mut T) -> Result<()>
    where T: Iterator<Item=TxPart> {
        // Yes, we generate a new UUID for a given Tx, even if we might
        // already have one mapped locally. Pre-existing local mapping will
        // be replaced if this sync succeeds entirely.
        // If we're seeing this tx again, it implies that previous attempt
        // to sync didn't update our local head. Something went wrong last time,
        // and it's unwise to try to re-use these remote tx mappings.
        // We just leave garbage txs to be GC'd on the server.
        let tx_uuid = Uuid::new_v4();
        self.tx_temp_uuids.insert(tx_id, tx_uuid);
        let mut tx_chunks = vec![];

        // TODO separate bits of network work should be combined into single 'future'

        // Upload all chunks.
        for datom in datoms {
            let datom_uuid = Uuid::new_v4();
            tx_chunks.push(datom_uuid);
            d(&format!("putting chunk: {:?}, {:?}", &datom_uuid, &datom));
            // TODO switch over to CBOR once we're past debugging stuff.
            // See https://github.com/mozilla/mentat/issues/570
            // let cbor_val = serde_cbor::to_value(&datom)?;
            // self.remote_client.put_chunk(&datom_uuid, &serde_cbor::ser::to_vec_sd(&cbor_val)?)?;
            self.remote_client.put_chunk(&datom_uuid, &serde_json::to_string(&datom)?)?;
        }

        // Upload tx.
        // NB: At this point, we may choose to update remote & local heads.
        // Depending on how much we're uploading, and how unreliable our connection
        // is, this might be a good thing to do to ensure we make at least some progress.
        // Comes at a cost of possibly increasing racing against other clients.
        match self.rolling_temp_head {
            Some(parent) => {
                d(&format!("putting transaction: {:?}, {:?}, {:?}", &tx_uuid, &parent, &tx_chunks));
                self.remote_client.put_transaction(&tx_uuid, &parent, &tx_chunks)?;
                
            },
            None => {
                d(&format!("putting transaction: {:?}, {:?}, {:?}", &tx_uuid, &self.remote_head, &tx_chunks));
                self.remote_client.put_transaction(&tx_uuid, self.remote_head, &tx_chunks)?;
            }
        }

        d(&format!("updating rolling head: {:?}", tx_uuid));
        self.rolling_temp_head = Some(tx_uuid.clone());

        Ok(())
    }

    fn done(&mut self) -> Result<()> {
        self.is_done = true;
        Ok(())
    }
}

impl Syncer {
    fn upload_ours(db_tx: &mut rusqlite::Transaction, from_tx: Option<Entid>, remote_client: &RemoteClient, remote_head: &Uuid) -> Result<()> {
        let mut uploader = UploadingTxReceiver::new(remote_client, remote_head);
        Processor::process(db_tx, from_tx, &mut uploader)?;
        if !uploader.is_done {
            bail!(TolstoyError::TxProcessorUnfinished);
        }
        // Last tx uuid uploaded by the tx receiver.
        // It's going to be our new head.
        if let Some(last_tx_uploaded) = uploader.rolling_temp_head {
            // Upload remote head.
            remote_client.put_head(&last_tx_uploaded)?;

            // On succes:
            // - persist local mappings from the receiver
            // - update our local "remote head".
            TxMapper::set_bulk(db_tx, &uploader.tx_temp_uuids)?;
            SyncMetadataClient::set_remote_head(db_tx, &last_tx_uploaded)?;
        }

        Ok(())
    }

    pub fn flow(sqlite: &mut rusqlite::Connection, server_uri: &String, user_uuid: &Uuid) -> Result<()> {
        d(&format!("sync flowing"));

        ensure_current_version(sqlite)?;
        
        // TODO configure this sync with some auth data
        let remote_client = RemoteClient::new(server_uri.clone(), user_uuid.clone());
        let mut db_tx = sqlite.transaction()?;

        let remote_head = remote_client.get_head()?;
        d(&format!("remote head {:?}", remote_head));

        let locally_known_remote_head = SyncMetadataClient::remote_head(&db_tx)?;
        d(&format!("local head {:?}", locally_known_remote_head));

        // Local head: latest transaction that we have in the store,
        // but with one caveat: its tx might will not be mapped if it's
        // never been synced successfully.
        // In other words: if latest tx isn't mapped, then HEAD moved
        // since last sync and server needs to be updated.
        let mut inquiring_tx_receiver = InquiringTxReceiver::new();
        // TODO don't just start from the beginning... but then again, we should do this
        // without walking the table at all, and use the tx index.
        Processor::process(&db_tx, None, &mut inquiring_tx_receiver)?;
        if !inquiring_tx_receiver.is_done {
            bail!(TolstoyError::TxProcessorUnfinished);
        }
        let have_local_changes = match inquiring_tx_receiver.last_tx {
            Some(tx) => {
                match TxMapper::get(&db_tx, tx)? {
                    Some(_) => false,
                    None => true
                }
            },
            None => false
        };

