Allow caching fpcalc results

Probably only useful during development, when the same files are being
fingerprinted repeatedly

ConfusedPolarBear.Plugin.IntroSkipper/Configuration/PluginConfiguration.cs

@@ -16,38 +16,10 @@ public class PluginConfiguration : BasePluginConfiguration
     /// </summary>
     public PluginConfiguration()
     {
-        AnalysisResults = new Collection<Intro>();
     }
 
     /// <summary>
-    /// Save timestamps to disk.
+    /// If the output of fpcalc should be cached to the filesystem.
     /// </summary>
-    public void SaveTimestamps()
+    public bool CacheFingerprints { get; set; }
-    {
-        AnalysisResults.Clear();
-
-        foreach (var intro in Plugin.Instance!.Intros)
-        {
-            AnalysisResults.Add(intro.Value);
-        }
-
-        Plugin.Instance!.SaveConfiguration();
-    }
-
-    /// <summary>
-    /// Restore previous analysis results from disk.
-    /// </summary>
-    public void RestoreTimestamps()
-    {
-        // Since dictionaries can't be easily serialized, analysis results are stored on disk as a list.
-        foreach (var intro in AnalysisResults)
-        {
-            Plugin.Instance!.Intros[intro.EpisodeId] = intro;
-        }
-    }
-
-    /// <summary>
-    /// Previous analysis results.
-    /// </summary>
-    public Collection<Intro> AnalysisResults { get; private set; }
 }

ConfusedPolarBear.Plugin.IntroSkipper/Configuration/configPage.html

@@ -8,29 +8,17 @@
     <div id="TemplateConfigPage" data-role="page" class="page type-interior pluginConfigurationPage" data-require="emby-input,emby-button,emby-select,emby-checkbox">
         <div data-role="content">
             <div class="content-primary">
-                <form id="TemplateConfigForm">
+                <form id="FingerprintConfigForm">
-                    <div class="selectContainer">
-                        <label class="selectLabel" for="Options">Several Options</label>
-                        <select is="emby-select" id="Options" name="Options" class="emby-select-withcolor emby-select">
-                            <option id="optOneOption" value="OneOption">One Option</option>
-                            <option id="optAnotherOption" value="AnotherOption">Another Option</option>
-                        </select>
-                    </div>
-                    <div class="inputContainer">
-                        <label class="inputLabel inputLabelUnfocused" for="AnInteger">An Integer</label>
-                        <input id="AnInteger" name="AnInteger" type="number" is="emby-input" min="0" />
-                        <div class="fieldDescription">A Description</div>
-                    </div>
                     <div class="checkboxContainer checkboxContainer-withDescription">
                         <label class="emby-checkbox-label">
-                            <input id="TrueFalseSetting" name="TrueFalseCheckBox" type="checkbox" is="emby-checkbox" />
+                            <input id="CacheFingerprints" type="checkbox" is="emby-checkbox" />
-                            <span>A Checkbox</span>
+                            <span>Cache fingerprints to disk</span>
                         </label>
+
+                        <div class="fieldDescription">
+                            If checked, will store the fingerprints for all subsequently scanned files to disk.
+                            Caching fingerprints avoids having to re-run fpcalc on each file, at the expense of disk usage.
                         </div>
-                    <div class="inputContainer">
-                        <label class="inputeLabel inputLabelUnfocused" for="AString">A String</label>
-                        <input id="AString" name="AString" type="text" is="emby-input" />
-                        <div class="fieldDescription">Another Description</div>
                     </div>
                     <div>
                         <button is="emby-button" type="submit" class="raised button-submit block emby-button">
@@ -42,29 +30,23 @@
         </div>
         <script type="text/javascript">
             var TemplateConfig = {
-                pluginUniqueId: 'eb5d7894-8eef-4b36-aa6f-5d124e828ce1'
+                pluginUniqueId: 'c83d86bb-a1e0-4c35-a113-e2101cf4ee6b'
             };
 
             document.querySelector('#TemplateConfigPage')
                 .addEventListener('pageshow', function() {
                     Dashboard.showLoadingMsg();
                     ApiClient.getPluginConfiguration(TemplateConfig.pluginUniqueId).then(function (config) {
-                        document.querySelector('#Options').value = config.Options;
+                        document.querySelector('#CacheFingerprints').checked = config.CacheFingerprints;
-                        document.querySelector('#AnInteger').value = config.AnInteger;
-                        document.querySelector('#TrueFalseSetting').checked = config.TrueFalseSetting;
-                        document.querySelector('#AString').value = config.AString;
                         Dashboard.hideLoadingMsg();
                     });
                 });
 
