feat: Investigate using OSProcessHandler

Fixes #153

Signed-off-by: azerr <azerr@redhat.com>

src/main/java/com/redhat/devtools/lsp4ij/server/CannotStartProcessException.java

@@ -13,14 +13,12 @@
  *******************************************************************************/
 package com.redhat.devtools.lsp4ij.server;
 
-import java.io.IOException;
-
 /**
  * Language server exception when start process cannot be done.
  */
 public class CannotStartProcessException extends LanguageServerException {
 
-    public CannotStartProcessException(IOException e) {
+    public CannotStartProcessException(Exception e) {
         super(e);
     }
 

src/main/java/com/redhat/devtools/lsp4ij/server/OSProcessStreamConnectionProvider.java

@@ -0,0 +1,79 @@
+package com.redhat.devtools.lsp4ij.server;
+
+import com.intellij.execution.ExecutionException;
+import com.intellij.execution.configurations.GeneralCommandLine;
+import com.intellij.execution.impl.ExecutionManagerImpl;
+import com.intellij.execution.process.OSProcessHandler;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Objects;
+
+public class OSProcessStreamConnectionProvider implements StreamConnectionProvider {
+
+    private GeneralCommandLine commandLine;
+    private OSProcessHandler processHandler;
+
+    public OSProcessStreamConnectionProvider(GeneralCommandLine commandLine) {
+        this.commandLine = commandLine;
+    }
+
+    public void setCommandLine(GeneralCommandLine commandLine) {
+        this.commandLine = commandLine;
+    }
+
+    public GeneralCommandLine getCommandLine() {
+        return commandLine;
+    }
+
+    @Override
+    public void start() throws CannotStartProcessException {
+        if (this.commandLine == null) {
+            throw new CannotStartProcessException("Unable to start language server: " + this);
+        }
+        try {
+           processHandler = new OSProcessHandler(commandLine);
+        } catch (ExecutionException e) {
+            throw new CannotStartProcessException(e);
+        }
+    }
+
+    @Override
+    public boolean isAlive() {
+        return processHandler != null && processHandler.isStartNotified() && !processHandler.isProcessTerminated();
+    }
+
+    @Override
+    public InputStream getInputStream() {
+        return processHandler.getProcess().getInputStream();
+    }
+
+    @Override
+    public OutputStream getOutputStream() {
+        return processHandler.getProcessInput();
+    }
+
+    @Override
+    public @Nullable InputStream getErrorStream() {
+        return null;
+    }
+
+    @Override
+    public void stop() {
+        if (processHandler != null && !processHandler.isProcessTerminated()) {
+            ExecutionManagerImpl.stopProcess(processHandler);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.getCommandLine());
+    }
+
+    @Override
+    public String toString() {
+        return "OSProcessStreamConnectionProvider [commandLine=" + this.getCommandLine() + "]";
+    }
+
+}

src/main/java/com/redhat/devtools/lsp4ij/server/definition/launching/UserDefinedStreamConnectionProvider.java

@@ -13,7 +13,10 @@
  *******************************************************************************/
 package com.redhat.devtools.lsp4ij.server.definition.launching;
 
+import com.intellij.execution.configurations.GeneralCommandLine;
 import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.util.EnvironmentUtil;
+import com.redhat.devtools.lsp4ij.server.OSProcessStreamConnectionProvider;
 import com.redhat.devtools.lsp4ij.server.ProcessStreamConnectionProvider;
 import org.jetbrains.annotations.NotNull;
 
@@ -23,20 +26,31 @@
  * {@link ProcessStreamConnectionProvider} implementation to start a language server with a
  * process command defined by the user.
  */
-public class UserDefinedStreamConnectionProvider extends ProcessStreamConnectionProvider {
+public class UserDefinedStreamConnectionProvider extends OSProcessStreamConnectionProvider {
 
     private final @NotNull UserDefinedLanguageServerDefinition serverDefinition;
 
     public UserDefinedStreamConnectionProvider(@NotNull String commandLine,
                                                @NotNull Map<String, String> userEnvironmentVariables,
                                                boolean includeSystemEnvironmentVariables,
                                                @NotNull UserDefinedLanguageServerDefinition serverDefinition) {
-        super.setCommands(CommandUtils.createCommands(commandLine));
-        super.setUserEnvironmentVariables(userEnvironmentVariables);
-        super.setIncludeSystemEnvironmentVariables(includeSystemEnvironmentVariables);
+        super(createCommandLine(commandLine, userEnvironmentVariables, includeSystemEnvironmentVariables));
         this.serverDefinition = serverDefinition;
     }
 
+    @NotNull
+    private static GeneralCommandLine createCommandLine(@NotNull String commandLine,
+                                                        @NotNull Map<String, String> userEnvironmentVariables,
+                                                        boolean includeSystemEnvironmentVariables) {
+        Map<String, String> environmentVariables = userEnvironmentVariables;
+        // Add System environment variables
+        if (includeSystemEnvironmentVariables) {
+            environmentVariables.putAll(EnvironmentUtil.getEnvironmentMap());
+        }
+        return new GeneralCommandLine(CommandUtils.createCommands(commandLine))
+                .withEnvironment(environmentVariables);
+    }
+
     @Override
     public Object getInitializationOptions(VirtualFile rootUri) {
         return serverDefinition.getLanguageServerInitializationOptions();