jdk/src/windows/classes/java/lang/ProcessEnvironment.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/windows/classes/java/lang/ProcessEnvironment.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,321 @@
+/*
+ * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/* We use APIs that access a so-called Windows "Environment Block",
+ * which looks like an array of jchars like this:
+ *
+ * FOO=BAR\u0000 ... GORP=QUUX\u0000\u0000
+ *
+ * This data structure has a number of peculiarities we must contend with:
+ * (see: http://windowssdk.msdn.microsoft.com/en-us/library/ms682009.aspx)
+ * - The NUL jchar separators, and a double NUL jchar terminator.
+ *   It appears that the Windows implementation requires double NUL
+ *   termination even if the environment is empty.  We should always
+ *   generate environments with double NUL termination, while accepting
+ *   empty environments consisting of a single NUL.
+ * - on Windows9x, this is actually an array of 8-bit chars, not jchars,
+ *   encoded in the system default encoding.
+ * - The block must be sorted by Unicode value, case-insensitively,
+ *   as if folded to upper case.
+ * - There are magic environment variables maintained by Windows
+ *   that start with a `=' (!) character.  These are used for
+ *   Windows drive current directory (e.g. "=C:=C:\WINNT") or the
+ *   exit code of the last command (e.g. "=ExitCode=0000001").
+ *
+ * Since Java and non-9x Windows speak the same character set, and
+ * even the same encoding, we don't have to deal with unreliable
+ * conversion to byte streams.  Just add a few NUL terminators.
+ *
+ * System.getenv(String) is case-insensitive, while System.getenv()
+ * returns a map that is case-sensitive, which is consistent with
+ * native Windows APIs.
+ *
+ * The non-private methods in this class are not for general use even
+ * within this package.  Instead, they are the system-dependent parts
+ * of the system-independent method of the same name.  Don't even
+ * think of using this class unless your method's name appears below.
+ *
+ * @author Martin Buchholz
+ * @since 1.5
+ */
+
+package java.lang;
+
+import java.io.*;
+import java.util.*;
+
+final class ProcessEnvironment extends HashMap<String,String>
+{
+    private static String validateName(String name) {
+        // An initial `=' indicates a magic Windows variable name -- OK
+        if (name.indexOf('=', 1)   != -1 ||
+            name.indexOf('\u0000') != -1)
+            throw new IllegalArgumentException
+                ("Invalid environment variable name: \"" + name + "\"");
+        return name;
+    }
+
+    private static String validateValue(String value) {
+        if (value.indexOf('\u0000') != -1)
+            throw new IllegalArgumentException
+                ("Invalid environment variable value: \"" + value + "\"");
+        return value;
+    }
+
+    private static String nonNullString(Object o) {
+        if (o == null)
+            throw new NullPointerException();
+        return (String) o;
+    }
+
+    public String put(String key, String value) {
+        return super.put(validateName(key), validateValue(value));
+    }
+
+    public String get(Object key) {
+        return super.get(nonNullString(key));
+    }
+
+    public boolean containsKey(Object key) {
+        return super.containsKey(nonNullString(key));
+    }
+
+    public boolean containsValue(Object value) {
+        return super.containsValue(nonNullString(value));
+    }
+
+    public String remove(Object key) {
+        return super.remove(nonNullString(key));
+    }
+
+    private static class CheckedEntry
+        implements Map.Entry<String,String>
+    {
+        private final Map.Entry<String,String> e;
+        public CheckedEntry(Map.Entry<String,String> e) {this.e = e;}
+        public String getKey()   { return e.getKey();}
+        public String getValue() { return e.getValue();}
+        public String setValue(String value) {
+            return e.setValue(validateValue(value));
+        }
+        public String toString() { return getKey() + "=" + getValue();}
+        public boolean equals(Object o) {return e.equals(o);}
+        public int hashCode()    {return e.hashCode();}
+    }
+
+    private static class CheckedEntrySet
+        extends AbstractSet<Map.Entry<String,String>>
+    {
+        private final Set<Map.Entry<String,String>> s;
+        public CheckedEntrySet(Set<Map.Entry<String,String>> s) {this.s = s;}
+        public int size()        {return s.size();}
+        public boolean isEmpty() {return s.isEmpty();}
+        public void clear()      {       s.clear();}
+        public Iterator<Map.Entry<String,String>> iterator() {
+            return new Iterator<Map.Entry<String,String>>() {
+                Iterator<Map.Entry<String,String>> i = s.iterator();
+                public boolean hasNext() { return i.hasNext();}
+                public Map.Entry<String,String> next() {
+                    return new CheckedEntry(i.next());
+                }
+                public void remove() { i.remove();}
+            };
+        }
+        private static Map.Entry<String,String> checkedEntry (Object o) {
+            Map.Entry<String,String> e = (Map.Entry<String,String>) o;
+            nonNullString(e.getKey());
+            nonNullString(e.getValue());
+            return e;
+        }
+        public boolean contains(Object o) {return s.contains(checkedEntry(o));}
+        public boolean remove(Object o)   {return s.remove(checkedEntry(o));}
+    }
+
+    private static class CheckedValues extends AbstractCollection<String> {
+        private final Collection<String> c;
+        public CheckedValues(Collection<String> c) {this.c = c;}
+        public int size()                  {return c.size();}
+        public boolean isEmpty()           {return c.isEmpty();}
+        public void clear()                {       c.clear();}
+        public Iterator<String> iterator() {return c.iterator();}
+        public boolean contains(Object o)  {return c.contains(nonNullString(o));}
+        public boolean remove(Object o)    {return c.remove(nonNullString(o));}
+    }
+
+    private static class CheckedKeySet extends AbstractSet<String> {
+        private final Set<String> s;
+        public CheckedKeySet(Set<String> s) {this.s = s;}
+        public int size()                  {return s.size();}
+        public boolean isEmpty()           {return s.isEmpty();}
+        public void clear()                {       s.clear();}
+        public Iterator<String> iterator() {return s.iterator();}
+        public boolean contains(Object o)  {return s.contains(nonNullString(o));}
+        public boolean remove(Object o)    {return s.remove(nonNullString(o));}
+    }
+
+    public Set<String> keySet() {
+        return new CheckedKeySet(super.keySet());
+    }
+
+    public Collection<String> values() {
+        return new CheckedValues(super.values());
+    }
+
+    public Set<Map.Entry<String,String>> entrySet() {
+        return new CheckedEntrySet(super.entrySet());
+    }
+
+
+    private static final class NameComparator
+        implements Comparator<String> {
+        public int compare(String s1, String s2) {
+            // We can't use String.compareToIgnoreCase since it
+            // canonicalizes to lower case, while Windows
+            // canonicalizes to upper case!  For example, "_" should
+            // sort *after* "Z", not before.