-            document.querySelector('#TemplateConfigForm')
+            document.querySelector('#FingerprintConfigForm')
                 .addEventListener('submit', function() {
                 Dashboard.showLoadingMsg();
                 ApiClient.getPluginConfiguration(TemplateConfig.pluginUniqueId).then(function (config) {
-                    config.Options = document.querySelector('#Options').value;
+                    config.CacheFingerprints = document.querySelector('#CacheFingerprints').checked;
-                    config.AnInteger = document.querySelector('#AnInteger').value;
-                    config.TrueFalseSetting = document.querySelector('#TrueFalseSetting').checked;
-                    config.AString = document.querySelector('#AString').value;
                     ApiClient.updatePluginConfiguration(TemplateConfig.pluginUniqueId, config).then(function (result) {
                         Dashboard.processPluginConfigurationUpdateResult(result);
                     });

ConfusedPolarBear.Plugin.IntroSkipper/FPCalc.cs

@@ -3,6 +3,8 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Globalization;
+using System.IO;
+using System.Text;
 using Microsoft.Extensions.Logging;
 
 namespace ConfusedPolarBear.Plugin.IntroSkipper;
@@ -39,6 +41,13 @@ public static class FPCalc {
     /// <param name="episode">Queued episode to fingerprint.</param>
     public static ReadOnlyCollection<uint> Fingerprint(QueuedEpisode episode)
     {
+        // Try to load this episode from cache before running fpcalc.
+        if (loadCachedFingerprint(episode, out ReadOnlyCollection<uint> cachedFingerprint))
+        {
+            Logger?.LogDebug("Fingerprint cache hit on {File}", episode.Path);
+            return cachedFingerprint;
+        }
+
         Logger?.LogDebug("Fingerprinting {Duration} seconds from {File}", episode.FingerprintDuration, episode.Path);
 
         // FIXME: revisit escaping
@@ -69,9 +78,17 @@ public static class FPCalc {
             results.Add(Convert.ToUInt32(rawNumber, CultureInfo.InvariantCulture));
         }
 
+        // Try to cache this fingerprint.
+        cacheFingerprint(episode, results);
+
         return results.AsReadOnly();
     }
 
+    /// <summary>
+    /// Runs fpcalc and returns standard output.
+    /// </summary>
+    /// <param name="args">Arguments to pass to fpcalc.</param>
+    /// <param name="timeout">Timeout (in seconds) to wait for fpcalc to exit.</param>
     private static string getOutput(string args, int timeout = 60 * 1000)
     {
         var info = new ProcessStartInfo("fpcalc", args);
@@ -86,4 +103,76 @@ public static class FPCalc {
 
         return fpcalc.StandardOutput.ReadToEnd();
     }
+
+    /// <summary>
+    /// Tries to load an episode's fingerprint from cache. If caching is not enabled, calling this function is a no-op.
+    /// </summary>
+    /// <param name="episode">Episode to try to load from cache.</param>
+    /// <param name="fingerprint">ReadOnlyCollection to store the fingerprint in.</param>
+    /// <returns>true if the episode was successfully loaded from cache, false on any other error.</returns>
+    private static bool loadCachedFingerprint(QueuedEpisode episode, out ReadOnlyCollection<uint> fingerprint)
+    {
+        fingerprint = new List<uint>().AsReadOnly();
+
+        // If fingerprint caching isn't enabled, don't try to load anything.
+        if (!Plugin.Instance!.Configuration.CacheFingerprints)
+        {
+            return false;
+        }
+
+        var path = getFingerprintCachePath(episode);
+
+        // If this episode isn't cached, bail out.
+        if (!File.Exists(path))
+        {
+            return false;
+        }
+
+        // TODO: make async
+        var raw = File.ReadAllLines(path, Encoding.UTF8);
+        var result = new List<uint>();
+
+        // Read each stringified uint.
+        result.EnsureCapacity(raw.Length);
+        foreach (var rawNumber in raw)
+        {
+            result.Add(Convert.ToUInt32(rawNumber, CultureInfo.InvariantCulture));
+        }
+
+        fingerprint = result.AsReadOnly();
+        return true;
+    }
+
+    /// <summary>
+    /// Cache an episode's fingerprint to disk. If caching is not enabled, calling this function is a no-op.
+    /// </summary>
+    /// <param name="episode">Episode to store in cache.</param>
+    /// <param name="fingerprint">Fingerprint of the episode to store.</param>
+    private static void cacheFingerprint(QueuedEpisode episode, List<uint> fingerprint)
+    {
+        // Bail out if caching isn't enabled.
+        if (!Plugin.Instance!.Configuration.CacheFingerprints)
+        {
+            return;
+        }
+
+        // Stringify each data point.
+        var lines = new List<string>();
+        foreach (var number in fingerprint)
+        {
+            lines.Add(number.ToString(CultureInfo.InvariantCulture));
+        }
+
+        // Cache the episode.
+        File.WriteAllLinesAsync(getFingerprintCachePath(episode), lines, Encoding.UTF8).ConfigureAwait(false);
+    }
+
+    /// <summary>
+    /// Determines the path an episode should be cached at.
+    /// </summary>
+    /// <param name="episode">Episode.</param>
+    private static string getFingerprintCachePath(QueuedEpisode episode)
+    {
+        return Path.Join(Plugin.Instance!.FingerprintCachePath, episode.EpisodeId.ToString("N"));
+    }
 }

