src.org.python.core.PrePy Maven / Gradle / Ivy
Show all versions of jython Show documentation
package org.python.core;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.security.AccessControlException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import jnr.posix.util.Platform;
/**
* This class is part of the Jython run-time system, and contains only "pre-Python" data and methods
* that may safely be used before the type system is ready. The Jython type system springs into
* existence in response to a program's first use of any {@code PyObject}, for example when creating
* the first interpreter. When preparing an application (from the command line options, say) for
* creation of the first interpreter, it useful to defer type system creation until pre-Python
* configuration is complete. See PEP 432 for further rationale.
*
* Creation of the type system may happen as a side effect of referring using (almost) any object
* from a class that statically refers to a {@code PyObject}, for example {@code Py} or
* {@code PySystemState}. The present class is intended to hold utility methods and configuration
* useful in the pre-Python phase.
*/
// Do not refer to any PyObject, Py export or PySystemState in this class.
public class PrePy {
// Logging functions are here so they may be used without starting the Jython runtime.
/** Our name-spaced root logger is "org.python". */
protected static final Logger logger = Logger.getLogger("org.python");
protected static final Logger importLogger = Logger.getLogger("org.python.import");
/** {@link Options#verbose} level indicating an error that prevents correct results. */
public static final int ERROR = -1;
/** {@link Options#verbose} level indicating an unexpected event, still working correctly. */
public static final int WARNING = 0;
/** {@link Options#verbose} level for messages that confirm correct functioning. */
public static final int MESSAGE = 1;
/** {@link Options#verbose} level providing detail during correct functioning. */
public static final int COMMENT = 2;
/** {@link Options#verbose} level providing detail in support of debugging or tracing. */
public static final int DEBUG = 3;
static final Level[] LEVELS = {//
Level.OFF, //
Level.SEVERE, // Legacy: ERROR
Level.WARNING, // Legacy: WARNING
Level.INFO, // Legacy: MESSAGE
Level.CONFIG, // Legacy: COMMENT
Level.FINE, // Legacy: DEBUG
Level.FINER, Level.FINEST, Level.ALL};
/**
* Translate from the traditional "verbosity" system to JUL Level. We allow Jython verbosity
* values beyond the conventional range, treating values <{@link #ERROR} as {@code ERROR}
* (that is {@code Level.SEVERE}) and values >{@link #DEBUG} (that is {@code Level.FINE}) as
* {@code FINER}, {@code FINEST} and {@code ALL}.
*
* @param verbosity any integer verbosity, where the runtime default {@link #MESSAGE} = 1
* @return a corresponding level where the default {@link #MESSAGE} produces {@code Level.INFO}.
*/
public static Level levelFromVerbosity(int verbosity) {
if (verbosity < ERROR) {
return Level.OFF;
} else if (verbosity >= LEVELS.length + (ERROR - 1)) {
return Level.ALL;
} else {
// Bound the index to the LEVELS array.
int index = verbosity - (ERROR - 1);
return LEVELS[index];
}
}
/**
* Translate from JUL Level to equivalent in the traditional "verbosity" system. We return
* Jython verbosity values beyond the conventional range, enough to enumerate the Java standard
* levels (e.g {@code FINER} returns 4 and {@code ALL} returns 6 ).
*
* @param level {@code java.util.logging.Level} to translate.
* @return integer verbosity, where the runtime default {@code INFO} = 1
*/
public static int verbosityFromLevel(Level level) {
/*
* Find the least verbose setting v such that events at the given level or above will be
* logged by Jython, that is, v such that levelFromVerbosity(v) is a threshold no higher
* than the given level. We allow Jython verbosity values beyond the conventional range (e.g
* level==FINER), according to the range of values in the LEVELS array.
*/
int intLevel = level.intValue();
int index = 0, v = ERROR - 1; // = OFF
while (index < LEVELS.length && LEVELS[index].intValue() > intLevel) {
assert LEVELS[index] == levelFromVerbosity(v);
index += 1;
v += 1;
}
return v;
}
/**
* Convenience function to get the effective level of a given Logger, looking up the parent
* chain. If the root logger is reached without an explicit level set, assume
* {@code Level.INFO}.
