Implemented get and set environment variables for posix.

readme.md

@@ -16,6 +16,7 @@ These APIs support Java 5 and later. Some of these APIs overlap with APIs availa
 
 * Get the PID of the current process.
 * Get and set the process working directory.
+* Get and set the process environment variables.
 
 ### Terminal and console
 

src/main/cpp/posix.cpp

@@ -168,6 +168,34 @@ Java_net_rubygrapefruit_platform_internal_jni_PosixProcessFunctions_setWorkingDi
     free(path);
 }
 
+JNIEXPORT jstring JNICALL
+Java_net_rubygrapefruit_platform_internal_jni_PosixProcessFunctions_getEnvironmentVariable(JNIEnv *env, jclass target, jstring var, jobject result) {
+    char* varStr = java_to_char(env, var, result);
+    char* valueStr = getenv(varStr);
+    free(varStr);
+    if (valueStr == NULL) {
+        return NULL;
+    }
+    return char_to_java(env, valueStr, result);
+}
+
+JNIEXPORT void JNICALL
+Java_net_rubygrapefruit_platform_internal_jni_PosixProcessFunctions_setEnvironmentVariable(JNIEnv *env, jclass target, jstring var, jstring value, jobject result) {
+    char* varStr = java_to_char(env, var, result);
+    if (value == NULL) {
+        if (setenv(varStr, "", 1) != 0) {
+            mark_failed_with_errno(env, "could not putenv()", result);
+        }
+    } else {
+        char* valueStr = java_to_char(env, value, result);
+        if (setenv(varStr, valueStr, 1) != 0) {
+            mark_failed_with_errno(env, "could not putenv()", result);
+        }
+        free(valueStr);
+    }
+    free(varStr);
+}
+
 /*
  * Terminal functions
  */

src/main/java/net/rubygrapefruit/platform/Process.java

@@ -50,7 +50,8 @@ public interface Process extends NativeIntegration {
     /**
      * Get the value of an environment variable.
      *
-     * @return The value or null if no such environment variable.
+     * @return The value or null if no such environment variable. Also returns null for an environment variable whose
+     *         value is an empty string.
      * @throws NativeException On failure.
      */
     @ThreadSafe
@@ -59,8 +60,9 @@ public interface Process extends NativeIntegration {
     /**
      * Sets the value of an environment variable.
      *
-     * @param value the new value. Use null to remove the environment variable. Note that on some platforms it is not
+     * @param value the new value. Use null or an empty string to remove the environment variable. Note that on some
-     * possible to remove the environment variable. On such platforms, the value is set to an empty string instead.
+     * platforms it is not possible to remove the environment variable safely. On such platforms, the value is set to an
+     * empty string instead.
      * @throws NativeException On failure.
      */
     @ThreadSafe

src/main/java/net/rubygrapefruit/platform/internal/DefaultProcess.java

@@ -23,56 +23,45 @@ import net.rubygrapefruit.platform.internal.jni.PosixProcessFunctions;
 import java.io.File;
 
 public class DefaultProcess implements Process {
-    private final Object workingDirectoryLock = new Object();
-    private final Object environmentLock = new Object();
-
     public int getProcessId() throws NativeException {
         return PosixProcessFunctions.getPid();
     }
 
     public File getWorkingDirectory() throws NativeException {
         FunctionResult result = new FunctionResult();
-        synchronized (workingDirectoryLock) {
+        String dir = PosixProcessFunctions.getWorkingDirectory(result);
-            String dir = PosixProcessFunctions.getWorkingDirectory(result);
+        if (result.isFailed()) {
-            if (result.isFailed()) {
+            throw new NativeException(String.format("Could not get process working directory: %s",
-                throw new NativeException(String.format("Could not get process working directory: %s",
+                    result.getMessage()));
-                        result.getMessage()));
-            }
-            return new File(dir);
         }
+        return new File(dir);
     }
 
     public void setWorkingDirectory(File directory) throws NativeException {
         FunctionResult result = new FunctionResult();
-        synchronized (workingDirectoryLock) {
+        PosixProcessFunctions.setWorkingDirectory(directory.getAbsolutePath(), result);
-            PosixProcessFunctions.setWorkingDirectory(directory.getAbsolutePath(), result);
+        if (result.isFailed()) {
-            if (result.isFailed()) {
+            throw new NativeException(String.format("Could not set process working directory to '%s': %s",
-                throw new NativeException(String.format("Could not set process working directory: %s",
+                    directory.getAbsoluteFile(), result.getMessage()));
-                        result.getMessage()));
-            }
-            System.setProperty("user.dir", directory.getAbsolutePath());
         }
     }
 
     public String getEnvironmentVariable(String name) throws NativeException {
         FunctionResult result = new FunctionResult();
-        String value;
+        String value = PosixProcessFunctions.getEnvironmentVariable(name, result);
-        synchronized (environmentLock) {
-            value = PosixProcessFunctions.getEnvironmentVariable(name, result);
-        }
         if (result.isFailed()) {
-            throw new NativeException(String.format("Could not get the value of environment variable '%s': %s", name, result.getMessage()));
+            throw new NativeException(String.format("Could not get the value of environment variable '%s': %s", name,
+                    result.getMessage()));
         }
         return value;
     }
 
