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[Java.Interop] Allow JniRuntime init from JavaVM* and JNIEnv* #1158

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jonpryor merged 2 commits into from
Nov 9, 2023
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[Java.Interop] Allow JniRuntime init from JavaVM* and JNIEnv* #1158

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fc6f679
[Java.Interop] Allow JniRuntime init from JavaVM* and JNIEnv*
jonpryor Nov 9, 2023
d4ea4b3
Update JreRuntime.cs
jonpryor Nov 9, 2023
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31 changes: 28 additions & 3 deletions src/Java.Interop/Java.Interop/JniRuntime.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,8 +165,8 @@ protected JniRuntime (CreationOptions options)
{
if (options == null)
throw new ArgumentNullException (nameof (options));
if (options.InvocationPointer == IntPtr.Zero)
throw new ArgumentException ("options.InvocationPointer is null", nameof (options));
if (options.InvocationPointer == IntPtr.Zero && options.EnvironmentPointer == IntPtr.Zero)
throw new ArgumentException ("Need either options.InvocationPointer or options.EnvironmentPointer!", nameof (options));

TrackIDs = options.TrackIDs;
DestroyRuntimeOnDispose = options.DestroyRuntimeOnDispose;
Expand All @@ -175,7 +175,12 @@ protected JniRuntime (CreationOptions options)
NewObjectRequired = options.NewObjectRequired;

JniVersion = options.JniVersion;
InvocationPointer = options.InvocationPointer;

if (options.InvocationPointer == IntPtr.Zero && options.EnvironmentPointer != IntPtr.Zero) {
InvocationPointer = GetInvocationPointerFromEnvironmentPointer (options.EnvironmentPointer);
} else {
InvocationPointer = options.InvocationPointer;
}
Invoker = CreateInvoker (InvocationPointer);

SetValueManager (options);
Expand Down Expand Up @@ -230,6 +235,26 @@ protected JniRuntime (CreationOptions options)
#endif // !XA_JI_EXCLUDE
}

static unsafe IntPtr GetInvocationPointerFromEnvironmentPointer (IntPtr envp)
{
IntPtr vm = IntPtr.Zero;
#if FEATURE_JNIENVIRONMENT_JI_FUNCTION_POINTERS
if (JniNativeMethods.GetJavaVM (envp, &vm) is int r &&
r != JNI_OK) {
throw new InvalidOperationException ($"Could not obtain JavaVM* from JNIEnv*; JNIEnv::GetJavaVM() returned {r}!");
}
#elif FEATURE_JNIENVIRONMENT_JI_PINVOKES
if (NativeMethods.java_interop_jnienv_get_java_vm (envp, out vm) is int r &&
r != JNI_OK) {
throw new InvalidOperationException ($"Could not obtain JavaVM* from JNIEnv*; JNIEnv::GetJavaVM() returned {r}!");
}
#else // !FEATURE_JNIENVIRONMENT_JI_FUNCTION_POINTERS && !FEATURE_JNIENVIRONMENT_JI_PINVOKES
throw new NotSupportedException ("Cannot obtain JavaVM* from JNIEnv*! " +
"Rebuild with FEATURE_JNIENVIRONMENT_JI_FUNCTION_POINTERS or FEATURE_JNIENVIRONMENT_JI_PINVOKES set!");
#endif // !FEATURE_JNIENVIRONMENT_JI_FUNCTION_POINTERS && !FEATURE_JNIENVIRONMENT_JI_PINVOKES
return vm;
}

T SetRuntime<T> (T value)
where T : class, ISetRuntime
{
Expand Down
22 changes: 15 additions & 7 deletions src/Java.Runtime.Environment/Java.Interop/JreRuntime.cs
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Expand Up @@ -39,11 +39,7 @@ public class JreRuntimeOptions : JniRuntime.CreationOptions {
public JreRuntimeOptions ()
{
JniVersion = JniVersion.v1_2;
ClassPath = new Collection<string> () {
Path.Combine (
Path.GetDirectoryName (typeof (JreRuntimeOptions).Assembly.Location) ?? throw new NotSupportedException (),
"java-interop.jar"),
};
ClassPath = new Collection<string> ();

@jonathanpeppers jonathanpeppers Nov 9, 2023

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What is Collection<string>? I've never heard of this? It would be an API break to change it, so probably can't be a List<string>.

