Sync from upstream.

Descriptions:
================
Replace refs to c lib headers w/ c++ stdlib equivalents.
================
Update IDF component of BM25F Calculator in IcingLib
================
Expose QuerySuggestions API.
================
Change the tokenizer used in QuerySuggest.
================
Add SectionWeights API to Icing.
================
Apply SectionWeights to BM25F Scoring.
================
Replaces uses of u_strTo/FromUTF32 w/ u_strTo/FromUTF8.

Bug: 152934343
Bug: 202308641
Bug: 203700301
Change-Id: Ic884a84e5ff4c9c04b2cd6dd1fce90765aa4446e

2 files changed, 61 insertions, 0 deletions

diff --git a/java/src/com/google/android/icing/IcingSearchEngine.java b/java/src/com/google/android/icing/IcingSearchEngine.java
index 1f5fb51..95e0c84 100644
--- a/java/src/com/google/android/icing/IcingSearchEngine.java
+++ b/java/src/com/google/android/icing/IcingSearchEngine.java
@@ -43,6 +43,8 @@ import com.google.android.icing.proto.SearchSpecProto;
 import com.google.android.icing.proto.SetSchemaResultProto;
 import com.google.android.icing.proto.StatusProto;
 import com.google.android.icing.proto.StorageInfoResultProto;
+import com.google.android.icing.proto.SuggestionResponse;
+import com.google.android.icing.proto.SuggestionSpecProto;
 import com.google.android.icing.proto.UsageReport;
 import com.google.protobuf.ExtensionRegistryLite;
 import com.google.protobuf.InvalidProtocolBufferException;
@@ -370,6 +372,26 @@ public class IcingSearchEngine implements Closeable {
   }
 
   @NonNull
+  public SuggestionResponse searchSuggestions(@NonNull SuggestionSpecProto suggestionSpec) {
+    byte[] suggestionResponseBytes = nativeSearchSuggestions(this, suggestionSpec.toByteArray());
+    if (suggestionResponseBytes == null) {
+      Log.e(TAG, "Received null suggestionResponseBytes from native.");
+      return SuggestionResponse.newBuilder()
+          .setStatus(StatusProto.newBuilder().setCode(StatusProto.Code.INTERNAL))
+          .build();
+    }
+
+    try {
+      return SuggestionResponse.parseFrom(suggestionResponseBytes, EXTENSION_REGISTRY_LITE);
+    } catch (InvalidProtocolBufferException e) {
+      Log.e(TAG, "Error parsing suggestionResponseBytes.", e);
+      return SuggestionResponse.newBuilder()
+          .setStatus(StatusProto.newBuilder().setCode(StatusProto.Code.INTERNAL))
+          .build();
+    }
+  }
+
+  @NonNull
   public DeleteByNamespaceResultProto deleteByNamespace(@NonNull String namespace) {
     throwIfClosed();
 
@@ -604,4 +626,7 @@ public class IcingSearchEngine implements Closeable {
   private static native byte[] nativeGetStorageInfo(IcingSearchEngine instance);
 
   private static native byte[] nativeReset(IcingSearchEngine instance);
+
+  private static native byte[] nativeSearchSuggestions(
+      IcingSearchEngine instance, byte[] suggestionSpecBytes);
 }
diff --git a/java/tests/instrumentation/src/com/google/android/icing/IcingSearchEngineTest.java b/java/tests/instrumentation/src/com/google/android/icing/IcingSearchEngineTest.java
index 0cee80c..cb28331 100644
--- a/java/tests/instrumentation/src/com/google/android/icing/IcingSearchEngineTest.java
+++ b/java/tests/instrumentation/src/com/google/android/icing/IcingSearchEngineTest.java
@@ -51,6 +51,8 @@ import com.google.android.icing.proto.StatusProto;
 import com.google.android.icing.proto.StorageInfoResultProto;
 import com.google.android.icing.proto.StringIndexingConfig;
 import com.google.android.icing.proto.StringIndexingConfig.TokenizerType;
+import com.google.android.icing.proto.SuggestionResponse;
+import com.google.android.icing.proto.SuggestionSpecProto;
 import com.google.android.icing.proto.TermMatchType;
 import com.google.android.icing.proto.UsageReport;
 import com.google.android.icing.IcingSearchEngine;
@@ -623,6 +625,40 @@ public final class IcingSearchEngineTest {
     assertThat(match).isEqualTo("𐀂𐀃");
   }
 
+  @Test
+  public void testSearchSuggestions() {
+    assertStatusOk(icingSearchEngine.initialize().getStatus());
+
+    SchemaTypeConfigProto emailTypeConfig = createEmailTypeConfig();
+    SchemaProto schema = SchemaProto.newBuilder().addTypes(emailTypeConfig).build();
+    assertThat(
+            icingSearchEngine
+                .setSchema(schema, /*ignoreErrorsAndDeleteDocuments=*/ false)
+                .getStatus()
+                .getCode())
+        .isEqualTo(StatusProto.Code.OK);
+
+    DocumentProto emailDocument1 =
+        createEmailDocument("namespace", "uri1").toBuilder()
+            .addProperties(PropertyProto.newBuilder().setName("subject").addStringValues("fo"))
+            .build();
+    DocumentProto emailDocument2 =
+        createEmailDocument("namespace", "uri2").toBuilder()
+            .addProperties(PropertyProto.newBuilder().setName("subject").addStringValues("foo"))
+            .build();
+    assertStatusOk(icingSearchEngine.put(emailDocument1).getStatus());
+    assertStatusOk(icingSearchEngine.put(emailDocument2).getStatus());
+
+    SuggestionSpecProto suggestionSpec =
+        SuggestionSpecProto.newBuilder().setPrefix("f").setNumToReturn(10).build();
+
+    SuggestionResponse response = icingSearchEngine.searchSuggestions(suggestionSpec);
+    assertStatusOk(response.getStatus());
+    assertThat(response.getSuggestionsList()).hasSize(2);
+    assertThat(response.getSuggestions(0).getQuery()).isEqualTo("foo");
+    assertThat(response.getSuggestions(1).getQuery()).isEqualTo("fo");
+  }
+
   private static void assertStatusOk(StatusProto status) {
     assertWithMessage(status.getMessage()).that(status.getCode()).isEqualTo(StatusProto.Code.OK);
   }