Added reset-conn, conn-from-datoms and conn-from-db (closes ton…

…sky#45)
alexei-matveev · Jan 17, 2016 · a8da9eb · a8da9eb
1 parent 6ed256f
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - Can specify transaction number in `:db/add`
 - Can put datoms into transaction directly (issue #121: supports both addition and retration datoms, keeps tx number)
 - Added all `datascript.core` symbols to externs so they can be called directly from JS (e.g. in combination with mori, issue #139)
+- Added `reset-conn`, `conn-from-datoms` and `conn-from-db` (issue #45)
 
 # 0.14.0
 

diff --git a/src/datascript/core.cljc b/src/datascript/core.cljc
@@ -89,11 +89,16 @@
           :cljs (satisfies? cljs.core/IDeref conn))
     (db/db? @conn)))
 
+(defn ^:export conn-from-db [db]
+  (atom db :meta { :listeners (atom {}) }))
+
+(defn ^:export conn-from-datoms
+  ([datoms]        (conn-from-db (init-db datoms)))
+  ([datoms schema] (conn-from-db (init-db datoms schema))))
+
 (defn ^:export create-conn
-  ([] (create-conn db/default-schema))
-  ([schema]
-    (atom (empty-db schema)
-          :meta { :listeners  (atom {}) })))
+  ([]       (conn-from-db (empty-db)))
+  ([schema] (conn-from-db (empty-db schema))))
 
 (defn -transact! [conn tx-data tx-meta]
   {:pre [(conn? conn)]}
@@ -112,7 +117,22 @@
       (doseq [[_ callback] @(:listeners (meta conn))]
         (callback report))
       report)))
-
+
+(defn ^:export reset-conn!
+  ([conn db] (reset-conn! conn db nil))
+  ([conn db tx-meta]
+    (let [report (db/map->TxReport
+                  { :db-before @conn
+                    :db-after  db
+                    :tx-data   (concat
+                                 (map #(assoc % :added false) (datoms @conn :eavt))
+                                 (datoms db :eavt))
+                    :tx-meta   tx-meta})]
+      (reset! conn db)
+      (doseq [[_ callback] @(:listeners (meta conn))]
+        (callback report))
+      db)))
+
 (defn ^:export listen!
   ([conn callback] (listen! conn (rand) callback))
   ([conn key callback]

diff --git a/src/datascript/db.cljc b/src/datascript/db.cljc
@@ -133,7 +133,7 @@
         (-nth [this i not-found] (nth-datom this i not-found))
 
         IAssociative
-        (-assoc [d k v] (assoc-datom k))
+        (-assoc [d k v] (assoc-datom d k v))
 
         IPrintWithWriter
         (-pr-writer [d writer opts]
@@ -155,7 +155,7 @@
         (equiv [d o] (and (instance? Datom o) (equiv-datom d o)))
         (empty [d] (throw (UnsupportedOperationException. "empty is not supported on Datom")))
         (count [d] 5)
-        (cons [d [k v]] (assoc-datom k v))
+        (cons [d [k v]] (assoc-datom d k v))
 
         clojure.lang.Indexed
         (nth [this i]           (nth-datom this i))
@@ -168,7 +168,7 @@
         clojure.lang.Associative
         (entryAt [d k] (some->> (val-at-datom d k nil) (clojure.lang.MapEntry k)))
         (containsKey [e k] (#{:e :a :v :tx :added} k))
-        (assoc [d k v] (assoc-datom k v))
+        (assoc [d k v] (assoc-datom d k v))
         ]))
 
 (defn ^Datom datom

diff --git a/src/datascript/js.cljs b/src/datascript/js.cljs
@@ -97,6 +97,12 @@
 (defn ^:export create_conn [& [schema]]
   (d/create-conn (schema->clj schema)))
 
+(def ^:export conn_from_db d/conn-from-db)
+
+(defn ^:export conn_from_datoms
+  ([datoms]        (conn_from_db (init_db datoms)))
+  ([datoms schema] (conn_from_db (init_db datoms schema))))
+
 (defn ^:export db [conn]
   @conn)
 
@@ -108,6 +114,19 @@
       (callback report))
     report))
 
+(defn ^:export reset_conn [conn db & [tx-meta]]
+  (let [report #js { :db_before @conn
+                     :db_after  db
+                     :tx_data   (into-array
+                                  (concat
+                                    (map #(assoc % :added false) (d/datoms @conn :eavt))
+                                    (d/datoms db :eavt)))
+                     :tx_meta   tx-meta }]
+    (reset! conn db)
+    (doseq [[_ callback] @(:listeners (meta conn))]
+      (callback report))
+    db))
+
 (def ^:export listen d/listen!)
 