ConfusedPolarBear.Plugin.IntroSkipper/Plugin.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
+using System.IO;
 using ConfusedPolarBear.Plugin.IntroSkipper.Configuration;
 using MediaBrowser.Common.Configuration;
 using MediaBrowser.Common.Plugins;
@@ -14,6 +15,9 @@ namespace ConfusedPolarBear.Plugin.IntroSkipper;
 /// </summary>
 public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
 {
+    private IXmlSerializer _xmlSerializer;
+    private string _introPath;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="Plugin"/> class.
     /// </summary>
@@ -22,11 +26,69 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
     public Plugin(IApplicationPaths applicationPaths, IXmlSerializer xmlSerializer)
         : base(applicationPaths, xmlSerializer)
     {
+        _xmlSerializer = xmlSerializer;
+
+        // Create the base & cache directories (if needed).
+        FingerprintCachePath = Path.Join(applicationPaths.PluginConfigurationsPath, "intros", "cache");
+        if (!Directory.Exists(FingerprintCachePath))
+        {
+            Directory.CreateDirectory(FingerprintCachePath);
+        }
+
+        _introPath = Path.Join(applicationPaths.PluginConfigurationsPath, "intros", "intros.xml");
+
         Intros = new Dictionary<Guid, Intro>();
         AnalysisQueue = new Dictionary<Guid, List<QueuedEpisode>>();
         Instance = this;
 
-        Configuration.RestoreTimestamps();
+        RestoreTimestamps();
+    }
+
+    /// <summary>
+    /// Save timestamps to disk.
+    /// </summary>
+    public void SaveTimestamps()
+    {
+        var introList = new List<Intro>();
+
+        foreach (var intro in Plugin.Instance!.Intros)
+        {
+            introList.Add(intro.Value);
+        }
+
+        _xmlSerializer.SerializeToFile(introList, _introPath);
+    }
+
+    /// <summary>
+    /// Restore previous analysis results from disk.
+    /// </summary>
+    public void RestoreTimestamps()
+    {
+        if (!File.Exists(_introPath))
+        {
+            return;
+        }
+
+        // Since dictionaries can't be easily serialized, analysis results are stored on disk as a list.
+        var introList = (List<Intro>)_xmlSerializer.DeserializeFromFile(typeof(List<Intro>), _introPath);
+
+        foreach (var intro in introList)
+        {
+            Plugin.Instance!.Intros[intro.EpisodeId] = intro;
+        }
+    }
+
+    /// <inheritdoc />
+    public IEnumerable<PluginPageInfo> GetPages()
+    {
+        return new[]
+        {
+            new PluginPageInfo
+            {
+                Name = this.Name,
+                EmbeddedResourcePath = string.Format(CultureInfo.InvariantCulture, "{0}.Configuration.configPage.html", GetType().Namespace)
+            }
+        };
     }
 
     /// <summary>
@@ -44,6 +106,11 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
     /// </summary>
     public int TotalQueued { get; set; }
 
+    /// <summary>
+    /// Directory to cache fingerprints in.
+    /// </summary>
+    public string FingerprintCachePath { get; private set; }
+
     /// <inheritdoc />
     public override string Name => "Intro Skipper";
 
@@ -52,17 +119,4 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
 
     /// <inheritdoc />
     public static Plugin? Instance { get; private set; }
-
-    /// <inheritdoc />
-    public IEnumerable<PluginPageInfo> GetPages()
-    {
-        return new[]
-        {
-            new PluginPageInfo
-            {
-                Name = this.Name,
-                EmbeddedResourcePath = string.Format(CultureInfo.InvariantCulture, "{0}.Configuration.configPage.html", GetType().Namespace)
-            }
-        };
-    }
 }

ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/FingerprinterTask.cs

@@ -153,7 +153,7 @@ public class FingerprinterTask : IScheduledTask {
                 }
             }
 
-            Plugin.Instance!.Configuration.SaveTimestamps();
+            Plugin.Instance!.SaveTimestamps();
 
             if (cancellationToken.IsCancellationRequested)
             {