ReadViewSDK/Sources/RDReaderView/EPUBUI/ReaderController/ChapterRuntime/RDEPUBChapterDataCache.swift

import Foundation

final class RDEPUBChapterDataCache {

    private var storage: [Int: RDEPUBRuntimeChapter] = [:]

    private let lock = NSLock()

    subscript(_ spineIndex: Int) -> RDEPUBRuntimeChapter? {
        get {
            lock.lock()
            defer { lock.unlock() }
            return storage[spineIndex]
        }
        set {
            lock.lock()
            defer { lock.unlock() }
            storage[spineIndex] = newValue
        }
    }

    var storedSpineIndices: [Int] {
        lock.lock()
        defer { lock.unlock() }
        return Array(storage.keys)
    }

    func remove(spineIndex: Int) {
        lock.lock()
        defer { lock.unlock() }
        storage.removeValue(forKey: spineIndex)
    }

    func removeAll() {
        lock.lock()
        defer { lock.unlock() }
        storage.removeAll()
    }
}