        // Check if the server is empty - populate it.
        if remote_head == Uuid::nil() {
            d(&format!("empty server!"));
            Syncer::upload_ours(&mut db_tx, None, &remote_client, &remote_head)?;
        
        // Check if the server is the same as us, and if our HEAD moved.
        } else if locally_known_remote_head == remote_head {
            d(&format!("server unchanged since last sync."));
            
            if !have_local_changes {
                d(&format!("local HEAD did not move. Nothing to do!"));
                return Ok(());
            }

            d(&format!("local HEAD moved."));
            // TODO it's possible that we've successfully advanced remote head previously,
            // but failed to advance our own local head. If that's the case, and we can recognize it,
            // our sync becomes just bumping our local head. AFAICT below would currently fail.
            if let Some(upload_from_tx) = TxMapper::get_tx_for_uuid(&db_tx, &locally_known_remote_head)? {
                d(&format!("Fast-forwarding the server."));
                Syncer::upload_ours(&mut db_tx, Some(upload_from_tx), &remote_client, &remote_head)?;
            } else {
                d(&format!("Unable to fast-forward the server; missing local tx mapping"));
                bail!(TolstoyError::TxIncorrectlyMapped(0));
            }
            
        // We diverged from the server.
        // We'll need to rebase/merge ourselves on top of it.
        } else {
            d(&format!("server changed since last sync."));

            bail!(TolstoyError::NotYetImplemented(
                format!("Can't yet sync against changed server. Local head {:?}, remote head {:?}", locally_known_remote_head, remote_head)
            ));
        }

        // Commit everything, if there's anything to commit!
        // Any new tx->uuid mappings and the new HEAD. We're synced!
        db_tx.commit()?;

        Ok(())
    }
}

#[derive(Serialize,Deserialize)]
struct SerializedHead {
    head: Uuid
}

#[derive(Serialize)]
struct SerializedTransaction<'a> {
    parent: &'a Uuid,
    chunks: &'a Vec<Uuid>
}

struct RemoteClient {
    base_uri: String,
    user_uuid: Uuid
}


impl RemoteClient {
    fn new(base_uri: String, user_uuid: Uuid) -> Self {
        RemoteClient {
            base_uri: base_uri,
            user_uuid: user_uuid
        }
    }

    fn bound_base_uri(&self) -> String {
        // TODO escaping
        format!("{}/{}", self.base_uri, self.user_uuid)
    }

    fn get_uuid(&self, uri: String) -> Result<Uuid> {
        let mut core = Core::new()?;
        // TODO enable TLS, see https://github.com/mozilla/mentat/issues/569
        // let client = hyper::Client::configure()
        //     .connector(hyper_tls::HttpsConnector::new(4, &core.handle()).unwrap())
        //     .build(&core.handle());
        let client = hyper::Client::new(&core.handle());

        d(&format!("client"));

        let uri = uri.parse()?;

        d(&format!("parsed uri {:?}", uri));
        
        let work = client.get(uri).and_then(|res| {
            println!("Response: {}", res.status());

            res.body().concat2().and_then(move |body| {
                let head_json: SerializedHead = serde_json::from_slice(&body).map_err(|e| {
                    std::io::Error::new(std::io::ErrorKind::Other, e)
                })?;
                Ok(head_json)
            })
        });

        d(&format!("running..."));

        let head_json = core.run(work)?;
        d(&format!("got head: {:?}", &head_json.head));
        Ok(head_json.head)
    }

    fn put<T>(&self, uri: String, payload: T, expected: StatusCode) -> Result<()>
    where hyper::Body: std::convert::From<T>, {
        let mut core = Core::new()?;
        // TODO enable TLS, see https://github.com/mozilla/mentat/issues/569
        // let client = hyper::Client::configure()
        //     .connector(hyper_tls::HttpsConnector::new(4, &core.handle()).unwrap())
        //     .build(&core.handle());
        let client = hyper::Client::new(&core.handle());

        let uri = uri.parse()?;

        d(&format!("PUT {:?}", uri));

        let mut req = Request::new(Method::Put, uri);
        req.headers_mut().set(ContentType::json());
        req.set_body(payload);

        let put = client.request(req).and_then(|res| {
            let status_code = res.status();

            if status_code != expected {
                d(&format!("bad put response: {:?}", status_code));
                future::err(HyperError::Status)
            } else {
                future::ok(())
            }
        });

        core.run(put)?;
        Ok(())
    }

    fn put_transaction(&self, transaction_uuid: &Uuid, parent_uuid: &Uuid, chunks: &Vec<Uuid>) -> Result<()> {
        // {"parent": uuid, "chunks": [chunk1, chunk2...]}
        let transaction = SerializedTransaction {
            parent: parent_uuid,
            chunks: chunks
        };

