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/*
* Copyright (c) 2017-2019 Cisco and/or its affiliates.
* 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.
*/
#pragma once
#include <core/manifest_format.h>
namespace utils {
using transport::core::NextSegmentCalculationStrategy;
class SuffixStrategy {
public:
static constexpr uint32_t INVALID_SUFFIX =
std::numeric_limits<uint32_t>::max();
SuffixStrategy(NextSegmentCalculationStrategy strategy)
: suffix_stragegy_(strategy),
total_count_(0),
final_suffix_(INVALID_SUFFIX) {}
virtual ~SuffixStrategy() = default;
virtual uint32_t getNextSuffix() = 0;
virtual uint32_t getFinalSuffix() { return final_suffix_; }
virtual void setFinalSuffix(std::uint32_t final_suffix) {
if (final_suffix != INVALID_SUFFIX) {
final_suffix_ = final_suffix;
}
}
virtual uint32_t getNextManifestSuffix() = 0;
virtual uint32_t getNextContentSuffix() = 0;
virtual void reset(uint32_t offset = 0) = 0;
virtual uint32_t getManifestCapacity() = 0;
virtual void setManifestCapacity(uint32_t capacity) = 0;
virtual uint32_t getTotalCount() { return total_count_; };
NextSegmentCalculationStrategy getSuffixStrategy() {
return suffix_stragegy_;
}
protected:
inline void incrementTotalCount() { total_count_++; };
protected:
NextSegmentCalculationStrategy suffix_stragegy_;
std::uint32_t total_count_;
std::uint32_t final_suffix_;
};
class IncrementalSuffixStrategy : public SuffixStrategy {
public:
IncrementalSuffixStrategy(std::uint32_t start_offset)
: SuffixStrategy(NextSegmentCalculationStrategy::INCREMENTAL),
next_suffix_(start_offset) {}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextSuffix() override {
incrementTotalCount();
return next_suffix_++;
}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextContentSuffix() override {
return getNextSuffix();
}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextManifestSuffix() override {
return getNextSuffix();
}
uint32_t getManifestCapacity() override {
throw errors::RuntimeException(
"No manifest capacity in IncrementalSuffixStrategy.");
}
void setManifestCapacity(uint32_t capacity) override {
throw errors::RuntimeException(
"No manifest capacity in IncrementalSuffixStrategy.");
}
void reset(std::uint32_t offset = 0) override { next_suffix_ = offset; }
protected:
std::uint32_t next_suffix_;
};
class CapacityBasedSuffixStrategy : public SuffixStrategy {
public:
CapacityBasedSuffixStrategy(std::uint32_t start_offset,
std::uint32_t manifest_capacity)
: SuffixStrategy(NextSegmentCalculationStrategy::INCREMENTAL),
next_suffix_(start_offset),
segments_in_manifest_(manifest_capacity),
current_manifest_iteration_(0) {}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextSuffix() override {
incrementTotalCount();
return next_suffix_++;
}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextContentSuffix() override {
incrementTotalCount();
return next_suffix_ % segments_in_manifest_ == 0 ? next_suffix_++
: ++next_suffix_;
}
TRANSPORT_ALWAYS_INLINE std::uint32_t getNextManifestSuffix() override {
incrementTotalCount();
return (current_manifest_iteration_++) * (segments_in_manifest_ + 1);
}
TRANSPORT_ALWAYS_INLINE uint32_t getManifestCapacity() override {
return segments_in_manifest_;
}
TRANSPORT_ALWAYS_INLINE void setManifestCapacity(uint32_t capacity) override {
segments_in_manifest_ = capacity;
}
void reset(std::uint32_t offset = 0) override { next_suffix_ = offset; }
protected:
std::uint32_t next_suffix_;
std::uint32_t segments_in_manifest_;
std::uint32_t current_manifest_iteration_;
};
class SuffixStrategyFactory {
public:
static std::unique_ptr<SuffixStrategy> getSuffixStrategy(
NextSegmentCalculationStrategy strategy, uint32_t start_offset,
uint32_t manifest_capacity = 0) {
switch (strategy) {
case NextSegmentCalculationStrategy::INCREMENTAL:
return std::make_unique<IncrementalSuffixStrategy>(start_offset);
case NextSegmentCalculationStrategy::MANIFEST_CAPACITY_BASED:
return std::make_unique<CapacityBasedSuffixStrategy>(start_offset,
manifest_capacity);
default:
throw errors::RuntimeException(
"No valid NextSegmentCalculationStrategy specified.");
}
}
};
} // namespace utils
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