From af6480e1d9be1efe3e9c25a009732dfcaa037358 Mon Sep 17 00:00:00 2001
From: Malte Rosenbjerg <rosenbjerg@users.noreply.github.com>
Date: Sat, 24 Oct 2020 22:18:16 +0200
Subject: [PATCH] Check ffmpeg/ffprobe availability #75

Former-commit-id: 0136d49edf1aa1a203d46adf1e388db6335b6d80
---
 FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs |  1 +
 FFMpegCore/FFProbe/FFProbe.cs                |  1 +
 FFMpegCore/Helpers/FFMpegHelper.cs           | 15 +++++++++++++--
 FFMpegCore/Helpers/FFProbeHelper.cs          | 17 ++++++++++++++---
 4 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs b/FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs
index e0262d4..e931eaf 100644
--- a/FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs
+++ b/FFMpegCore/FFMpeg/FFMpegArgumentProcessor.cs
@@ -126,6 +126,7 @@ await Task.WhenAll(instance.FinishedRunning().ContinueWith(t =>
         private Instance PrepareInstance(out CancellationTokenSource cancellationTokenSource)
         {
             FFMpegHelper.RootExceptionCheck(FFMpegOptions.Options.RootDirectory);
+            FFMpegHelper.VerifyFFMpegExists();
             var instance = new Instance(FFMpegOptions.Options.FFmpegBinary(), _ffMpegArguments.Text);
             instance.DataReceived += OutputData;
             cancellationTokenSource = new CancellationTokenSource();
diff --git a/FFMpegCore/FFProbe/FFProbe.cs b/FFMpegCore/FFProbe/FFProbe.cs
index 131f465..12dead6 100644
--- a/FFMpegCore/FFProbe/FFProbe.cs
+++ b/FFMpegCore/FFProbe/FFProbe.cs
@@ -87,6 +87,7 @@ private static Instance PrepareInstance(string filePath, int outputCapacity)
         {
             FFProbeHelper.RootExceptionCheck(FFMpegOptions.Options.RootDirectory);
             var ffprobe = FFMpegOptions.Options.FFProbeBinary();
+            FFProbeHelper.VerifyFFProbeExists();
             var arguments = $"-print_format json -show_format -sexagesimal -show_streams \"{filePath}\"";
             var instance = new Instance(ffprobe, arguments) {DataBufferCapacity = outputCapacity};
             return instance;
diff --git a/FFMpegCore/Helpers/FFMpegHelper.cs b/FFMpegCore/Helpers/FFMpegHelper.cs
index 8553573..f2a214e 100644
--- a/FFMpegCore/Helpers/FFMpegHelper.cs
+++ b/FFMpegCore/Helpers/FFMpegHelper.cs
@@ -2,11 +2,14 @@
 using System.Drawing;
 using System.IO;
 using FFMpegCore.Exceptions;
+using Instances;
 
 namespace FFMpegCore.Helpers
 {
     public static class FFMpegHelper
     {
+        private static bool _ffmpegVerified;
+
         public static void ConversionSizeExceptionCheck(Image image)
         {
             ConversionSizeExceptionCheck(image.Size);
@@ -32,11 +35,19 @@ public static void ExtensionExceptionCheck(string filename, string extension)
                     $"Invalid output file. File extension should be '{extension}' required.");
         }
 
-        public static void RootExceptionCheck(string root)
+        public static void RootExceptionCheck()
         {
-            if (root == null)
+            if (FFMpegOptions.Options.RootDirectory == null)
                 throw new FFMpegException(FFMpegExceptionType.Dependency,
                     "FFMpeg root is not configured in app config. Missing key 'ffmpegRoot'.");
         }
+        
+        public static void VerifyFFMpegExists()
+        {
+            if (_ffmpegVerified) return;
+            var (exitCode, _) = Instance.Finish(FFMpegOptions.Options.FFmpegBinary(), "-version");
+            _ffmpegVerified = exitCode == 0;
+            if (!_ffmpegVerified) throw new FFMpegException(FFMpegExceptionType.Operation, "ffmpeg was not found on your system");
+        }
     }
 }
diff --git a/FFMpegCore/Helpers/FFProbeHelper.cs b/FFMpegCore/Helpers/FFProbeHelper.cs
index eed1b7a..1e833e0 100644
--- a/FFMpegCore/Helpers/FFProbeHelper.cs
+++ b/FFMpegCore/Helpers/FFProbeHelper.cs
@@ -1,9 +1,12 @@
 using FFMpegCore.Exceptions;
+using Instances;
 
 namespace FFMpegCore.Helpers
 {
     public class FFProbeHelper
     {
+        private static bool _ffprobeVerified;
+
         public static int Gcd(int first, int second)
         {
             while (first != 0 && second != 0)
@@ -15,12 +18,20 @@ public static int Gcd(int first, int second)
             return first == 0 ? second : first;
         }
 
-        public static void RootExceptionCheck(string root)
+        public static void RootExceptionCheck()
         {
-            if (root == null)
+            if (FFMpegOptions.Options.RootDirectory == null)
                 throw new FFMpegException(FFMpegExceptionType.Dependency,
                     "FFProbe root is not configured in app config. Missing key 'ffmpegRoot'.");
-          
+            
+        }
+        
+        public static void VerifyFFProbeExists()
+        {
+            if (_ffprobeVerified) return;
+            var (exitCode, _) = Instance.Finish(FFMpegOptions.Options.FFProbeBinary(), "-version");
+            _ffprobeVerified = exitCode == 0;
+            if (!_ffprobeVerified) throw new FFMpegException(FFMpegExceptionType.Operation, "ffprobe was not found on your system");
         }
     }
 }