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-rw-r--r--libtransport/src/utils/suffix_strategy.h165
1 files changed, 165 insertions, 0 deletions
diff --git a/libtransport/src/utils/suffix_strategy.h b/libtransport/src/utils/suffix_strategy.h
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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