222 lines
5.6 KiB
Go
222 lines
5.6 KiB
Go
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// Code generated by github.com/vektah/dataloaden, DO NOT EDIT.
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package dataloader
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import (
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"sync"
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"time"
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"github.com/photoview/photoview/api/graphql/models"
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)
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// UserFavoritesLoaderConfig captures the config to create a new UserFavoritesLoader
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type UserFavoritesLoaderConfig struct {
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// Fetch is a method that provides the data for the loader
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Fetch func(keys []*models.UserMediaData) ([]bool, []error)
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// Wait is how long wait before sending a batch
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Wait time.Duration
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// MaxBatch will limit the maximum number of keys to send in one batch, 0 = not limit
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MaxBatch int
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}
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// NewUserFavoritesLoader creates a new UserFavoritesLoader given a fetch, wait, and maxBatch
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func NewUserFavoritesLoader(config UserFavoritesLoaderConfig) *UserFavoritesLoader {
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return &UserFavoritesLoader{
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fetch: config.Fetch,
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wait: config.Wait,
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maxBatch: config.MaxBatch,
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}
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}
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// UserFavoritesLoader batches and caches requests
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type UserFavoritesLoader struct {
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// this method provides the data for the loader
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fetch func(keys []*models.UserMediaData) ([]bool, []error)
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// how long to done before sending a batch
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wait time.Duration
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// this will limit the maximum number of keys to send in one batch, 0 = no limit
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maxBatch int
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// INTERNAL
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// lazily created cache
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cache map[*models.UserMediaData]bool
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// the current batch. keys will continue to be collected until timeout is hit,
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// then everything will be sent to the fetch method and out to the listeners
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batch *userFavoritesLoaderBatch
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// mutex to prevent races
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mu sync.Mutex
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}
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type userFavoritesLoaderBatch struct {
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keys []*models.UserMediaData
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data []bool
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error []error
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closing bool
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done chan struct{}
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}
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// Load a bool by key, batching and caching will be applied automatically
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func (l *UserFavoritesLoader) Load(key *models.UserMediaData) (bool, error) {
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return l.LoadThunk(key)()
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}
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// LoadThunk returns a function that when called will block waiting for a bool.
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// This method should be used if you want one goroutine to make requests to many
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// different data loaders without blocking until the thunk is called.
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func (l *UserFavoritesLoader) LoadThunk(key *models.UserMediaData) func() (bool, error) {
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l.mu.Lock()
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if it, ok := l.cache[key]; ok {
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l.mu.Unlock()
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return func() (bool, error) {
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return it, nil
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}
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}
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if l.batch == nil {
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l.batch = &userFavoritesLoaderBatch{done: make(chan struct{})}
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}
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batch := l.batch
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pos := batch.keyIndex(l, key)
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l.mu.Unlock()
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return func() (bool, error) {
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<-batch.done
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var data bool
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if pos < len(batch.data) {
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data = batch.data[pos]
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}
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var err error
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// its convenient to be able to return a single error for everything
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if len(batch.error) == 1 {
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err = batch.error[0]
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} else if batch.error != nil {
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err = batch.error[pos]
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}
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if err == nil {
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l.mu.Lock()
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l.unsafeSet(key, data)
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l.mu.Unlock()
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}
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return data, err
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}
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}
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// LoadAll fetches many keys at once. It will be broken into appropriate sized
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// sub batches depending on how the loader is configured
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func (l *UserFavoritesLoader) LoadAll(keys []*models.UserMediaData) ([]bool, []error) {
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results := make([]func() (bool, error), len(keys))
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for i, key := range keys {
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results[i] = l.LoadThunk(key)
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}
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bools := make([]bool, len(keys))
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errors := make([]error, len(keys))
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for i, thunk := range results {
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bools[i], errors[i] = thunk()
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}
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return bools, errors
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}
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// LoadAllThunk returns a function that when called will block waiting for a bools.
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// This method should be used if you want one goroutine to make requests to many
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// different data loaders without blocking until the thunk is called.
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func (l *UserFavoritesLoader) LoadAllThunk(keys []*models.UserMediaData) func() ([]bool, []error) {
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results := make([]func() (bool, error), len(keys))
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for i, key := range keys {
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results[i] = l.LoadThunk(key)
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}
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return func() ([]bool, []error) {
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bools := make([]bool, len(keys))
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errors := make([]error, len(keys))
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for i, thunk := range results {
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bools[i], errors[i] = thunk()
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}
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return bools, errors
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}
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}
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// Prime the cache with the provided key and value. If the key already exists, no change is made
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// and false is returned.
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// (To forcefully prime the cache, clear the key first with loader.clear(key).prime(key, value).)
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func (l *UserFavoritesLoader) Prime(key *models.UserMediaData, value bool) bool {
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l.mu.Lock()
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var found bool
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if _, found = l.cache[key]; !found {
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l.unsafeSet(key, value)
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}
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l.mu.Unlock()
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return !found
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}
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// Clear the value at key from the cache, if it exists
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func (l *UserFavoritesLoader) Clear(key *models.UserMediaData) {
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l.mu.Lock()
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delete(l.cache, key)
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l.mu.Unlock()
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}
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func (l *UserFavoritesLoader) unsafeSet(key *models.UserMediaData, value bool) {
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if l.cache == nil {
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l.cache = map[*models.UserMediaData]bool{}
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}
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l.cache[key] = value
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}
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// keyIndex will return the location of the key in the batch, if its not found
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// it will add the key to the batch
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func (b *userFavoritesLoaderBatch) keyIndex(l *UserFavoritesLoader, key *models.UserMediaData) int {
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for i, existingKey := range b.keys {
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if key == existingKey {
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return i
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}
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}
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pos := len(b.keys)
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b.keys = append(b.keys, key)
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if pos == 0 {
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go b.startTimer(l)
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}
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if l.maxBatch != 0 && pos >= l.maxBatch-1 {
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if !b.closing {
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b.closing = true
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l.batch = nil
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go b.end(l)
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}
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}
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return pos
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}
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func (b *userFavoritesLoaderBatch) startTimer(l *UserFavoritesLoader) {
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time.Sleep(l.wait)
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l.mu.Lock()
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// we must have hit a batch limit and are already finalizing this batch
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if b.closing {
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l.mu.Unlock()
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return
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}
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l.batch = nil
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l.mu.Unlock()
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b.end(l)
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}
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func (b *userFavoritesLoaderBatch) end(l *UserFavoritesLoader) {
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b.data, b.error = l.fetch(b.keys)
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close(b.done)
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}
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