*/
private static Level getEffectiveLoggingLevel(Logger logger) {
Level level = null;
while (logger != null && (level = logger.getLevel()) == null) {
logger = logger.getParent();
}
return level != null ? level : Level.INFO;
}
/** Convenience function to get the effective level of Logger "org.python". */
public static Level getLoggingLevel() {
return getEffectiveLoggingLevel(logger);
}
/**
* Used by {@link #maybeWrite(Level, String)}, the terminus of all verbosity-based logging
* calls, to detect changes made directly to {@link Options#verbose}.
*/
private static int savedVerbosity = MESSAGE;
/**
* Set the level of the Jython logger "org.python" using the standard {@code java.util.logging}
* scale. For backward compatibility with the traditional "verbosity" system, make a
* corresponding setting of {@link Options#verbose}.
*
* @param newLevel to set
* @return previous logging level
*/
@SuppressWarnings("deprecation")
public static Level setLoggingLevel(Level newLevel) {
Level previousLevel = getLoggingLevel();
if (newLevel != previousLevel) {
try {
logger.setLevel(newLevel);
} catch (SecurityException se) {
logger.warning("A security manager prevented a change to the logging level.");
newLevel = previousLevel;
}
}
savedVerbosity = Options.verbose = verbosityFromLevel(newLevel);
return previousLevel;
}
/**
* Adjust the level of the Jython logger "org.python" using the traditional "verbosity" system:
* the bigger the number, the lower the logging threshold. This is primarily for the
* command-line Jython, where each "-v" increases the verbosity by one, on the
* {@code java.util.logging} scale.
*
* @param n increment on the scale {@code 1=INFO, 2=CONFIG, 3=FINE, ... }
*/
public static void increaseLoggingLevel(int n) {
int v = verbosityFromLevel(getLoggingLevel());
setLoggingLevel(levelFromVerbosity(v + n));
}
/**
* Ensure that the logging system threshold is adjusted to match the legacy
* {@link Options#verbose} in the event that that has changed since we last looked.
*/
@SuppressWarnings("deprecation")
private static void syncLoggingLevel() {
if (Options.verbose != savedVerbosity) {
Level level = levelFromVerbosity(savedVerbosity = Options.verbose);
setLoggingLevel(level);
}
}
/** Log a message at a specified level (if that level is not below the threshold). */
@SuppressWarnings("deprecation")
public static void maybeWrite(String type, String msg, int verbosity) {
// If the caller is using the legacy logging system they may have changed Options.verbose.
syncLoggingLevel();
if (verbosity <= Options.verbose) {
// Formulate the message in legacy style, then as a log message
logger.log(levelFromVerbosity(verbosity), "{0}: {1}", new Object[] {type, msg});
}
}
/** Submit a message to logging at the severity level ERROR. */
public static void writeError(String type, String msg) {
maybeWrite(type, msg, ERROR);
}
/** Submit a message to logging at the severity level WARNING. */
public static void writeWarning(String type, String msg) {
maybeWrite(type, msg, WARNING);
}
/** Submit a message to logging at the severity level MESSAGE. */
public static void writeMessage(String type, String msg) {
maybeWrite(type, msg, MESSAGE);
}
/** Submit a message to logging at the severity level COMMENT. */
public static void writeComment(String type, String msg) {
maybeWrite(type, msg, COMMENT);
}
/** Submit a message to logging at the severity level DEBUG. */
public static void writeDebug(String type, String msg) {
maybeWrite(type, msg, DEBUG);
}
/**
* Get the System properties if we are allowed to. Configuration values set via
* {@code -Dprop=value} to the java command will be found here. If a security manager prevents
* access, we will return a new (empty) object instead.
*
* @return {@code System} properties or a new {@code Properties} object
*/
public static Properties getSystemProperties() {
try {
return System.getProperties();
} catch (AccessControlException ace) {
return new Properties();
}
}
/**
* Get a System property if it is defined, not null, and we are allowed to access it, otherwise
* return the given default.
*
* @param key of the entry to return
* @param defaultValue to return if null or disallowed
* @return property value or given default
*/
public static String getSystemProperty(String key, String defaultValue) {
try {
String value = System.getProperty(key, null);
return value != null ? value : defaultValue;
} catch (AccessControlException ace) {
return defaultValue;
}
}
/**
* Determine whether standard input is an interactive stream. If the Java system property
* {@code python.launcher.tty} is defined and equal to {@code true} or {@code false}, then that
* provides the result. This property is normally supplied by the launcher. In the absence of
* this certainty, we use {@link #haveConsole()}.
