(#2839) - Implement revs_limit

docs/_includes/api/create_database.html

@@ -14,6 +14,7 @@
 
 * `auto_compaction`: This turns on auto compaction, which means `compact()` is called after every change to the database. Defaults to `false`.
 * `adapter`: One of `'idb'`, `'leveldb'`, `'websql'`, or `'http'`. If unspecified, PouchDB will infer this automatically, preferring IndexedDB to WebSQL in browsers that support both (i.e. Chrome, Opera and Android 4.4+).
+* `revs_limit`: Specify how many old revisions we keep track (not a copy) of.
 
 **Options for remote databases:**
 

lib/adapters/idb/bulkDocs.js

@@ -24,7 +24,7 @@ var encodeMetadata = idbUtils.encodeMetadata;
 var idbError = idbUtils.idbError;
 var openTransactionSafely = idbUtils.openTransactionSafely;
 
-function idbBulkDocs(req, opts, api, idb, Changes, callback) {
+function idbBulkDocs(dbOpts, req, opts, api, idb, Changes, callback) {
   var docInfos = req.docs;
   var txn;
   var docStore;
@@ -91,8 +91,8 @@ function idbBulkDocs(req, opts, api, idb, Changes, callback) {
   }
 
   function idbProcessDocs() {
-
-    processDocs(docInfos, api, fetchedDocs, txn, results, writeDoc, opts);
+    processDocs(dbOpts.revs_limit, docInfos, api, fetchedDocs,
+                txn, results, writeDoc, opts);
   }
 
   function fetchExistingDocs() {

lib/adapters/idb/index.js

@@ -289,8 +289,8 @@ function init(api, opts, callback) {
     callback(null, api._meta.instanceId);
   });
 
-  api._bulkDocs = function idb_bulkDocs(req, opts, callback) {
-    idbBulkDocs(req, opts, api, idb, IdbPouch.Changes, callback);
+  api._bulkDocs = function idb_bulkDocs(req, reqOpts, callback) {
+    idbBulkDocs(opts, req, reqOpts, api, idb, IdbPouch.Changes, callback);
   };
 
   // First we look up the metadata in the ids database, then we fetch the

lib/adapters/leveldb/index.js

@@ -160,6 +160,7 @@ function LevelPouch(opts, callback) {
   var api = this;
   var instanceId;
   var stores = {};
+  var revLimit = opts.revs_limit;
   var db;
   var name = opts.name;
   if (typeof opts.createIfMissing === 'undefined') {
@@ -822,8 +823,8 @@ function LevelPouch(opts, callback) {
         if (err) {
           return callback(err);
         }
-        processDocs(docInfos, api, fetchedDocs, txn, results, writeDoc,
-          opts, finish);
+        processDocs(revLimit, docInfos, api, fetchedDocs, txn, results,
+                    writeDoc, opts, finish);
       });
     });
   });

lib/adapters/websql/bulkDocs.js

@@ -24,7 +24,7 @@ var stringifyDoc = websqlUtils.stringifyDoc;
 var compactRevs = websqlUtils.compactRevs;
 var unknownError = websqlUtils.websqlError;
 
-function websqlBulkDocs(req, opts, api, db, Changes, callback) {
+function websqlBulkDocs(dbOpts, req, opts, api, db, Changes, callback) {
   var newEdits = opts.new_edits;
   var userDocs = req.docs;
 
@@ -257,7 +257,8 @@ function websqlBulkDocs(req, opts, api, db, Changes, callback) {
   }
 
   function websqlProcessDocs() {
-    processDocs(docInfos, api, fetchedDocs, tx, results, writeDoc, opts);
+    processDocs(dbOpts.revs_limit, docInfos, api, fetchedDocs, tx,
+                results, writeDoc, opts);
   }
 
   function fetchExistingDocs(callback) {

lib/adapters/websql/index.js

@@ -549,8 +549,8 @@ function WebSqlPouch(opts, callback) {
     }, websqlError(callback));
   };
 
