Add CompressionModulesBackend context option to be able to prefer java impls

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/NFIBz2Support.java

@@ -153,7 +153,7 @@ public String signature() {
     @CompilerDirectives.CompilationFinal private boolean available;
 
     private NFIBz2Support(PythonContext context, NativeLibrary.NFIBackend backend, String noNativeAccessHelp) {
-        if (context.isNativeAccessAllowed()) {
+        if (context.useNativeCompressionModules()) {
             this.pythonContext = context;
             this.typedNativeLib = NativeLibrary.create(PythonContext.getSupportLibName(SUPPORTING_NATIVE_LIB_NAME), Bz2NativeFunctions.values(),
                             backend, noNativeAccessHelp, false);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/NFILZMASupport.java

@@ -293,7 +293,7 @@ public String signature() {
     @CompilerDirectives.CompilationFinal private boolean available;
 
     private NFILZMASupport(PythonContext context, NativeLibrary.NFIBackend backend, String noNativeAccessHelp) {
-        if (context.isNativeAccessAllowed()) {
+        if (context.useNativeCompressionModules()) {
             this.pythonContext = context;
             this.typedNativeLib = NativeLibrary.create(PythonContext.getSupportLibName(SUPPORTING_NATIVE_LIB_NAME), LZMANativeFunctions.values(),
                             backend, noNativeAccessHelp, true);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/NFIZlibSupport.java

@@ -269,7 +269,7 @@ public String signature() {
     @CompilerDirectives.CompilationFinal private boolean available;
 
     private NFIZlibSupport(PythonContext context, NativeLibrary.NFIBackend backend, String noNativeAccessHelp) {
-        if (context.isNativeAccessAllowed()) {
+        if (context.useNativeCompressionModules()) {
             this.pythonContext = context;
             this.typedNativeLib = NativeLibrary.create(PythonContext.getSupportLibName(SUPPORTING_NATIVE_LIB_NAME),
                             ZlibNativeFunctions.values(), backend, noNativeAccessHelp, true);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonContext.java

@@ -2337,6 +2337,15 @@ public boolean isExecutableAccessAllowed() {
         return getEnv().isHostLookupAllowed() || isNativeAccessAllowed();
     }
 
+    public boolean useNativeCompressionModules() {
+        if (isNativeAccessAllowed()) {
+            TruffleString option = getLanguage().getEngineOption(PythonOptions.CompressionModulesBackend);
+            TruffleString.EqualNode eqNode = TruffleString.EqualNode.getUncached();
+            return !eqNode.execute(T_JAVA, option, TS_ENCODING);
+        }
+        return false;
+    }
+
     /**
      * Trigger any pending asynchronous actions
      */

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonOptions.java

@@ -195,12 +195,15 @@ public static void checkBytecodeDSLEnv() {
                         }
                     }));
 
-    @EngineOption @Option(category = OptionCategory.USER, help = "Choose the backend for the POSIX module.", usageSyntax = "java|native|llvm", stability = OptionStability.STABLE) //
+    @EngineOption @Option(category = OptionCategory.USER, help = "Choose the backend for the POSIX module.", usageSyntax = "java|native", stability = OptionStability.STABLE) //
     public static final OptionKey<TruffleString> PosixModuleBackend = new OptionKey<>(T_JAVA, TS_OPTION_TYPE);
 
     @EngineOption @Option(category = OptionCategory.USER, help = "Choose the backend for the Sha3 module.", usageSyntax = "java|native", stability = OptionStability.STABLE) //
     public static final OptionKey<TruffleString> Sha3ModuleBackend = new OptionKey<>(T_JAVA, TS_OPTION_TYPE);
 
+    @EngineOption @Option(category = OptionCategory.USER, help = "Choose the backend for the Zlib, Bz2, and LZMA modules.", usageSyntax = "java|native", stability = OptionStability.STABLE) //
+    public static final OptionKey<TruffleString> CompressionModulesBackend = new OptionKey<>(T_JAVA, TS_OPTION_TYPE);
+
     @Option(category = OptionCategory.USER, help = "Install default signal handlers on startup", usageSyntax = "true|false", stability = OptionStability.STABLE) //
     public static final OptionKey<Boolean> InstallSignalHandlers = new OptionKey<>(false);