*
* @return true if (we think) standard input is an interactive stream
*/
public static boolean isInteractive() {
// python.launcher.tty is authoritative; see http://bugs.jython.org/issue2325
String tty = getSystemProperty("python.launcher.tty", "");
if (tty.equalsIgnoreCase("true")) {
return true;
} else if (tty.equalsIgnoreCase("false")) {
return false;
} else {
// See if we have access to System.console()
return haveConsole();
}
}
/** Return {@code true} iff the console is accessible through System.console(). */
public static boolean haveConsole() {
try {
return System.console() != null;
} catch (SecurityException se) {
return false;
}
}
/**
* Check whether an input stream is interactive. This emulates CPython
* {@code Py_FdIsInteractive} within the constraints of pure Java. The input stream is
* considered ``interactive'' if either
*
* - it is {@code System.in} and {@link #isInteractive()} is {@code true}, or
* - the {@code -i} flag was given ({@link Options#interactive}={@code true}), and the
* filename associated with it is {@code null} or {@code "
"} or {@code "???"}.
*
*
* @param fp stream (tested only for {@code System.in})
* @param filename
* @return true iff thought to be interactive
*/
public static boolean isInteractive(InputStream fp, String filename) {
if (fp == System.in && isInteractive()) {
return true;
} else if (!Options.interactive) {
return false;
} else {
return filename == null || filename.equals("") || filename.equals("???");
}
}
/**
* Infers the usual Jython executable name from the position of the jar-file returned by
* {@link #getJarFileName()} by replacing the file name with "bin/jython". This is intended as
* an easy fallback for cases where {@code sys.executable} is {@code None} due to direct
* launching via the java executable.
*
* Note that this does not necessarily return the actual executable, but instead infers the
* place where it is usually expected to be. Use {@code sys.executable} to get the actual
* executable (may be {@code None}.
*
* @return usual Jython-executable as absolute path
*/
public static String getDefaultExecutableName() {
return getDefaultBinDir() + File.separator
+ (Platform.IS_WINDOWS ? "jython.exe" : "jython");
}
/**
* Infers the usual Jython bin-dir from the position of the jar-file returned by
* {@link #getJarFileName()} byr replacing the file name with "bin". This is intended as an easy
* fallback for cases where {@code sys.executable} is {@code null} due to direct launching via
* the java executable.
*
* Note that this does not necessarily return the actual bin-directory, but instead infers the
* place where it is usually expected to be.
*
* @return usual Jython bin-dir as absolute path
*/
public static String getDefaultBinDir() {
String jar = _getJarFileName();
return jar.substring(0, jar.lastIndexOf(File.separatorChar) + 1) + "bin";
}
/**
* Utility-method to obtain the name (including absolute path) of the currently used
* jython-jar-file. Usually this is jython.jar, but can also be jython-dev.jar or
* jython-standalone.jar or something custom.
*
* @return the full name of the jar file containing this class, null if not
* available.
*/
public static String getJarFileName() {
String jar = _getJarFileName();
return jar;
}
/**
* Utility-method to obtain the name (including absolute path) of the currently used
* jython-jar-file. Usually this is jython.jar, but can also be jython-dev.jar or
* jython-standalone.jar or something custom.
*
* @return the full name of the jar file containing this class, null if not
* available.
*/
private static String _getJarFileName() {
Class thisClass = PrePy.class;
String fullClassName = thisClass.getName();
String className = fullClassName.substring(fullClassName.lastIndexOf(".") + 1);
URL url = thisClass.getResource(className + ".class");
return getJarFileNameFromURL(url);
}
/**
* Return the path in the file system (as a string) of a JAR located using the URL of a class
* file that it contains. Classes in Java can be asked for the URL of their associated resources
* (including their own class definition), and so the caller of this method may present such a
* URL as the basis for locating the JAR from which it came.
*
* Three protocols are supported, Java JAR-file protocol, and two JBoss protocols "vfs" and
* "vfszip".
*
* The JAR-file protocol URL, which must be a {@code jar:file:} reference to a contained element
* (that is, it has a "!/" part) is able to identify an actual JAR in a file system that may
* then be opened using {@code jarFile = new JarFile(jarFileName)}. The path to the JAR is
* returned. If the JAR is accessed by another mechanism ({@code http:} say) this will fail.
