From e8686c29f798d6ac3f76cb5275ca0498b288f1e4 Mon Sep 17 00:00:00 2001
From: Rafael Weinstein <rafael@atticlabs.io>
Date: Mon, 20 Jun 2016 10:22:46 -0700
Subject: [PATCH] Remove Set.intersect (#1852)

Remove Set.intersect
---
 js/src/set-test.js | 59 ------------------------------
 js/src/set.js      | 91 ----------------------------------------------
 2 files changed, 150 deletions(-)

diff --git a/js/src/set-test.js b/js/src/set-test.js
index c628ee66bf..d41865f728 100644
--- a/js/src/set-test.js
+++ b/js/src/set-test.js
@@ -511,33 +511,6 @@ suite('CompoundSet', () => {
     });
   });
 
-  async function testIntersect(expect: Array<string>, seqs: Array<Array<string>>) {
-    const first = build(db, seqs[0]);
-    const sets:Array<Set> = [];
-    for (let i = 1; i < seqs.length; i++) {
-      sets.push(build(db, seqs[i]));
-    }
-
-    const result = await first.intersect(...sets);
-    const actual = [];
-    await result.forEach(v => { actual.push(v); });
-    assert.deepEqual(expect, actual);
-  }
-
-  test('LONG: intersect', async () => {
-    await testIntersect(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        [['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'], ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']]);
-    await testIntersect(['a', 'h'], [['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'], ['a', 'h', 'i', 'j', 'k', 'l', 'm', 'n']]);
-    await testIntersect(['d', 'e', 'f', 'g', 'h'], [['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        ['d', 'e', 'f', 'g', 'h', 'i', 'j', 'k']]);
-    await testIntersect(['h'], [['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        ['d', 'e', 'f', 'g', 'h', 'i', 'j', 'k'], ['h', 'i', 'j', 'k', 'l', 'm', 'n', 'o']]);
-    await testIntersect([], [['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'],
-        ['d', 'e', 'f', 'g', 'h', 'i', 'j', 'k'], ['i', 'j', 'k', 'l', 'm', 'n', 'o', 'p']]);
-  });
-
   test('iterator at 0', async () => {
     const test = async (expected, items) => {
       const set = new Set(items);
@@ -679,36 +652,4 @@ suite('CompoundSet', () => {
     await t(10, SetLeafSequence);
     await t(100, OrderedMetaSequence);
   });
-
-  test('Type after mutations - interesect', async () => {
-    async function t(n, c) {
-      const nums: any = intSequence(n);
-      const strings = nums.map(n => String.fromCodePoint(n));
-      const combined = nums.concat(strings);
-
-      const numSet = new Set(nums);
-      assert.equal(numSet.size, n);
-      assert.instanceOf(numSet.sequence, c);
-      assert.isTrue(equals(numSet.type, makeSetType(numberType)));
-
-      const stringSet = new Set(strings);
-      assert.equal(stringSet.size, n);
-      assert.instanceOf(stringSet.sequence, c);
-      assert.isTrue(equals(stringSet.type, makeSetType(stringType)));
-
-      const combinedSet = new Set(combined);
-      assert.equal(combinedSet.size, 2 * n);
-      assert.instanceOf(combinedSet.sequence, c);
-      assert.isTrue(equals(combinedSet.type, makeSetType(makeUnionType([numberType, stringType]))));
-
-      const s = await combinedSet.intersect(numSet);
-      assert.isTrue(equals(s, numSet));
-
-      const s2 = await combinedSet.intersect(stringSet);
-      assert.isTrue(equals(s2, stringSet));
-    }
-
-    await t(10, SetLeafSequence);
-    await t(100, OrderedMetaSequence);
-  });
 });
diff --git a/js/src/set.js b/js/src/set.js
index 5ff7957de0..c614a338e8 100644
--- a/js/src/set.js
+++ b/js/src/set.js
@@ -155,37 +155,6 @@ export default class Set<T: Value> extends Collection<OrderedSequence> {
     return this.sequence.numLeaves;
   }
 
-  async intersect(...sets: Array<Set<T>>): Promise<Set<T>> {
-    if (sets.length === 0) {
-      return this;
-    }
-
-    let cursor = await this.sequence.newCursorAt(null);
-    if (!cursor.valid) {
-      return this;
-    }
-
-    const values: Array<T> = [];
-
-    for (let i = 0; cursor.valid && i < sets.length; i++) {
-      const first = cursor.getCurrent();
-      const next = await sets[i].sequence.newCursorAt(first);
-      if (!next.valid) {
-        break;
-      }
-
-      cursor = new SetIntersectionCursor(cursor, next);
-      await cursor.align();
-    }
-
-    while (cursor.valid) {
-      values.push(cursor.getCurrent());
-      await cursor.advance();
-    }
-
-    return new Set(values);
-  }
-
   /**
    * Returns a 2-tuple [added, removed] sorted values.
    */
@@ -211,63 +180,3 @@ export class SetLeafSequence<K: Value> extends OrderedSequence<K, K> {
     return getValueChunks(this.items);
   }
 }
-
-type OrderedCursor<K: Value> = {
-  valid: boolean;
-  getCurrent(): K;
-  advanceTo(key: K): Promise<boolean>;
-  advance(): Promise<boolean>;
-}
-
-class SetIntersectionCursor<K: Value> {
-  s1: OrderedCursor<K>;
-  s2: OrderedCursor<K>;
-  valid: boolean;
-
-  constructor(s1: OrderedCursor<K>, s2: OrderedCursor<K>) {
-    invariant(s1.valid && s2.valid);
-    this.s1 = s1;
-    this.s2 = s2;
-    this.valid = true;
-  }
-
-  getCurrent(): K {
-    invariant(this.valid);
-    return this.s1.getCurrent();
-  }
-
-  async align(): Promise<boolean> {
-    let v1 = this.s1.getCurrent();
-    let v2 = this.s2.getCurrent();
-
-    let i;
-    while ((i = compare(v1, v2)) !== 0) {
-      if (i < 0) {
-        if (!await this.s1.advanceTo(v2)) {
-          return this.valid = false;
-        }
-
-        v1 = this.s1.getCurrent();
-        continue;
-      }
-
-      if (!await this.s2.advanceTo(v1)) {
-        return this.valid = false;
-      }
-
-      v2 = this.s2.getCurrent();
-    }
-
-    return this.valid = true;
-  }
-
-  async advanceTo(key: K): Promise<boolean> {
-    invariant(this.valid);
-    return this.valid = await this.s1.advanceTo(key) && await this.align();
-  }
-
-  async advance(): Promise<boolean> {
-    invariant(this.valid);
-    return this.valid = await this.s1.advance() && await this.align();
-  }
-}