@jonpryor jonpryor Nov 9, 2023

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Collection<T>. It's existed since .NET Framework 2.0, and is the recommended collection type in the .NET Framework Design Guidelines:

✔️ DO use Collection or a subclass of Collection<T> for properties or return values representing read/write collections.

This isn't an API break because the type hasn't changed at all, and -- again -- Collection<T> is in fact the preferred collection type here.

@jonathanpeppers jonathanpeppers Nov 9, 2023

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TIL, List vs Collection: https://stackoverflow.com/a/271842

@jonpryor jonpryor Nov 9, 2023

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Additionally, we've never "shipped" Java.Runtime.Environment.dll, so I'm fine witih making API breaks here if warranted.

}

public JreRuntimeOptions AddOption (string option)
Expand Down Expand Up @@ -80,7 +76,9 @@ static unsafe JreRuntimeOptions CreateJreVM (JreRuntimeOptions builder)
{
if (builder == null)
throw new ArgumentNullException ("builder");
if (string.IsNullOrEmpty (builder.JvmLibraryPath))
if (builder.InvocationPointer == IntPtr.Zero &&
builder.EnvironmentPointer == IntPtr.Zero &&
string.IsNullOrEmpty (builder.JvmLibraryPath))
throw new InvalidOperationException ($"Member `{nameof (JreRuntimeOptions)}.{nameof (JreRuntimeOptions.JvmLibraryPath)}` must be set.");

builder.LibraryHandler = JvmLibraryHandler.Create ();
Expand All @@ -99,11 +97,21 @@ static unsafe JreRuntimeOptions CreateJreVM (JreRuntimeOptions builder)
builder.ObjectReferenceManager = builder.ObjectReferenceManager ?? new ManagedObjectReferenceManager (builder.JniGlobalReferenceLogWriter, builder.JniLocalReferenceLogWriter);
}

if (builder.InvocationPointer != IntPtr.Zero)
if (builder.InvocationPointer != IntPtr.Zero || builder.EnvironmentPointer != IntPtr.Zero)
return builder;

builder.LibraryHandler.LoadJvmLibrary (builder.JvmLibraryPath!);

if (!builder.ClassPath.Any (p => p.EndsWith ("java-interop.jar", StringComparison.OrdinalIgnoreCase))) {
var loc = typeof (JreRuntimeOptions).Assembly.Location;
var dir = string.IsNullOrEmpty (loc) ? null : Path.GetDirectoryName (loc);
var jij = string.IsNullOrEmpty (dir) ? null : Path.Combine (dir, "java-interop.jar");
if (!File.Exists (jij)) {
throw new FileNotFoundException ($"`java-interop.jar` is required. Please add to `JreRuntimeOptions.ClassPath`. Tried to find it in `{jij}`.");
}
builder.ClassPath.Add (jij);
}

var args = new JavaVMInitArgs () {
version = builder.JniVersion,
nOptions = builder.Options.Count + 1,
Expand Down
19 changes: 19 additions & 0 deletions tests/Java.Interop-Tests/Java.Interop/JniRuntimeTest.cs
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Expand Up @@ -36,6 +36,25 @@ public void JDK_OnlySupportsOneVM ()
Assert.Fail ("Expected NotSupportedException; got: {0}", e);
}
}

[Test]
public void UseInvocationPointerOnNewThread ()
Comment on lines +40 to +41

@jonathanpeppers jonathanpeppers Nov 9, 2023

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This file is old, but could we start adding new tests with the pattern:

public async Task UseInvocationPointerOnNewThread ()
{
    await Task.Run(() => ...);
}

@jonpryor jonpryor Nov 9, 2023

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@jonathanpeppers: what's the benefit to using the Task-based version? Other than ability to use async/await?

@jonathanpeppers jonathanpeppers Nov 9, 2023

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I cringe when I see Thread.Join() that is the only reason, lol.

{
var InvocationPointer = JniRuntime.CurrentRuntime.InvocationPointer;

var t = new Thread (() => {
try {
var second = new JreRuntimeOptions () {
InvocationPointer = InvocationPointer,
}.CreateJreVM ();
}
catch (Exception e) {
Assert.Fail ("Expected no exception, got: {0}", e);
}
});
t.Start ();
t.Join ();
}
#endif // !__ANDROID__

[Test]
Expand Down