Support for exempting native libraries from JNI preload (#10787)

Fixes: #10617
Context: cba39dc

cba39dc introduced support for preloading of JNI native libraries at
application startup.  However, it appears that in some scenarios this
behavior isn't desired.

This PR introduces a mechanism which allows exempting some or all (with
exception of the BCL libraries) libraries from the preload mechanism.

In order to not preload any JNI libraries it's now possible to set the
`$(AndroidIgnoreAllJniPreload)` MSBuild property to `true`.

It is also possible to exempt individual libraries from preload by
adding their name to the `AndroidNativeLibraryNoJniPreload` MSBuild
item group, for instance:

    
      
    

Author: grendello

Documentation/docs-mobile/building-apps/build-items.md

@@ -33,7 +33,7 @@ The following MSBuild metadata are required:
 - `%(JavaArtifact)`: The group and artifact id of the Java library matching the specifed POM
   file in the form `{GroupId}:{ArtifactId}`.
 - `%(JavaVersion)`: The version of the Java library matching the specified POM file.
-  
+
 See the [Java Dependency Resolution documentation](../features/maven/java-dependency-verification.md)
 for more details.
 
@@ -279,9 +279,9 @@ installing app bundles.
 
 ## AndroidMavenLibrary
 
-`` allows a Maven artifact to be specified which will 
-automatically be downloaded and added to a .NET for Android binding project. 
-This can be useful to simplify maintenance of .NET for Android bindings for artifacts 
+`` allows a Maven artifact to be specified which will
+automatically be downloaded and added to a .NET for Android binding project.
+This can be useful to simplify maintenance of .NET for Android bindings for artifacts
 hosted in Maven.
 
 ```xml
@@ -336,6 +336,20 @@ used to specify the ABI that the library targets. Thus, if you add
 ItemGroup>
 ```
 
+## AndroidNativeLibraryNoJniPreload
+
+Every native library included in this item group will be exempt from the
+JNI library preload mechanism. By default, all such libraries will be loaded
+by the runtime early during application startup in order to assure their
+proper initialization. However, in some cases it might not be the desired
+behavior and this item group allows exclusion of libraries from this process
+on individual basis.
+
+Some framework libraries which must be loaded at application startup will not
+be affected if included in this item group.
+
+See also [`$(AndroidIgnoreAllJniPreload)`](build-properties.md#androidignorealljnipreload)
+
 ## AndroidPackagingOptionsExclude
 
 A set of file glob compatible items which will allow for items to be

Documentation/docs-mobile/building-apps/build-properties.md

@@ -689,6 +689,20 @@ The most common values for this property are:
 > [`@(AndroidEnvironment)`](build-items.md#androidenvironment)
 > will take precedence.
 
+## AndroidIgnoreAllJniPreload
+
+A boolean value which, if set to `true`, exempts all the native JNI libraries
+from being preloaded at application startup.  By default, all such libraries
+will be loaded by the runtime early during application startup in order to
+assure their proper initialization. However, in some cases it might not be the
+desired behavior and this property allows to effectively disable this behavior.
+
+Some framework libraries which must be loaded at application startup will not
+be affected by this property.
+
+See also [`@(AndroidNativeLibraryNoJniPreload)`](build-items.md#androidnativelibrarynojnipreload)
+for a more fine-grained way to exempt libraries from the preload mechanism.
+
 ## AndroidIncludeWrapSh
 
 A boolean value that indicates whether the Android wrapper script

build-tools/xaprepare/xaprepare/Application/KnownProperties.cs

@@ -56,6 +56,7 @@ static class KnownProperties
 		public const string PkgXamarin_LibZipSharp              = "PkgXamarin_LibZipSharp";
 		public const string ProductVersion                      = "ProductVersion";
 		public const string RuntimeRedistDirName                = "_RuntimeRedistDirName";
+		public const string TestOutputDirectory                 = "TestOutputDirectory";
 		public const string XABuildToolsFolder                  = "XABuildToolsFolder";
 		public const string XABuildToolsVersion                 = "XABuildToolsVersion";
 		public const string XABuildToolsPackagePrefixMacOS      = "XABuildToolsPackagePrefixMacOS";