*
* The JBoss URL must be a reference to a class in {@code vfs:/org/python/core/}, or the
* same thing using the {@code vfszip:} protocol, where <JAR> stands for the absolute path
* to the Jython JAR in VFS. There is no "!/" marker: in JBoss VFS a JAR is treated just like a
* directory and can no longer be opened as a JAR. The method essentially just swaps a VFS
* protocol for the Java {@code file:} protocol. The path returned will be correct only if this
* naive swap is valid.
*
* @param url into the JAR
* @return the file path or {@code null} in the event of a detectable error
*/
public static String getJarFileNameFromURL(URL url) {
URI fileURI = null;
try {
switch (url == null ? "" : url.getProtocol()) {
case "jar":
// url is jar:file:/some/path/some.jar!/package/with/A.class
if (Platform.IS_WINDOWS) {
// ... or jar:file://host/some/path/some.jar!/package/with/A.class
// ... or jar:file:////host/some/path/some.jar!/package/with/A.class
url = tweakWindowsFileURL(url);
}
URLConnection c = url.openConnection();
fileURI = ((JarURLConnection) c).getJarFileURL().toURI();
break;
case "vfs":
case "vfszip":
// path is /some/path/some-jython.jar/org/python/core/some-name.class
String path = url.getPath();
Pattern p = Pattern.compile("/([^./]+\\.jar)/org/python/core/\\w+.class");
Matcher m = p.matcher(path);
if (m.find()) {
// path contains the target class in a JAR (named in group 1).
// Make a file URL from all the text up to the end of group 1.
fileURI = new URL("file:" + path.substring(0, m.end(1))).toURI();
}
break;
default:
// Unknown protocol or url==null: fileURI = null
break;
}
} catch (IOException | URISyntaxException | IllegalArgumentException e) {
// Handler cannot open connection or URL is malformed some way: fileURI = null
}
// The JAR file is now identified in fileURI but needs decoding to a file
return fileURI == null ? null : new File(fileURI).toString();
}
/**
* If the argument is a {@code jar:file:} or {@code file:} URL, compensate for a bug in Java's
* construction of URLs affecting {@code java.io.File} and {@code java.net.URLConnection} on
* Windows. This is a helper for {@link #getJarFileNameFromURL(URL)}.
*
* This bug bites when a JAR file is at a (Windows) UNC location, and a {@code jar:file:} URL is
* derived from {@code Class.getResource()} as it is in {@link #_getJarFileName()}. When URL is
* supplied to {@link #getJarFileNameFromURL(URL)}, the bug leads to a URI that falsely treats a
* server as an "authority". It subsequently causes an {@code IllegalArgumentException} with the
* message "URI has an authority component" when we try to construct a File. See
* {@link https://bugs.java.com/view_bug.do?bug_id=6360233} ("won't fix").
*
* @param url Possibly malformed URL
* @return corrected URL
*/
private static URL tweakWindowsFileURL(URL url) throws MalformedURLException {
String urlstr = url.toString();
int fileIndex = urlstr.indexOf("file://"); // 7 chars
if (fileIndex >= 0) {
// Intended UNC path. If there is no slash following these two, insert "/" here:
int insert = fileIndex + 7;
if (urlstr.length() > insert && urlstr.charAt(insert) != '/') {
url = new URL(urlstr.substring(0, insert) + "//" + urlstr.substring(insert));
}
}
return url;
}
/**
* Run a command as a sub-process and return as the result the first line of output that
* consists of more than white space. It returns "" on any kind of error.
*
* @param command as strings (as for ProcessBuilder)
* @return the first line with content, or ""
*/
public static String getCommandResult(String... command) {
String result = "", line = null;
ProcessBuilder pb = new ProcessBuilder(command);
try {
Process p = pb.start();
java.io.BufferedReader br =
new java.io.BufferedReader(new java.io.InputStreamReader(p.getInputStream()));
// We read to the end-of-stream in case the sub-process cannot end cleanly without.
while ((line = br.readLine()) != null) {
if (line.length() > 0 && result.length() == 0) {
// This is the first line with content (maybe).
result = line.trim();
}
}
br.close();
// Now we wait for the sub-process to terminate nicely.
if (p.waitFor() != 0) {
// Bad exit status: don't take the result.
result = "";
}
} catch (IOException | InterruptedException | SecurityException e) {
result = "";
}
return result;
}
}