Removing dependency on mono on linux. (#1036)

* Removing dependency on mono on linux.

* Should resolve running under .net471.

* Resolving review comments.

Author: scabana

lib/PuppeteerSharp.Tests/PuppeteerTests/BrowserFetcherTests.cs

@@ -2,9 +2,10 @@
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
-using PuppeteerSharp.Helpers.Linux;
+using Mono.Unix;
 using Xunit;
 using Xunit.Abstractions;
+using PuppeteerSharp.Helpers.Linux;
 
 namespace PuppeteerSharp.Tests.PuppeteerTests
 {
@@ -44,9 +45,11 @@ public async Task ShouldDownloadAndExtractLinuxBinary()
 
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                 {
+#if NETCOREAPP //don't need to run this code if we're not netcore app since net471 won't run on NIX. And UnixFileSystemInfo is not available for net471
                     Assert.Equal(
-                        BrowserFetcher.BrowserPermissionsInLinux,
-                        LinuxSysCall.GetFileMode(revisionInfo.ExecutablePath) & BrowserFetcher.BrowserPermissionsInLinux);
+                        LinuxPermissionsSetter.ExecutableFilePermissions, 
+                        UnixFileSystemInfo.GetFileSystemEntry(revisionInfo.ExecutablePath).FileAccessPermissions & LinuxPermissionsSetter.ExecutableFilePermissions);
+#endif               
                 }
                 Assert.Equal(new[] { 123456 }, browserFetcher.LocalRevisions());
                 browserFetcher.Remove(123456);

lib/PuppeteerSharp/BrowserFetcher.cs

@@ -1,13 +1,14 @@
 using System;
-using System.Linq;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using System.Net;
 using System.Net.Http;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
-using System.Net;
-using System.IO.Compression;
+using Mono.Unix;
 using PuppeteerSharp.Helpers.Linux;
 
 namespace PuppeteerSharp
@@ -34,13 +35,6 @@ public class BrowserFetcher
             {Platform.Win64, "{0}/chromium-browser-snapshots/Win_x64/{1}/{2}.zip"}
         };
 
-        internal static readonly FilePermissions BrowserPermissionsInLinux =
-            FilePermissions.S_IRWXU |
-            FilePermissions.S_IRGRP |
-            FilePermissions.S_IXGRP |
-            FilePermissions.S_IROTH |
-            FilePermissions.S_IXOTH;
-
         /// <summary>
         /// Default Chromium revision.
         /// </summary>
@@ -210,7 +204,7 @@ public async Task<RevisionInfo> DownloadAsync(int revision)
 
             if (revisionInfo != null && GetCurrentPlatform() == Platform.Linux)
             {
-                LinuxSysCall.SetPermissions(revisionInfo.ExecutablePath, BrowserPermissionsInLinux);
+                LinuxPermissionsSetter.SetExecutableFilePermissions(revisionInfo.ExecutablePath);
             }
             return revisionInfo;
         }

lib/PuppeteerSharp/Helpers/Linux/FilePermissions.cs

@@ -0,0 +1,21 @@
+using Mono.Unix;
+
+namespace PuppeteerSharp.Helpers.Linux
+{
+    internal static class LinuxPermissionsSetter
+    {
+        internal static readonly FileAccessPermissions ExecutableFilePermissions =
+            FileAccessPermissions.UserRead | FileAccessPermissions.UserWrite | FileAccessPermissions.UserExecute |
+            FileAccessPermissions.GroupRead |
+            FileAccessPermissions.GroupExecute |
+            FileAccessPermissions.OtherRead |
+            FileAccessPermissions.OtherExecute;
+
+        public static void SetExecutableFilePermissions(string revisionInfoExecutablePath)
+        {
+            var unixFileSystemInfo = UnixFileSystemInfo.GetFileSystemEntry(revisionInfoExecutablePath);
+
+            unixFileSystemInfo.FileAccessPermissions = ExecutableFilePermissions;
+        }
+    }
+}

lib/PuppeteerSharp/Helpers/Linux/LinuxPermissionsSetter.cs

@@ -7,54 +7,5 @@ internal static class LinuxSysCall
     {
         [DllImport("libc", SetLastError = true, EntryPoint = "chmod")]
         internal static extern int Chmod(string path, uint mode);
-
-        [DllImport("MonoPosixHelper", EntryPoint = "Mono_Posix_FromFilePermissions")]
-        internal static extern int FromFilePermissions(FilePermissions value, out uint rval);
-
-        [DllImport("MonoPosixHelper", EntryPoint = "helper_Mono_Posix_Stat")]
-        internal extern static int GetStats(
-            string filename,
-            bool dereference,
-            out int device,
-            out int inode,
-            out int mode,
-            out int nlinks,
-            out int uid,
-            out int gid,
-            out int rdev,
-            out long size,
-            out long blksize,
-            out long blocks,
-            out long atime,
-            out long mtime,
-            out long ctime);
-
-        internal static void SetPermissions(string path, FilePermissions filePermissions)
-        {
-            FromFilePermissions(filePermissions, out var permissions);
-            Chmod(path, permissions);
-        }
-
-        internal static FilePermissions GetFileMode(string filename)
-        {
-            GetStats(
-                filename,
-                false,
-                out var device,
-                out var inode,
-                out var mode,
-                out var nlinks,
-                out var uid,
-                out var gid,
-                out var rdev,
-                out var size,
-                out var blksize,
-                out var blocks,
-                out var atime,
-                out var mtime,
-                out var ctime);
-
-            return (FilePermissions)mode;
-        }
     }
 }

lib/PuppeteerSharp/Helpers/Linux/LinuxSysCall.cs

@@ -63,6 +63,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="2.0.2" />
+    <PackageReference Include="Mono.Posix.NETStandard" Version="1.0.0" />
     <PackageReference Include="Newtonsoft.Json" Version="10.0.3" />
     <PackageReference Include="System.Net.Http" Version="4.3.3" />
     <PackageReference Include="Microsoft.AspNetCore.WebUtilities" Version="2.0.2" />