Add naive Windows Java detection - JavaUtils for finding it on other systems (incomplete)

CMakeLists.txt

@@ -300,6 +300,9 @@ logic/tasks/ProgressProvider.h
 logic/tasks/Task.h
 logic/tasks/Task.cpp
 
+# Utilities
+logic/JavaUtils.h
+logic/JavaUtils.cpp
 
 )
 

gui/settingsdialog.cpp

@@ -13,10 +13,11 @@
  * limitations under the License.
  */
 
+#include <MultiMC.h>
 #include "settingsdialog.h"
 #include "ui_settingsdialog.h"
+#include "logic/JavaUtils.h"
 
-#include <MultiMC.h>
 #include <settingsobject.h>
 #include <QFileDialog>
 #include <QMessageBox>
@@ -180,3 +181,11 @@ void SettingsDialog::loadSettings(SettingsObject *s)
 	ui->preLaunchCmdTextBox->setText(s->get("PreLaunchCommand").toString());
 	ui->postExitCmdTextBox->setText(s->get("PostExitCommand").toString());
 }
+
+void SettingsDialog::on_pushButton_clicked()
+{
+	JavaUtils jut;
+	QStringList paths = jut.FindJavaPath();
+
+	ui->javaPathTextBox->setText(paths.at(0));
+}

gui/settingsdialog.h

@@ -53,6 +53,8 @@ private slots:
 	
 	void on_buttonBox_accepted();
 	
+	void on_pushButton_clicked();
+
 private:
 	Ui::SettingsDialog *ui;
 };

gui/settingsdialog.ui

@@ -33,7 +33,7 @@
       <enum>QTabWidget::Rounded</enum>
      </property>
      <property name="currentIndex">
-      <number>0</number>
+      <number>2</number>
      </property>
      <widget class="QWidget" name="generalTab">
       <attribute name="title">

logic/JavaUtils.cpp

@@ -0,0 +1,114 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * 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.
+ */
+
+#include "JavaUtils.h"
+#include "osutils.h"
+#include "pathutils.h"
+
+#include <QStringList>
+#include <QString>
+#include <QDir>
+#include <QDebug>
+
+#if WINDOWS
+#include <windows.h>
+
+#endif
+
+JavaUtils::JavaUtils()
+{
+
+}
+
+#if WINDOWS
+QStringList JavaUtils::FindJavaPath()
+{
+	QStringList paths;
+
+	HKEY jreKey;
+	QString jreKeyName = "SOFTWARE\\JavaSoft\\Java Runtime Environment";
+	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, jreKeyName.toStdString().c_str(), 0, KEY_READ | KEY_WOW64_64KEY, &jreKey) == ERROR_SUCCESS)
+	{
+		// Read the current JRE version from the registry.
+		// This will be used to find the key that contains the JavaHome value.
+		char *value = new char[0];
+		DWORD valueSz = 0;
+		if (RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE*)value, &valueSz) == ERROR_MORE_DATA)
+		{
+			value = new char[valueSz];
+			RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE*)value, &valueSz);
+		}
+
+		RegCloseKey(jreKey);
+
+		// Now open the registry key for the JRE version that we just got.
+		jreKeyName.append("\\").append(value);
+		if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, jreKeyName.toStdString().c_str(), 0, KEY_READ | KEY_WOW64_64KEY, &jreKey) == ERROR_SUCCESS)
+		{
+			// Read the JavaHome value to find where Java is installed.
+			value = new char[0];
+			valueSz = 0;
+			if (RegQueryValueExA(jreKey, "JavaHome", NULL, NULL, (BYTE*)value, &valueSz) == ERROR_MORE_DATA)
+			{
+				value = new char[valueSz];
+				RegQueryValueExA(jreKey, "JavaHome", NULL, NULL, (BYTE*)value, &valueSz);
+
+				paths << QDir(PathCombine(value, "bin")).absoluteFilePath("java.exe");
+			}
+
+			RegCloseKey(jreKey);
+		}
+	}
+
+	if(paths.length() <= 0)
+	{
+		qWarning() << "Failed to find Java in the Windows registry - defaulting to \"java\"";
+		paths << "java";
+	}
+
+	return paths;
+}
+#elif OSX
+QStringList JavaUtils::FindJavaPath()
+{
+	qWarning() << "OS X Java detection incomplete - defaulting to \"java\"";
+
+	QStringList paths;
+	paths << "java";
+
+	return paths;
+}
+
+#elif LINUX
+QStringList JavaUtils::FindJavaPath()
+{
+	qWarning() << "Linux Java detection incomplete - defaulting to \"java\"";
+
+	QStringList paths;
+	paths << "java";
+
+	return paths;
+}
+#else
+QStringList JavaUtils::FindJavaPath()
+{
+	qWarning() << "Unknown operating system build - defaulting to \"java\"";
+
+	QStringList paths;
+	paths << "java";
+
+	return paths;
+}
+#endif

logic/JavaUtils.h

@@ -0,0 +1,26 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <QStringList>
+
+class JavaUtils
+{
+public:
+	JavaUtils();
+
+	QStringList FindJavaPath();
+};