+            int n1 = s1.length();
+            int n2 = s2.length();
+            int min = Math.min(n1, n2);
+            for (int i = 0; i < min; i++) {
+                char c1 = s1.charAt(i);
+                char c2 = s2.charAt(i);
+                if (c1 != c2) {
+                    c1 = Character.toUpperCase(c1);
+                    c2 = Character.toUpperCase(c2);
+                    if (c1 != c2)
+                        // No overflow because of numeric promotion
+                        return c1 - c2;
+                }
+            }
+            return n1 - n2;
+        }
+    }
+
+    private static final class EntryComparator
+        implements Comparator<Map.Entry<String,String>> {
+        public int compare(Map.Entry<String,String> e1,
+                           Map.Entry<String,String> e2) {
+            return nameComparator.compare(e1.getKey(), e2.getKey());
+        }
+    }
+
+    // Allow `=' as first char in name, e.g. =C:=C:\DIR
+    static final int MIN_NAME_LENGTH = 1;
+
+    private static final NameComparator nameComparator;
+    private static final EntryComparator entryComparator;
+    private static final ProcessEnvironment theEnvironment;
+    private static final Map<String,String> theUnmodifiableEnvironment;
+    private static final Map<String,String> theCaseInsensitiveEnvironment;
+
+    static {
+        nameComparator  = new NameComparator();
+        entryComparator = new EntryComparator();
+        theEnvironment  = new ProcessEnvironment();
+        theUnmodifiableEnvironment
+            = Collections.unmodifiableMap(theEnvironment);
+
+        String envblock = environmentBlock();
+        int beg, end, eql;
+        for (beg = 0;
+             ((end = envblock.indexOf('\u0000', beg  )) != -1 &&
+              // An initial `=' indicates a magic Windows variable name -- OK
+              (eql = envblock.indexOf('='     , beg+1)) != -1);
+             beg = end + 1) {
+            // Ignore corrupted environment strings.
+            if (eql < end)
+                theEnvironment.put(envblock.substring(beg, eql),
+                                   envblock.substring(eql+1,end));
+        }
+
+        theCaseInsensitiveEnvironment
+            = new TreeMap<String,String>(nameComparator);
+        theCaseInsensitiveEnvironment.putAll(theEnvironment);
+    }
+
+    private ProcessEnvironment() {
+        super();
+    }
+
+    private ProcessEnvironment(int capacity) {
+        super(capacity);
+    }
+
+    // Only for use by System.getenv(String)
+    static String getenv(String name) {
+        // The original implementation used a native call to _wgetenv,
+        // but it turns out that _wgetenv is only consistent with
+        // GetEnvironmentStringsW (for non-ASCII) if `wmain' is used
+        // instead of `main', even in a process created using
+        // CREATE_UNICODE_ENVIRONMENT.  Instead we perform the
+        // case-insensitive comparison ourselves.  At least this
+        // guarantees that System.getenv().get(String) will be
+        // consistent with System.getenv(String).
+        return theCaseInsensitiveEnvironment.get(name);
+    }
+
+    // Only for use by System.getenv()
+    static Map<String,String> getenv() {
+        return theUnmodifiableEnvironment;
+    }
+
+    // Only for use by ProcessBuilder.environment()
+    static Map<String,String> environment() {
+        return (Map<String,String>) theEnvironment.clone();
+    }
+
+    // Only for use by Runtime.exec(...String[]envp...)
+    static Map<String,String> emptyEnvironment(int capacity) {
+        return new ProcessEnvironment(capacity);
+    }
+
+    private static native String environmentBlock();
+
+    // Only for use by ProcessImpl.start()
+    String toEnvironmentBlock() {
+        // Sort Unicode-case-insensitively by name
+        List<Map.Entry<String,String>> list
+            = new ArrayList<Map.Entry<String,String>>(entrySet());
+        Collections.sort(list, entryComparator);
+
+        StringBuilder sb = new StringBuilder(size()*30);
+        for (Map.Entry<String,String> e : list)
+            sb.append(e.getKey())
+              .append('=')
+              .append(e.getValue())
+              .append('\u0000');
+        // Ensure double NUL termination,
+        // even if environment is empty.
+        if (sb.length() == 0)
+            sb.append('\u0000');
+        sb.append('\u0000');
+        return sb.toString();
+    }
+
+    static String toEnvironmentBlock(Map<String,String> map) {
+        return map == null ? null :
+            ((ProcessEnvironment)map).toEnvironmentBlock();
+    }
+}