X-Git-Url: https://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Fgui%2Fmap%2FDiskTileCacher.java;fp=src%2Ftim%2Fprune%2Fgui%2Fmap%2FDiskTileCacher.java;h=fd2042a7714acfe2ca1f5b47693ce9df06b0a79f;hp=0000000000000000000000000000000000000000;hb=ce6f2161b8596f7018d6a76bff79bc9e571f35fd;hpb=2d8cb72e84d5cc1089ce77baf1e34ea3ea2f8465

diff --git a/src/tim/prune/gui/map/DiskTileCacher.java b/src/tim/prune/gui/map/DiskTileCacher.java
new file mode 100644
index 0000000..fd2042a
--- /dev/null
+++ b/src/tim/prune/gui/map/DiskTileCacher.java
@@ -0,0 +1,174 @@
+package tim.prune.gui.map;
+
+import java.awt.Image;
+import java.awt.Toolkit;
+import java.awt.image.ImageObserver;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.HashSet;
+
+import tim.prune.GpsPrune;
+
+/**
+ * Class to control the reading and saving of map tiles
+ * to a cache on disk
+ */
+public class DiskTileCacher implements Runnable
+{
+	/** URL to get image from */
+	private URL _url = null;
+	/** File to save image to */
+	private File _file = null;
+	/** Observer to be notified */
+	private ImageObserver _observer = null;
+	/** Time limit to cache images for */
+	private static final long CACHE_TIME_LIMIT = 20 * 24 * 60 * 60 * 1000; // 20 days in ms
+	/** Hashset of all blocked / 404 tiles to avoid requesting them again */
+	private static final HashSet<String> BLOCKED_URLS = new HashSet<String>();
+
+	/**
+	 * Private constructor
+	 * @param inUrl URL to get
+	 * @param inFile file to save to
+	 */
+	private DiskTileCacher(URL inUrl, File inFile, ImageObserver inObserver)
+	{
+		_url = inUrl;
+		_file = inFile;
+		_observer = inObserver;
+	}
+
+	/**
+	 * Get the specified tile from the disk cache
+	 * @param inBasePath base path to whole disk cache
+	 * @param inTilePath relative path to requested tile
+	 * @return tile image if available, or null if not there
+	 */
+	public static MapTile getTile(String inBasePath, String inTilePath)
+	{
+		if (inBasePath == null) {return null;}
+		File tileFile = new File(inBasePath, inTilePath);
+		Image image = null;
+		if (tileFile.exists() && tileFile.canRead() && tileFile.length() > 0)
+		{
+			long fileStamp = tileFile.lastModified();
+			boolean isExpired = ((System.currentTimeMillis()-fileStamp) > CACHE_TIME_LIMIT);
+			try
+			{
+				image = Toolkit.getDefaultToolkit().createImage(tileFile.getAbsolutePath());
+				return new MapTile(image, isExpired);
+			}
+			catch (Exception e) {
+				System.err.println("createImage: " + e.getClass().getName() + " _ " + e.getMessage());
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Save the specified image tile to disk
+	 * @param inUrl url to get image from
+	 * @param inBasePath base path to disk cache
+	 * @param inTilePath relative path to this tile
+	 * @param inObserver observer to inform when load complete
+	 */
+	public static void saveTile(URL inUrl, String inBasePath, String inTilePath, ImageObserver inObserver)
+	{
+		if (inBasePath == null || inTilePath == null) {return;}
+		// save file if possible
+		File basePath = new File(inBasePath);
+		if (!basePath.exists() || !basePath.isDirectory() || !basePath.canWrite()) {
+			// Can't write to base path
+			return;
+		}
+		File tileFile = new File(basePath, inTilePath);
+		// Check if this file is already being loaded
+		if (isBeingLoaded(tileFile)) {return;}
+		// Check if it has already failed
+		if (BLOCKED_URLS.contains(inUrl.toString())) {return;}
+
+		File dir = tileFile.getParentFile();
+		// Start a new thread to load the image if necessary
+		if ((dir.exists() || dir.mkdirs()) && dir.canWrite())
+		{
+			new Thread(new DiskTileCacher(inUrl, tileFile, inObserver)).start();
+		}
+	}
+
+	/**
+	 * Check whether the given tile is already being loaded
+	 * @param inFile desired file
+	 * @return true if temporary file with this name exists
+	 */
+	private static boolean isBeingLoaded(File inFile)
+	{
+		File tempFile = new File(inFile.getAbsolutePath() + ".temp");
+		if (!tempFile.exists()) {
+			return false;
+		}
+		// File exists, so check if it was created recently
+		final long fileAge = System.currentTimeMillis() - tempFile.lastModified();
+		return fileAge < 1000000L; // overwrite if the temp file is still there after 1000s
+	}
+
+	/**
+	 * Run method for loading URL asynchronously and saving to file
+	 */
+	public void run()
+	{
+		boolean finished = false;
+		InputStream in = null;
+		FileOutputStream out = null;
+		File tempFile = new File(_file.getAbsolutePath() + ".temp");
+		// Use a synchronized block across all threads to make sure this url is only fetched once
+		synchronized (DiskTileCacher.class)
+		{
+			if (tempFile.exists()) {tempFile.delete();}
+			try {
+				if (!tempFile.createNewFile()) {return;}
+			}
+			catch (Exception e) {return;}
+		}
+		try
+		{
+			// Open streams from URL and to file
+			out = new FileOutputStream(tempFile);
+			//System.out.println("Opening URL: " + _url.toString());
+			// Set http user agent on connection
+			URLConnection conn = _url.openConnection();
+			conn.setRequestProperty("User-Agent", "GpsPrune v" + GpsPrune.VERSION_NUMBER);
+			in = conn.getInputStream();
+			int d = 0;
+			// Loop over each byte in the stream (maybe buffering is more efficient?)
+			while ((d = in.read()) >= 0) {
+				out.write(d);
+			}
+			finished = true;
+		} catch (IOException e) {
+			System.err.println("ioe: " + e.getClass().getName() + " - " + e.getMessage());
+			BLOCKED_URLS.add(_url.toString());
+		}
+		finally
+		{
+			// clean up files
+			try {in.close();} catch (Exception e) {} // ignore
+			try {out.close();} catch (Exception e) {} // ignore
+			if (!finished) {
+				tempFile.delete();
+			}
+		}
+		// Move temp file to desired file location
+		if (tempFile.exists() && !tempFile.renameTo(_file))
+		{
+			// File couldn't be moved - delete both to be sure
+			tempFile.delete();
+			_file.delete();
+		}
+		// Tell parent that load is finished (parameters ignored)
+		_observer.imageUpdate(null, ImageObserver.ALLBITS, 0, 0, 0, 0);
+	}
+}