build-tools/xaprepare/xaprepare/Application/Properties.Defaults.cs.in

@@ -60,6 +60,7 @@ namespace Xamarin.Android.Prepare
 			properties.Add (KnownProperties.PkgXamarin_LibZipSharp,              StripQuotes (@"@PkgXamarin_LibZipSharp@"));
 			properties.Add (KnownProperties.ProductVersion,                      StripQuotes ("@ProductVersion@"));
 			properties.Add (KnownProperties.RuntimeRedistDirName,                StripQuotes ("@_RuntimeRedistDirName@"));
+			properties.Add (KnownProperties.TestOutputDirectory,                 StripQuotes (@"@TestOutputDirectory@"));
 			properties.Add (KnownProperties.XABuildToolsFolder,                  StripQuotes (@"@XABuildToolsFolder@"));
 			properties.Add (KnownProperties.XABuildToolsVersion,                 StripQuotes ("@XABuildToolsVersion@"));
 			properties.Add (KnownProperties.XABuildToolsPackagePrefixMacOS,      StripQuotes ("@XABuildToolsPackagePrefixMacOS@"));

build-tools/xaprepare/xaprepare/Steps/Step_GenerateFiles.cs

@@ -127,6 +127,7 @@ GeneratedFile GetCmakePresetsCommon (Context context, string sourcesDir)
 				{ "@NDK_ARM64_V8A_NONMONO_API_NET@", BuildAndroidPlatforms.NdkMinimumNonMonoAPI },
 				{ "@NDK_X86_64_NONMONO_API_NET@",    BuildAndroidPlatforms.NdkMinimumNonMonoAPI },
 				{ "@XA_BUILD_CONFIGURATION@",    context.Configuration },
+				{ "@XA_TEST_OUTPUT_DIR@", Utilities.EscapePathSeparators (props.GetRequiredValue (KnownProperties.TestOutputDirectory)) },
 			};
 
 			return new GeneratedPlaceholdersFile (

build-tools/xaprepare/xaprepare/xaprepare.targets

@@ -93,6 +93,7 @@
       <Replacement Include="@PkgXamarin_LibZipSharp@=$(PkgXamarin_LibZipSharp)" />
       <Replacement Include="@ProductVersion@=$(ProductVersion)" />
       <Replacement Include="@_RuntimeRedistDirName@=$(_RuntimeRedistDirName)" />
+      <Replacement Include="@TestOutputDirectory@=$(TestOutputDirectory)" />
       <Replacement Include="@XABuildToolsFolder@=$(XABuildToolsFolder)" />
       <Replacement Include="@XABuildToolsVersion@=$(XABuildToolsVersion)" />
       <Replacement Include="@XABuildToolsPackagePrefixMacOS@=$(XABuildToolsPackagePrefixMacOS)" />

src/Xamarin.Android.Build.Tasks/Tasks/GenerateNativeApplicationConfigSources.cs

@@ -28,6 +28,8 @@ public class GenerateNativeApplicationConfigSources : AndroidTask
 		public ITaskItem[] ResolvedAssemblies { get; set; } = [];
 
 		public ITaskItem[]? NativeLibraries { get; set; }
+		public ITaskItem[]? NativeLibrariesNoJniPreload { get; set; }
+		public ITaskItem[]? NativeLibrariesAlwaysJniPreload { get; set; }
 
 		public ITaskItem[]? MonoComponents { get; set; }
 
@@ -253,6 +255,8 @@ public override bool RunTask ()
 					NumberOfAssembliesInApk = assemblyCount,
 					BundledAssemblyNameWidth = assemblyNameWidth,
 					NativeLibraries = uniqueNativeLibraries,
+					NativeLibrariesNoJniPreload = NativeLibrariesNoJniPreload,
+					NativeLibrarysAlwaysJniPreload = NativeLibrariesAlwaysJniPreload,
 					AndroidRuntimeJNIEnvToken = android_runtime_jnienv_class_token,
 					JNIEnvInitializeToken = jnienv_initialize_method_token,
 					JNIEnvRegisterJniNativesToken = jnienv_registerjninatives_method_token,
@@ -279,6 +283,8 @@ public override bool RunTask ()
 					BundledAssemblyNameWidth = assemblyNameWidth,
 					MonoComponents = (MonoComponent)monoComponents,
 					NativeLibraries = uniqueNativeLibraries,
+					NativeLibrariesNoJniPreload = NativeLibrariesNoJniPreload,
+					NativeLibrarysAlwaysJniPreload = NativeLibrariesAlwaysJniPreload,
 					HaveAssemblyStore = UseAssemblyStore,
 					AndroidRuntimeJNIEnvToken = android_runtime_jnienv_class_token,
 					JNIEnvInitializeToken = jnienv_initialize_method_token,