From 8ee3464d8064ebe1694c7b20177878c0d9961451 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Thu, 9 Sep 2010 17:54:41 -0700
Subject: [PATCH] altosui: Display error dialog when AltOS JNI library can't be
 loaded

Having an error dialog appear at application startup seems better than
simply failing to present the device dialog later on.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 ao-tools/altosui/AltosDevice.java       | 77 ++++++++++++++++++++-----
 ao-tools/altosui/AltosDeviceDialog.java | 13 +++--
 ao-tools/altosui/AltosUI.java           | 14 +++++
 3 files changed, 85 insertions(+), 19 deletions(-)

diff --git a/ao-tools/altosui/AltosDevice.java b/ao-tools/altosui/AltosDevice.java
index e62a0a7a..9ae522c2 100644
--- a/ao-tools/altosui/AltosDevice.java
+++ b/ao-tools/altosui/AltosDevice.java
@@ -22,20 +22,67 @@ import libaltosJNI.*;
 
 public class AltosDevice extends altos_device {
 
-	static boolean initialized = false;
-	static {
-		try {
-			System.loadLibrary("altos");
-			libaltos.altos_init();
+	static public boolean initialized = false;
+	static public boolean loaded_library = false;
+
+	public static boolean load_library() {
+		if (!initialized) {
+			try {
+				System.loadLibrary("altos");
+				libaltos.altos_init();
+				loaded_library = true;
+			} catch (UnsatisfiedLinkError e) {
+				loaded_library = false;
+			}
 			initialized = true;
-		} catch (UnsatisfiedLinkError e) {
-			System.err.println("Native library failed to load.\n" + e);
 		}
+		return loaded_library;
+	}
+
+	static int usb_product_altusmetrum() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_ALTUSMETRUM;
+		return 0x000a;
+	}
+
+	static int usb_product_altusmetrum_min() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_ALTUSMETRUM_MIN;
+		return 0x000a;
+	}
+
+	static int usb_product_altusmetrum_max() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_ALTUSMETRUM_MAX;
+		return 0x000d;
+	}
+
+	static int usb_product_telemetrum() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_TELEMETRUM;
+		return 0x000b;
+	}
+
+	static int usb_product_teledongle() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_ALTUSMETRUM;
+		return 0x000c;
+	}
+
+	static int usb_product_teleterra() {
+		if (load_library())
+			return libaltosConstants.USB_PRODUCT_ALTUSMETRUM;
+		return 0x000d;
 	}
-	public final static int AltusMetrum = libaltosConstants.USB_PRODUCT_ALTUSMETRUM;
-	public final static int TeleMetrum = libaltosConstants.USB_PRODUCT_TELEMETRUM;
-	public final static int TeleDongle = libaltosConstants.USB_PRODUCT_TELEDONGLE;
-	public final static int TeleTerra = libaltosConstants.USB_PRODUCT_TELETERRA;
+
+	public final static int AltusMetrum = usb_product_altusmetrum();
+	public final static int TeleMetrum = usb_product_telemetrum();
+	public final static int TeleDongle = usb_product_teledongle();
+	public final static int TeleTerra = usb_product_teleterra();
+	public final static int AltusMetrumMin = usb_product_altusmetrum_min();
+	public final static int AltusMetrumMax = usb_product_altusmetrum_max();
+
+
 	public final static int Any = 0x10000;
 	public final static int BaseStation = 0x10000 + 1;
 
@@ -48,11 +95,11 @@ public class AltosDevice extends altos_device {
 	}
 
 	public boolean isAltusMetrum() {
-		if (getVendor() != libaltosConstants.USB_VENDOR_ALTUSMETRUM)
+		if (getVendor() != AltusMetrum)
 			return false;
-		if (getProduct() < libaltosConstants.USB_PRODUCT_ALTUSMETRUM_MIN)
+		if (getProduct() < AltusMetrumMin)
 			return false;
-		if (getProduct() > libaltosConstants.USB_PRODUCT_ALTUSMETRUM_MAX)
+		if (getProduct() > AltusMetrumMax)
 			return false;
 		return true;
 	}
@@ -80,7 +127,7 @@ public class AltosDevice extends altos_device {
 	}
 
 	static AltosDevice[] list(int product) {
-		if (!initialized)
+		if (!load_library())
 			return null;
 
 		SWIGTYPE_p_altos_list list = libaltos.altos_list_start();
diff --git a/ao-tools/altosui/AltosDeviceDialog.java b/ao-tools/altosui/AltosDeviceDialog.java
index 3df4c6eb..ec78e288 100644
--- a/ao-tools/altosui/AltosDeviceDialog.java
+++ b/ao-tools/altosui/AltosDeviceDialog.java
@@ -49,10 +49,15 @@ public class AltosDeviceDialog extends JDialog implements ActionListener {
 			dialog.setVisible(true);
 			return value;
 		} else {
-			JOptionPane.showMessageDialog(frame,
-						      "No AltOS devices available",
-						      "No AltOS devices",
-						      JOptionPane.ERROR_MESSAGE);
+			/* check for missing altos JNI library, which
+			 * will put up its own error dialog
+			 */
+			if (AltosUI.load_library(frame)) {
+				JOptionPane.showMessageDialog(frame,
+							      "No AltOS devices available",
+							      "No AltOS devices",
+							      JOptionPane.ERROR_MESSAGE);
+			}
 			return null;
 		}
 	}
diff --git a/ao-tools/altosui/AltosUI.java b/ao-tools/altosui/AltosUI.java
index 3aaeb888..ca587b25 100644
--- a/ao-tools/altosui/AltosUI.java
+++ b/ao-tools/altosui/AltosUI.java
@@ -70,8 +70,22 @@ public class AltosUI extends JFrame {
 
 	public AltosVoice voice = new AltosVoice();
 
+	public static boolean load_library(Frame frame) {
+		if (!AltosDevice.load_library()) {
+			JOptionPane.showMessageDialog(frame,
+						      String.format("No AltOS library in \"%s\"",
+								    System.getProperty("java.library.path","<undefined>")),
+						      "Cannot load device access library",
+						      JOptionPane.ERROR_MESSAGE);
+			return false;
+		}
+		return true;
+	}
+
 	public AltosUI() {
 
+		load_library(null);
+
 		String[] statusNames = { "Height (m)", "State", "RSSI (dBm)", "Speed (m/s)" };
 		Object[][] statusData = { { "0", "pad", "-50", "0" } };
 
-- 
2.30.2