        let uri = format!("{}/transactions/{}", self.bound_base_uri(), transaction_uuid);
        let json = serde_json::to_string(&transaction)?;
        d(&format!("serialized transaction: {:?}", json));
        self.put(uri, json, StatusCode::Created)
    }

    fn get_head(&self) -> Result<Uuid> {
        let uri = format!("{}/head", self.bound_base_uri());
        self.get_uuid(uri)
    }

    fn put_head(&self, uuid: &Uuid) -> Result<()> {
        // {"head": uuid}
        let head = SerializedHead {
            head: uuid.clone()
        };

        let uri = format!("{}/head", self.bound_base_uri());
        let json = serde_json::to_string(&head)?;
        d(&format!("serialized head: {:?}", json));
        self.put(uri, json, StatusCode::NoContent)
    }

    fn put_chunk(&self, chunk_uuid: &Uuid, payload: &String) -> Result<()> {
        let uri = format!("{}/chunks/{}", self.bound_base_uri(), chunk_uuid);
        d(&format!("serialized chunk: {:?}", payload));
        // TODO don't want to clone every datom!
        self.put(uri, payload.clone(), StatusCode::Created)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::borrow::Borrow;
    use std::str::FromStr;

    use edn;

    use mentat_db::debug::{TestConn};

    #[test]
    fn test_remote_client_bound_uri() {
        let user_uuid = Uuid::from_str(&"316ea470-ce35-4adf-9c61-e0de6e289c59").expect("uuid");
        let server_uri = String::from("https://example.com/api/0.1");
        let remote_client = RemoteClient::new(server_uri, user_uuid);
        assert_eq!("https://example.com/api/0.1/316ea470-ce35-4adf-9c61-e0de6e289c59", remote_client.bound_base_uri());
    }

    #[test]
    fn test_add() {
        let mut conn = TestConn::default();

        // Test inserting :db.cardinality/one elements.
        assert_transact!(conn, "[[:db/add 100 :db.schema/version 1]
                                 [:db/add 101 :db.schema/version 2]]");
        assert_matches!(conn.last_transaction(),
                        "[[100 :db.schema/version 1 ?tx true]
                          [101 :db.schema/version 2 ?tx true]
                          [?tx :db/txInstant ?ms ?tx true]]");
        assert_matches!(conn.datoms(),
                       "[[100 :db.schema/version 1]
                         [101 :db.schema/version 2]]");

        // Test inserting :db.cardinality/many elements.
        assert_transact!(conn, "[[:db/add 200 :db.schema/attribute 100]
                                 [:db/add 200 :db.schema/attribute 101]]");
        assert_matches!(conn.last_transaction(),
                        "[[200 :db.schema/attribute 100 ?tx true]
                          [200 :db.schema/attribute 101 ?tx true]
                          [?tx :db/txInstant ?ms ?tx true]]");
        assert_matches!(conn.datoms(),
                        "[[100 :db.schema/version 1]
                          [101 :db.schema/version 2]
                          [200 :db.schema/attribute 100]
                          [200 :db.schema/attribute 101]]");

        // Test replacing existing :db.cardinality/one elements.
        assert_transact!(conn, "[[:db/add 100 :db.schema/version 11]
                                 [:db/add 101 :db.schema/version 22]]");
        assert_matches!(conn.last_transaction(),
                        "[[100 :db.schema/version 1 ?tx false]
                          [100 :db.schema/version 11 ?tx true]
                          [101 :db.schema/version 2 ?tx false]
                          [101 :db.schema/version 22 ?tx true]
                          [?tx :db/txInstant ?ms ?tx true]]");
        assert_matches!(conn.datoms(),
                        "[[100 :db.schema/version 11]
                          [101 :db.schema/version 22]
                          [200 :db.schema/attribute 100]
                          [200 :db.schema/attribute 101]]");


        // Test that asserting existing :db.cardinality/one elements doesn't change the store.
        assert_transact!(conn, "[[:db/add 100 :db.schema/version 11]
                                 [:db/add 101 :db.schema/version 22]]");
        assert_matches!(conn.last_transaction(),
                        "[[?tx :db/txInstant ?ms ?tx true]]");
        assert_matches!(conn.datoms(),
                        "[[100 :db.schema/version 11]
                          [101 :db.schema/version 22]
                          [200 :db.schema/attribute 100]
                          [200 :db.schema/attribute 101]]");


        // Test that asserting existing :db.cardinality/many elements doesn't change the store.
        assert_transact!(conn, "[[:db/add 200 :db.schema/attribute 100]
                                 [:db/add 200 :db.schema/attribute 101]]");
        assert_matches!(conn.last_transaction(),
                        "[[?tx :db/txInstant ?ms ?tx true]]");
        assert_matches!(conn.datoms(),
                        "[[100 :db.schema/version 11]
                          [101 :db.schema/version 22]
                          [200 :db.schema/attribute 100]
                          [200 :db.schema/attribute 101]]");
    }
}