-  api._bulkDocs = function (req, opts, callback) {
-    websqlBulkDocs(req, opts, api, db, WebSqlPouch.Changes, callback);
+  api._bulkDocs = function (req, reqOpts, callback) {
+    websqlBulkDocs(opts, req, reqOpts, api, db, WebSqlPouch.Changes, callback);
   };
 
   api._get = function (id, opts, callback) {

lib/deps/docs/processDocs.js

@@ -9,8 +9,11 @@ var merge = require('../../deps/merge');
 var collections = require('pouchdb-collections');
 var Map = collections.Map;
 
-function processDocs(docInfos, api, fetchedDocs, tx, results, writeDoc, opts,
-                     overallCallback) {
+function processDocs(revLimit, docInfos, api, fetchedDocs, tx, results,
+                     writeDoc, opts, overallCallback) {
+
+  // Default to 1000 locally
+  revLimit = revLimit || 1000;
 
   function insertDoc(docInfo, resultsIdx, callback) {
     // Cant insert new deleted documents
@@ -77,11 +80,11 @@ function processDocs(docInfos, api, fetchedDocs, tx, results, writeDoc, opts,
       var resultsIdx = value[1];
 
       if (fetchedDocs.has(id)) {
-        updateDoc(fetchedDocs.get(id), currentDoc, results,
+        updateDoc(revLimit, fetchedDocs.get(id), currentDoc, results,
           resultsIdx, docWritten, writeDoc, newEdits);
       } else {
         // Ensure stemming applies to new writes as well
-        var merged = merge([], currentDoc.metadata.rev_tree[0], 1000);
+        var merged = merge([], currentDoc.metadata.rev_tree[0], revLimit);
         currentDoc.metadata.rev_tree = merged.tree;
         insertDoc(currentDoc, resultsIdx, docWritten);
       }

lib/deps/docs/updateDoc.js

@@ -7,7 +7,8 @@ var calculateWinningRev = require('../../deps/merge/winningRev');
 var merge = require('../../deps/merge');
 var revExists = require('../../deps/merge/revExists');
 
-function updateDoc(prev, docInfo, results, i, cb, writeDoc, newEdits) {
+function updateDoc(revLimit, prev, docInfo, results,
+                   i, cb, writeDoc, newEdits) {
 
   if (revExists(prev.rev_tree, docInfo.metadata.rev)) {
     results[i] = docInfo;
@@ -29,7 +30,7 @@ function updateDoc(prev, docInfo, results, i, cb, writeDoc, newEdits) {
     docInfo = parseDoc(newDoc, newEdits);
   }
 
-  var merged = merge(prev.rev_tree, docInfo.metadata.rev_tree[0], 1000);
+  var merged = merge(prev.rev_tree, docInfo.metadata.rev_tree[0], revLimit);
 
   var inConflict = newEdits && (((previouslyDeleted && deleted) ||
     (!previouslyDeleted && merged.conflicts !== 'new_leaf') ||
@@ -70,4 +71,4 @@ function updateDoc(prev, docInfo, results, i, cb, writeDoc, newEdits) {
     true, delta, i, cb);
 }
 
-module.exports = updateDoc;
+module.exports = updateDoc;

tests/integration/test.bulk_docs.js

@@ -958,5 +958,44 @@ adapters.forEach(function (adapter) {
       });
     });
 
+    it('2839 implement revs_limit', function (done) {
+
+      // We only implement revs_limit locally
+      if (adapter === 'http') {
+        return done();
+      }
+
+      var LIMIT = 50;
+      var db = new PouchDB(dbs.name, {revs_limit: LIMIT});
+
+      // simulate 5000 normal commits with two conflicts at the very end
+      function uuid() {
+        return PouchDB.utils.uuid(32, 16).toLowerCase();
+      }
+
+      var numRevs = 5000;
+      var uuids = [];
+      for (var i = 0; i < numRevs - 1; i++) {
+        uuids.push(uuid());
+      }
+      var conflict1 = 'a' + uuid();
+      var doc1 = {
+        _id: 'doc',
+        _rev: numRevs + '-' + conflict1,
+        _revisions: {
+          start: numRevs,
+          ids: [conflict1].concat(uuids)
+        }
+      };
+
+      db.bulkDocs([doc1], {new_edits: false}).then(function () {
+        return db.get('doc', {revs: true});
+      }).then(function (doc) {
+        doc._revisions.ids.length.should.equal(LIMIT);
+        done();
+      }).catch(done);
+    });
+
+
   });
 });