honour unbufferedIO flag

Author: timfel

graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/GraalPythonMain.java

@@ -71,6 +71,7 @@ public static void main(String[] args) {
     private boolean noSite = false;
     private boolean stdinIsInteractive = System.console() != null;
     private boolean runLLI = false;
+    private boolean unbufferedIO = false;
     private VersionAction versionAction = VersionAction.None;
     private String sulongLibraryPath = null;
     private List<String> givenArguments;
@@ -184,8 +185,7 @@ protected List<String> preprocessArguments(List<String> givenArgs, Map<String, S
                     inputArgs.remove("-compile-truffle-immediately");
                     break;
                 case "-u":
-                    // TODO we currently don't support this option, but needs to be consumed
-                    // due pip/wheel installer.
+                    unbufferedIO = true;
                     break;
                 default:
                     if (!arg.startsWith("-")) {
@@ -340,6 +340,7 @@ protected void launch(Builder contextBuilder) {
             inspectFlag = inspectFlag || System.getenv("PYTHONINSPECT") != null;
             noUserSite = noUserSite || System.getenv("PYTHONNOUSERSITE") != null;
             verboseFlag = verboseFlag || System.getenv("PYTHONVERBOSE") != null;
+            unbufferedIO = unbufferedIO || System.getenv("PYTHONUNBUFFERED") != null;
         }
 
         // The unlikely separator is used because options need to be strings. See
@@ -359,6 +360,7 @@ protected void launch(Builder contextBuilder) {
         contextBuilder.option("python.NoUserSiteFlag", Boolean.toString(noUserSite));
         contextBuilder.option("python.NoSiteFlag", Boolean.toString(noSite));
         contextBuilder.option("python.IgnoreEnvironmentFlag", Boolean.toString(ignoreEnv));
+        contextBuilder.option("python.UnbufferedIO", Boolean.toString(unbufferedIO));
 
         sulongLibraryPath = System.getenv("SULONG_LIBRARY_PATH");
         if (sulongLibraryPath != null) {
@@ -513,8 +515,7 @@ protected void printHelp(OptionCategory maxCategory) {
                         "-S     : don't imply 'import site' on initialization\n" +
                         // "-t : issue warnings about inconsistent tab usage (-tt: issue errors)\n"
                         // +
-                        // "-u : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x\n" +
-                        // " see man page for details on internal buffering relating to '-u'\n" +
+                        "-u     : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x\n" +
                         "-v     : verbose (trace import statements); also PYTHONVERBOSE=x\n" +
                         "         can be supplied multiple times to increase verbosity\n" +
                         "-V     : print the Python version number and exit (also --version)\n" +

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SysModuleBuiltins.java

@@ -177,6 +177,7 @@ public void postInitialize(PythonCore core) {
         sys.setAttribute("graal_python_stdlib_home", PythonOptions.getOption(context, PythonOptions.StdLibHome));
         sys.setAttribute("graal_python_opaque_filesystem", PythonOptions.getOption(context, PythonOptions.OpaqueFilesystem));
         sys.setAttribute("graal_python_opaque_filesystem_prefix", PythonOptions.getOption(context, PythonOptions.OpaqueFilesystemPrefixes));
+        sys.setAttribute("graal_python_unbuffered_io", PythonOptions.getOption(context, PythonOptions.UnbufferedIO));
         sys.setAttribute("__flags__", core.factory().createTuple(new Object[]{
                         false, // bytes_warning
                         !PythonOptions.getFlag(context, PythonOptions.PythonOptimizeFlag), // debug

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

@@ -84,6 +84,9 @@ private PythonOptions() {
     @Option(category = OptionCategory.USER, help = "Equivalent to the Python -v flag. Turn on verbose mode.") //
     public static final OptionKey<Boolean> VerboseFlag = new OptionKey<>(false);
 
+    @Option(category = OptionCategory.USER, help = "Equivalent to the Python -u flag. Force stdout and stderr to be unbuffered.") //
+    public static final OptionKey<Boolean> UnbufferedIO = new OptionKey<>(false);
+
     @Option(category = OptionCategory.DEBUG, help = "Expose internal sources as normal sources, so they will show up in the debugger and stacks") //
     public static final OptionKey<Boolean> ExposeInternalSources = new OptionKey<>(false);
 

graalpython/lib-graalpython/__builtins_patches__.py

@@ -80,12 +80,13 @@ def open(*args, **kwargs):
 sys.stdin = _pyio.TextIOWrapper(_pyio.BufferedReader(sys.stdin), encoding="utf-8", line_buffering=True)
 sys.stdin.mode = "r"
 sys.__stdin__ = sys.stdin
-sys.stdout = _pyio.TextIOWrapper(_pyio.BufferedWriter(sys.stdout), encoding="utf-8", line_buffering=True)
-sys.stdout.mode = "w"
-sys.__stdout__ = sys.stdout
-sys.stderr = _pyio.TextIOWrapper(_pyio.BufferedWriter(sys.stderr), encoding="utf-8", line_buffering=True)
-sys.stderr.mode = "w"
-sys.__stderr__ = sys.stderr
+if not sys.graal_python_unbuffered_io:
+    sys.stdout = _pyio.TextIOWrapper(_pyio.BufferedWriter(sys.stdout), encoding="utf-8", line_buffering=True)
+    sys.stdout.mode = "w"
+    sys.__stdout__ = sys.stdout
+    sys.stderr = _pyio.TextIOWrapper(_pyio.BufferedWriter(sys.stderr), encoding="utf-8", line_buffering=True)
+    sys.stderr.mode = "w"
+    sys.__stderr__ = sys.stderr
 
 
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