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author | Ian Boros <ian.boros@mongodb.com> | 2019-08-07 13:33:54 -0400 |
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committer | Ian Boros <ian.boros@mongodb.com> | 2019-08-09 10:58:56 -0400 |
commit | 409f7bd2a1c277ce3f0f368e845c605a871ba750 (patch) | |
tree | fe59994a36106f0368704d0fc1048e2990423109 /src/mongo/db/query/projection_policies.h | |
parent | adb75a05a64e7d3a4afd8ae0ded6c183dbf0449f (diff) | |
download | mongo-409f7bd2a1c277ce3f0f368e845c605a871ba750.tar.gz |
SERVER-42665 move ProjectionPolicies to top-level mongo namespace
Diffstat (limited to 'src/mongo/db/query/projection_policies.h')
-rw-r--r-- | src/mongo/db/query/projection_policies.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/mongo/db/query/projection_policies.h b/src/mongo/db/query/projection_policies.h new file mode 100644 index 00000000000..c72790037ca --- /dev/null +++ b/src/mongo/db/query/projection_policies.h @@ -0,0 +1,73 @@ +/** + * Copyright (C) 2019-present MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ + +#pragma once + +namespace mongo { + +struct ProjectionPolicies { + // Allows the caller to indicate whether the projection should default to including or + // excluding the _id field in the event that the projection spec does not specify the + // desired behavior. For instance, given a projection {a: 1}, specifying 'kExcludeId' is + // equivalent to projecting {a: 1, _id: 0} while 'kIncludeId' is equivalent to the + // projection {a: 1, _id: 1}. If the user explicitly specifies a projection on _id, then + // this will override the default policy; for instance, {a: 1, _id: 0} will exclude _id for + // both 'kExcludeId' and 'kIncludeId'. + enum class DefaultIdPolicy { kIncludeId, kExcludeId }; + + // Allows the caller to specify how the projection should handle nested arrays; that is, an + // array whose immediate parent is itself an array. For example, in the case of sample + // document {a: [1, 2, [3, 4], {b: [5, 6]}]} the array [3, 4] is a nested array. The array + // [5, 6] is not, because there is an intervening object between it and its closest array + // ancestor. + enum class ArrayRecursionPolicy { kRecurseNestedArrays, kDoNotRecurseNestedArrays }; + + // Allows the caller to specify whether computed fields should be allowed within inclusion + // projections. Computed fields are implicitly prohibited by exclusion projections. + enum class ComputedFieldsPolicy { kBanComputedFields, kAllowComputedFields }; + + static const DefaultIdPolicy kDefaultIdPolicyDefault = DefaultIdPolicy::kIncludeId; + static const ArrayRecursionPolicy kArrayRecursionPolicyDefault = + ArrayRecursionPolicy::kRecurseNestedArrays; + static const ComputedFieldsPolicy kComputedFieldsPolicyDefault = + ComputedFieldsPolicy::kAllowComputedFields; + + ProjectionPolicies(DefaultIdPolicy idPolicy = kDefaultIdPolicyDefault, + ArrayRecursionPolicy arrayRecursionPolicy = kArrayRecursionPolicyDefault, + ComputedFieldsPolicy computedFieldsPolicy = kComputedFieldsPolicyDefault) + : idPolicy(idPolicy), + arrayRecursionPolicy(arrayRecursionPolicy), + computedFieldsPolicy(computedFieldsPolicy) {} + + const DefaultIdPolicy idPolicy; + const ArrayRecursionPolicy arrayRecursionPolicy; + const ComputedFieldsPolicy computedFieldsPolicy; +}; + +} // namespace mongo |