add constant value encoding

Author: rahul2393

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/KeyRecipe.java

@@ -68,8 +68,17 @@ private static final class Part {
     private final com.google.spanner.v1.KeyRecipe.Part.NullOrder nullOrder; // if kind == VALUE
     private final String identifier; // if kind == VALUE
     private final List<Integer> structIdentifiers; // if kind == VALUE
+    private final Value constantValue; // if kind == VALUE and value is set
     private final boolean random; // if kind == VALUE and random: true
 
+    private Value constantValue() {
+      return constantValue;
+    }
+
+    private boolean hasConstantValue() {
+      return constantValue != null;
+    }
+
     private Part(
         Kind kind,
         int tag,
@@ -78,6 +87,7 @@ private Part(
         com.google.spanner.v1.KeyRecipe.Part.NullOrder nullOrder,
         String identifier,
         List<Integer> structIdentifiers,
+        Value constantValue,
         boolean random) {
       this.kind = kind;
       this.tag = tag;
@@ -86,10 +96,14 @@ private Part(
       this.nullOrder = nullOrder;
       this.identifier = identifier;
       this.structIdentifiers = structIdentifiers;
+      this.constantValue = constantValue;
       this.random = random;
     }
 
     private ResolvedValue resolveValue(BiFunction<Integer, String, Value> valueFinder, int index) {
+      if (hasConstantValue()) {
+        return ResolvedValue.ofValue(constantValue());
+      }
       Value value = valueFinder.apply(index, identifier == null ? "" : identifier);
       if (value == null) {
         return ResolvedValue.missing();
@@ -112,36 +126,38 @@ private ResolvedValue resolveValue(BiFunction<Integer, String, Value> valueFinde
     }
 
     private boolean shouldConsumeValueIndex() {
-      return !random;
+      return !hasConstantValue() && !random;
     }
 
     static Part fromProto(com.google.spanner.v1.KeyRecipe.Part partProto) {
       if (partProto.getTag() != 0) {
         if (partProto.getTag() < 0) {
-          return new Part(Kind.INVALID, 0, null, null, null, null, null, false);
+          return new Part(Kind.INVALID, 0, null, null, null, null, null, null, false);
         }
-        return new Part(Kind.TAG, partProto.getTag(), null, null, null, null, null, false);
+        return new Part(Kind.TAG, partProto.getTag(), null, null, null, null, null, null, false);
       }
       if (!partProto.hasType()) {
-        return new Part(Kind.INVALID, 0, null, null, null, null, null, false);
+        return new Part(Kind.INVALID, 0, null, null, null, null, null, null, false);
       }
       if (partProto.getOrder() != com.google.spanner.v1.KeyRecipe.Part.Order.ASCENDING
           && partProto.getOrder() != com.google.spanner.v1.KeyRecipe.Part.Order.DESCENDING) {
-        return new Part(Kind.INVALID, 0, null, null, null, null, null, false);
+        return new Part(Kind.INVALID, 0, null, null, null, null, null, null, false);
       }
       if (partProto.getNullOrder() != com.google.spanner.v1.KeyRecipe.Part.NullOrder.NULLS_FIRST
           && partProto.getNullOrder() != com.google.spanner.v1.KeyRecipe.Part.NullOrder.NULLS_LAST
           && partProto.getNullOrder() != com.google.spanner.v1.KeyRecipe.Part.NullOrder.NOT_NULL) {
-        return new Part(Kind.INVALID, 0, null, null, null, null, null, false);
+        return new Part(Kind.INVALID, 0, null, null, null, null, null, null, false);
       }
       if (partProto.hasRandom()
           && partProto.getType().getCode() != com.google.spanner.v1.TypeCode.INT64) {
-        return new Part(Kind.INVALID, 0, null, null, null, null, null, false);
+        return new Part(Kind.INVALID, 0, null, null, null, null, null, null, false);
       }
 
       String identifier = partProto.hasIdentifier() ? partProto.getIdentifier() : null;
       List<Integer> structIdentifiers = new ArrayList<>(partProto.getStructIdentifiersList());
 
+      Value constantValue = partProto.hasValue() ? partProto.getValue() : null;
+
       return new Part(
           Kind.VALUE,
           0,
@@ -150,6 +166,7 @@ static Part fromProto(com.google.spanner.v1.KeyRecipe.Part partProto) {
           partProto.getNullOrder(),
           identifier,
           structIdentifiers,
+          constantValue,
           partProto.hasRandom());
     }
   }

google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/KeyRecipeTest.java

@@ -58,6 +58,24 @@ public void queryParamsUsesStructIdentifiers() throws Exception {
     assertTrue(target.limit.isEmpty());
   }
 
+  @Test
+  public void queryParamsUsesConstantValue() throws Exception {
+    com.google.spanner.v1.KeyRecipe recipeProto =
+        createRecipe(
+            "part { tag: 1 }\n"
+                + "part {\n"
+                + "  order: ASCENDING\n"
+                + "  null_order: NULLS_FIRST\n"
+                + "  type { code: STRING }\n"
+                + "  value { string_value: \"const\" }\n"
+                + "}\n");
+
+    KeyRecipe recipe = KeyRecipe.create(recipeProto);
+    TargetRange target = recipe.queryParamsToTargetRange(Struct.getDefaultInstance());
+    assertEquals(expectedKey("const"), target.start);
+    assertTrue(target.limit.isEmpty());
+  }
+
   private static com.google.spanner.v1.KeyRecipe createRecipe(String text)
       throws TextFormat.ParseException {
     com.google.spanner.v1.KeyRecipe.Builder builder = com.google.spanner.v1.KeyRecipe.newBuilder();

google-cloud-spanner/src/test/resources/finder_test.textproto

@@ -4560,8 +4560,7 @@ test_case {
       operation_uid: 1
       database_id: 1099549376513
       schema_generation: "\001\001"
-      key: "A\206\310\002"
-      limit_key: "A\206\310\003"
+      key: "A\206\310\002\234\2310\000x"
     }
   }
   event {
@@ -5327,8 +5326,7 @@ test_case {
       operation_uid: 1
       database_id: 1099548327937
       schema_generation: "\001\001"
-      key: "A\206\310\002"
-      limit_key: "A\206\310\003"
+      key: "A\206\310\002\234\2310\000x"
     }
   }
   event {
@@ -8751,8 +8749,7 @@ test_case {
       operation_uid: 1
       database_id: 1099550425089
       schema_generation: "\001\001"
-      key: "A\206\300\002"
-      limit_key: "A\206\300\003"
+      key: "A\206\300\002\221\000"
     }
   }
   event {
@@ -10079,5 +10076,3 @@ test_case {
     }
   }
 }
-
-