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/*
* Copyright 2018 Google
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_MODEL_PRECONDITION_H_
#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_MODEL_PRECONDITION_H_
#include <utility>
#if defined(__OBJC__)
#import "FIRTimestamp.h"
#import "Firestore/Source/Model/FSTDocument.h"
#include "Firestore/core/include/firebase/firestore/timestamp.h"
#endif // defined(__OBJC__)
#include "Firestore/core/src/firebase/firestore/model/maybe_document.h"
#include "Firestore/core/src/firebase/firestore/model/snapshot_version.h"
#include "Firestore/core/src/firebase/firestore/util/hard_assert.h"
namespace firebase {
namespace firestore {
namespace model {
/**
* Encodes a precondition for a mutation. This follows the model that the
* backend accepts with the special case of an explicit "empty" precondition
* (meaning no precondition).
*/
class Precondition {
public:
enum class Type {
None,
Exists,
UpdateTime,
};
/** Creates a new Precondition with an exists flag. */
static Precondition Exists(bool exists);
/** Creates a new Precondition based on a time the document exists at. */
static Precondition UpdateTime(SnapshotVersion update_time);
/** Returns a precondition representing no precondition. */
static Precondition None();
/**
* Returns true if the precondition is valid for the given document (and the
* document is available).
*/
bool IsValidFor(const MaybeDocument& maybe_doc) const;
/** Returns whether this Precondition represents no precondition. */
bool IsNone() const {
return type_ == Type::None;
}
Type type() const {
return type_;
}
const SnapshotVersion& update_time() const {
return update_time_;
}
bool operator==(const Precondition& other) const {
return type_ == other.type_ && update_time_ == other.update_time_ &&
exists_ == other.exists_;
}
#if defined(__OBJC__)
// Objective-C requires a default constructor.
Precondition()
: type_(Type::None),
update_time_(SnapshotVersion::None()),
exists_(false) {
}
// MaybeDocument is not fully ported yet. So we suppose this addition helper.
bool IsValidFor(FSTMaybeDocument* maybe_doc) const {
switch (type_) {
case Type::UpdateTime:
return [maybe_doc isKindOfClass:[FSTDocument class]] &&
firebase::firestore::model::SnapshotVersion(maybe_doc.version) ==
update_time_;
case Type::Exists:
if (exists_) {
return [maybe_doc isKindOfClass:[FSTDocument class]];
} else {
return maybe_doc == nil ||
[maybe_doc isKindOfClass:[FSTDeletedDocument class]];
}
case Type::None:
return true;
}
UNREACHABLE();
}
// For Objective-C++ hash; to be removed after migration.
// Do NOT use in C++ code.
NSUInteger Hash() const {
NSUInteger hash = std::hash<Timestamp>()(update_time_.timestamp());
hash = hash * 31 + exists_;
hash = hash * 31 + static_cast<NSUInteger>(type_);
return hash;
}
NSString* description() const {
switch (type_) {
case Type::None:
return @"<Precondition <none>>";
case Type::Exists:
if (exists_) {
return @"<Precondition exists=yes>";
} else {
return @"<Precondition exists=no>";
}
case Type::UpdateTime:
return [NSString
stringWithFormat:@"<Precondition update_time=%s>",
update_time_.timestamp().ToString().c_str()];
}
UNREACHABLE();
}
#endif // defined(__OBJC__)
private:
Precondition(Type type, SnapshotVersion update_time, bool exists);
// The actual time of this precondition.
Type type_ = Type::None;
// For UpdateTime type, preconditions a mutation based on the last updateTime.
SnapshotVersion update_time_;
// For Exists type, preconditions a mutation based on whether the document
// exists.
bool exists_;
};
} // namespace model
} // namespace firestore
} // namespace firebase
#endif // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_MODEL_PRECONDITION_H_
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