 (def ^:export unlisten d/unlisten!)

diff --git a/test/datascript/test.cljc b/test/datascript/test.cljc
@@ -6,6 +6,7 @@
 
     datascript.test.btset
     datascript.test.components
+    datascript.test.conn
     datascript.test.db
     datascript.test.entity
     datascript.test.explode

diff --git a/test/datascript/test/conn.cljc b/test/datascript/test/conn.cljc
@@ -0,0 +1,62 @@
+(ns datascript.test.conn
+  (:require
+    #?(:cljs [cljs.test    :as t :refer-macros [is are deftest testing]]
+       :clj  [clojure.test :as t :refer        [is are deftest testing]])
+    [datascript.core :as d]
+    [datascript.db :as db]
+    [datascript.test.core :as tdc]))
+
+(def schema { :aka { :db/cardinality :db.cardinality/many }})
+(def datoms #{(d/datom 1 :age  17)
+              (d/datom 1 :name "Ivan")})
+
+(deftest test-ways-to-create-conn
+  (let [conn (d/create-conn)]
+    (is (= #{} (set (d/datoms @conn :eavt))))
+    (is (= nil (:schema @conn))))
+
+  (let [conn (d/create-conn schema)]
+    (is (= #{} (set (d/datoms @conn :eavt))))
+    (is (= schema (:schema @conn))))
+
+  (let [conn (d/conn-from-datoms datoms)]
+    (is (= datoms (set (d/datoms @conn :eavt))))
+    (is (= nil (:schema @conn))))
+
+  (let [conn (d/conn-from-datoms datoms schema)]
+    (is (= datoms (set (d/datoms @conn :eavt))))
+    (is (= schema (:schema @conn))))
+
+  (let [conn (d/conn-from-db (d/init-db datoms))]
+    (is (= datoms (set (d/datoms @conn :eavt))))
+    (is (= nil (:schema @conn))))
+
+  (let [conn (d/conn-from-db (d/init-db datoms schema))]
+    (is (= datoms (set (d/datoms @conn :eavt))))
+    (is (= schema (:schema @conn)))))
+
+(deftest test-reset-conn!
+  (let [conn    (d/conn-from-datoms datoms schema)
+        report  (atom nil)
+        _       (d/listen! conn #(reset! report %))
+        datoms' #{(d/datom 1 :age 20)
+                  (d/datom 1 :sex :male)}
+        schema' { :email { :db/unique :db.unique/identity }}
+        db'     (d/init-db datoms' schema')]
+    (d/reset-conn! conn db' :meta)
+    (is (= datoms' (set (d/datoms @conn :eavt))))
+    (is (= schema' (:schema @conn)))
+
+    (let [{:keys [db-before db-after tx-data tx-meta]} @report]
+      (is (= datoms  (set (d/datoms db-before :eavt))))
+      (is (= schema  (:schema db-before)))
+      (is (= datoms' (set (d/datoms db-after :eavt))))
+      (is (= schema' (:schema db-after)))
+      (is (= :meta   tx-meta))
+      (is (= [[1 :age  17     false]
+              [1 :name "Ivan" false]
+              [1 :age  20     true]
+              [1 :sex  :male  true]]
+             (map (juxt :e :a :v :added) tx-data))))))
+
+
diff --git a/test/js/tests.js b/test/js/tests.js
@@ -200,6 +200,21 @@ function test_tx_report() {
   assert_eq(meta[0], {"some-meta": 1});
 }
 
+function test_conn() {
+  var datoms = [[1, "age",  17, tx0+1],
+                [1, "name", "Ivan", tx0+1]];
+  var conn = d.conn_from_datoms(datoms);
+  assert_eq_datoms(datoms, d.datoms(d.db(conn), ":eavt"));
+
+  conn = d.conn_from_db(d.init_db(datoms));
+  assert_eq_datoms(datoms, d.datoms(d.db(conn), ":eavt"));
+
+  var datoms2 = [[1, "age",  20, tx0+1],
+                 [1, "sex", "male", tx0+1]];
+  d.reset_conn(conn, d.init_db(datoms2));
+  assert_eq_datoms(datoms2, d.datoms(d.db(conn), ":eavt"));
+}
+
 function test_entity() {
   var schema = {"aka": {":db/cardinality": ":db.cardinality/many"}};
   var db = d.db_with(d.empty_db(schema), 
@@ -426,6 +441,7 @@ function test_datascript_js() {
                     test_dbfn_call,
                     test_schema,
                     test_tx_report,
+                    test_conn,
                     test_entity,
                     test_entity_refs,
                     test_pull,