     public void setEnvironmentVariable(String name, String value) throws NativeException {
         FunctionResult result = new FunctionResult();
-        synchronized (environmentLock) {
+        PosixProcessFunctions.setEnvironmentVariable(name, value, result);
-            PosixProcessFunctions.setEnvironmentVariable(name, value, result);
-        }
         if (result.isFailed()) {
-            throw new NativeException(String.format("Could not set the value of environment variable '%s': %s", name, result.getMessage()));
+            throw new NativeException(String.format("Could not set the value of environment variable '%s': %s", name,
+                    result.getMessage()));
         }
     }
 }

src/main/java/net/rubygrapefruit/platform/internal/Platform.java

@@ -91,7 +91,7 @@ public abstract class Platform {
         @Override
         public <T extends NativeIntegration> T get(Class<T> type, NativeLibraryLoader nativeLibraryLoader) {
             if (type.equals(Process.class)) {
-                return type.cast(new DefaultProcess());
+                return type.cast(new WrapperProcess(new DefaultProcess()));
             }
             if (type.equals(Terminals.class)) {
                 return type.cast(new WindowsTerminals());
@@ -129,7 +129,7 @@ public abstract class Platform {
                 return type.cast(new DefaultPosixFile());
             }
             if (type.equals(Process.class)) {
-                return type.cast(new DefaultProcess());
+                return type.cast(new WrapperProcess(new DefaultProcess()));
             }
             if (type.equals(Terminals.class)) {
                 nativeLibraryLoader.load(getCursesLibraryName());

src/main/java/net/rubygrapefruit/platform/internal/WrapperProcess.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2012 Adam Murdoch
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package net.rubygrapefruit.platform.internal;
+
+import net.rubygrapefruit.platform.NativeException;
+import net.rubygrapefruit.platform.Process;
+import net.rubygrapefruit.platform.ThreadSafe;
+
+import java.io.File;
+import java.lang.reflect.Field;
+import java.util.Map;
+
+/**
+ * A {@link Process} implementation that wraps another to add thread-safety and to update the JVM's internal view of
+ * various process properties.
+ */
+@ThreadSafe
+public class WrapperProcess implements Process {
+    private final Process process;
+    private final Object workingDirectoryLock = new Object();
+    private final Object environmentLock = new Object();
+
+    public WrapperProcess(Process process) {
+        this.process = process;
+    }
+
+    @Override
+    public String toString() {
+        return process.toString();
+    }
+
+    public int getProcessId() throws NativeException {
+        return process.getProcessId();
+    }
+
+    public File getWorkingDirectory() throws NativeException {
+        synchronized (workingDirectoryLock) {
+            return process.getWorkingDirectory();
+        }
+    }
+
+    public void setWorkingDirectory(File directory) throws NativeException {
+        synchronized (workingDirectoryLock) {
+            process.setWorkingDirectory(directory);
+            System.setProperty("user.dir", directory.getAbsolutePath());
+        }
+    }
+
+    public String getEnvironmentVariable(String name) throws NativeException {
+        synchronized (environmentLock) {
+            String value = process.getEnvironmentVariable(name);
+            return value == null || value.length() == 0 ? null : value;
+        }
+    }
+
+    public void setEnvironmentVariable(String name, String value) throws NativeException {
+        synchronized (environmentLock) {
+            if (value == null || value.length() == 0) {
+                process.setEnvironmentVariable(name, null);
+                removeEnvInternal(name);
+            } else {
+                process.setEnvironmentVariable(name, value);
+                setEnvInternal(name, value);
+            }
+        }
+    }
+
+    private void removeEnvInternal(String name) {
+        getEnv().remove(name);
+    }
+
+    private void setEnvInternal(String name, String value) {
+        getEnv().put(name, value);
+    }
+
+    private Map<String, String> getEnv() {
+        try {
+            Map<String, String> theUnmodifiableEnvironment = System.getenv();
+            Class<?> cu = theUnmodifiableEnvironment.getClass();
+            Field m = cu.getDeclaredField("m");
+            m.setAccessible(true);
+            return (Map<String, String>)m.get(theUnmodifiableEnvironment);
+        } catch (Exception e) {
+            throw new NativeException("Unable to get mutable environment map.", e);
+        }
+    }
+
+}

src/test/groovy/net/rubygrapefruit/platform/ProcessTest.groovy

@@ -19,6 +19,7 @@ package net.rubygrapefruit.platform
 import org.junit.Rule
 import org.junit.rules.TemporaryFolder
 import spock.lang.Specification
+import spock.lang.Unroll
 
 class ProcessTest extends Specification {
     @Rule TemporaryFolder tmpDir
@@ -36,6 +37,7 @@ class ProcessTest extends Specification {
 
     def "can get and change working directory"() {
         def newDir = tmpDir.newFolder(dir).canonicalFile
+        assert newDir.directory
 
         when:
         def original = process.workingDirectory
@@ -67,7 +69,7 @@ class ProcessTest extends Specification {
 
         then:
         NativeException e = thrown()
-        e.message.startsWith("Could not set process working directory:")
+        e.message.startsWith("Could not set process working directory")
     }
 
     def "can get and set and remove environment variable"() {