Use FTS to do partial matching

search/ui-android/src/main/java/com/jakewharton/sdksearch/search/ui/ItemViewHolder.kt

@@ -18,6 +18,7 @@ import androidx.core.text.inSpans
 import androidx.core.text.set
 import androidx.core.text.toSpannable
 import com.jakewharton.sdksearch.store.Item
+import com.jakewharton.sdksearch.store.asTerms
 import kotlin.LazyThreadSafetyMode.NONE
 
 internal class ItemViewHolder(
@@ -105,8 +106,19 @@ internal class ItemViewHolder(
     }
 
     val className = item.className.toSpannable()
-    val start = item.className.indexOf(query, ignoreCase = true)
-    className[start, start + query.length] = StyleSpan(BOLD)
+    query.asTerms().fold(0) { lastIndex, term ->
+      var start = item.className.indexOf(term, ignoreCase = term[0].isLowerCase(), startIndex = lastIndex)
+      if (start == -1) {
+        // Find it always ignoring case - there are some situations that we don't account for like
+        // the 'x' in R.xml
+        start = item.className.indexOf(term, ignoreCase = true, startIndex = lastIndex)
+      }
+      if (start == -1) {
+        throw IllegalStateException("Couldnt find term $term for item $item starting at $lastIndex")
+      }
+      className[start, start + term.length] = StyleSpan(BOLD)
+      return@fold start + 1
+    }
 
     var dotIndex = item.className.indexOf('.')
     while (dotIndex >= 0) {

store/android/src/androidTest/java/com/jakewharton/sdksearch/store/ItemStoreTest.kt

@@ -49,7 +49,6 @@ class ItemStoreTest {
     ))
 
     val item2 = query.receive().single()
-    assertEquals(id, item2.id)
     assertEquals("com.example", item2.packageName)
     assertEquals("One", item2.className)
     assertEquals("two.html", item2.link)
@@ -100,4 +99,28 @@ class ItemStoreTest {
       it.cancel()
     }
   }
+
+  @Test fun partialMatching() = runBlocking<Unit> {
+    itemStore.updateItems(listOf(
+        ItemUtil.createForInsert("com.example.ConstraintLayout", "constraint.html", null),
+        ItemUtil.createForInsert("com.example.ConcurrentLinkedDeque", "concurrent.html", null)
+    ))
+
+    itemStore.queryItems("ConL").also {
+      val results = it.receive()
+      assertEquals("ConstraintLayout", results[0].className)
+      assertEquals("ConcurrentLinkedDeque", results[1].className)
+      it.cancel()
+    }
+
+    itemStore.queryItems("ConLa").also {
+      assertEquals("ConstraintLayout", it.receive().single().className)
+      it.cancel()
+    }
+
+    itemStore.queryItems("Conla").also {
+      assertEquals(0, it.receive().size)
+      it.cancel()
+    }
+  }
 }

store/android/src/main/java/com/jakewharton/sdksearch/store/SqlItemStore.kt

@@ -6,6 +6,7 @@ import com.squareup.sqldelight.runtime.coroutines.mapToList
 import javax.inject.Inject
 import javax.inject.Singleton
 import kotlin.coroutines.experimental.CoroutineContext
+import kotlinx.coroutines.experimental.channels.ReceiveChannel
 
 @Singleton
 internal class SqlItemStore @Inject constructor(
@@ -15,21 +16,18 @@ internal class SqlItemStore @Inject constructor(
   override suspend fun updateItems(items: List<Item>) {
     db.transaction {
       for (item in items) {
-        val affected = db.updateItem(item.deprecated, item.link, item.packageName, item.className)
-        if (affected == 0L) {
-          db.insertItem(item.packageName, item.className, item.deprecated, item.link)
-        }
+        db.insertItem(item.packageName, item.className, item.deprecated, item.link)
+        db.insertItemIndex(item.className.asTerms().joinToString(" "))
       }
     }
   }
 
-  override fun queryItems(term: String) =
-      db.queryTerm(term.escapeLike('\\')).asChannel(context).mapToList()
-
-  private fun String.escapeLike(escapeChar: Char) =
-      this.replace("$escapeChar", "$escapeChar$escapeChar")
-          .replace("%", "$escapeChar%")
-          .replace("_", "${escapeChar}_")
+  override fun queryItems(term: String): ReceiveChannel<List<Item>> {
+    val terms = term.asTerms().joinToString(" ") { "$it*" }
+    return db.queryTerm("\"$terms\"")
+        .asChannel(context)
+        .mapToList()
+  }
 
   override fun count() = db.count().asChannel(context).mapToOne()
 }

store/src/main/kotlin/com/jakewharton/sdksearch/store/QueryTerms.kt

@@ -0,0 +1,26 @@
+package com.jakewharton.sdksearch.store
+
+fun String.asTerms(): List<String> {
+  var splitNext = false
+  return this.fold(emptyList()) { segments, character ->
+    // Fts cant handle these. Encode them as their unicode
+    when (character) {
+      '%' -> return@fold segments + "U0025"
+      '_' -> return@fold segments + "U005F"
+      '\\' -> return@fold segments + "U005C"
+    }
+
+    if (character !in 'A'..'Z' && character !in 'a'..'z') {
+      splitNext = true
+      return@fold segments
+    }
+
+
+    val lastSegment = segments.lastOrNull() ?: return@fold listOf(character.toString())
+    if (character.toLowerCase() == character && !splitNext) {
+      return@fold segments.dropLast(1) + (lastSegment + character)
+    }
+    splitNext = false
+    return@fold segments + character.toString()
+  }
+}

store/src/main/sqldelight/com/jakewharton/sdksearch/store/Item.sq

@@ -10,31 +10,21 @@ CREATE TABLE item(
 
 CREATE VIRTUAL TABLE item_index USING fts4(content TEXT);
 
-CREATE TRIGGER populate_index
-AFTER INSERT ON item
+CREATE TRIGGER delete_index
+AFTER DELETE ON item
 BEGIN
-  INSERT INTO item_index (docid, content)
-  VALUES (new.id, new.className);
-END;
-
-CREATE TRIGGER update_index
-AFTER UPDATE ON item
-BEGIN
-  UPDATE item_index
-  SET content = new.className
-  WHERE docid = new.id;
-END;
+  DELETE FROM item_index
+  WHERE docid = old.id;
+END
+;
 
-insertItem:
-INSERT OR FAIL INTO item(packageName, className, deprecated, link) VALUES (?, ?, ?, ?)
+insertItemIndex:
+INSERT INTO item_index (docid, content)
+VALUES (last_insert_rowid(), ('' || ?)) -- https://github.com/square/sqldelight/pull/863
 ;
 
-updateItem:
-UPDATE item
-SET deprecated = ?3,
-    link = ?4
-WHERE packageName = ?1
-  AND className = ?2
+insertItem:
+INSERT OR REPLACE INTO item(packageName, className, deprecated, link) VALUES (?, ?, ?, ?)
 ;
 
 count:
@@ -46,7 +36,7 @@ queryTerm:
 SELECT item.*
 FROM item_index
 JOIN item ON (docid = item.id)
-WHERE content LIKE '%' || ?1 || '%' ESCAPE '\'
+WHERE content MATCH ('' || ?1) -- https://github.com/square/sqldelight/pull/863
 ORDER BY
   -- deprecated classes are always last
   deprecated ASC,

store/src/main/sqldelight/migrations/4.sqm

@@ -0,0 +1,9 @@
+DROP TRIGGER populate_index;
+DROP TRIGGER update_index;
+
+CREATE TRIGGER delete_index
+AFTER DELETE ON item
+BEGIN
+  DELETE FROM item_index
+  WHERE docid = old.id;
+END;