Implement search download progress reporting

project.clj

@@ -34,6 +34,7 @@
                    :offline (comp (partial not-any? identity)
                                   (juxt :online :disabled))}
   :source-paths ["leiningen-core/src" "src"]
+  :java-source-paths ["src/java"]
   ;; work around Clojure bug http://dev.clojure.org/jira/browse/CLJ-1034
   :uberjar-exclusions [#"^data_readers.clj$"]
   :eval-in :leiningen)

src/java/leiningen/ConsoleReportingInputStream.java

@@ -0,0 +1,90 @@
+package leiningen;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+/**
+ * Extends java.io.InputStream by reporting to console output
+ * the percentage of the stream that has been consumed after each
+ * read.  Employs a Decorator pattern so that the capabilities of
+ * the original InputStream subclass are preserved.
+ */
+
+public class ConsoleReportingInputStream extends InputStream
+{
+
+    private final long contentLength;
+    private final InputStream stream;
+    private long totalBytesRead=0;
+
+    /**
+     * @param stream - the InputStream to be wrapped by this object
+     * @param contentLength - the size, in bytes, of the content
+     * referred to by the stream parameter
+     */
+    public ConsoleReportingInputStream(InputStream stream, long contentLength)
+        throws IOException
+    {
+        if(stream == null) {
+            throw new IOException("InputStream cannot be null");
+        }
+
+        if(contentLength <= 0) {
+            throw new IOException("InputStream content-length must be greater than zero");
+        }
+         
+        this.stream = stream;
+        this.contentLength = contentLength;
+    }
+
+
+    private void updateAndReportProgress(int bytesRead) {
+        
+        totalBytesRead += bytesRead;
+        double progress = (totalBytesRead * 100.0)/contentLength;
+        // if progress < 100.0, then end output with carriage return
+        // otherwise, end output with newline.  This ensures that 
+        // progress will update on the same line until 100% reached
+        char lineTerm = '\r';
+        if(progress == 100.0) { lineTerm = '\n'; }
+
+        // Show one digit to the right of the decimal
+        System.out.printf("%.1f", progress);
+        System.out.print("% complete" + lineTerm);        
+    }
+
+    
+    @Override
+    public int read() throws IOException
+    {
+        byte[] buf = new byte[1];
+        int cnt = stream.read(buf);
+
+        if(cnt == -1) { return cnt; }
+        else { 
+            updateAndReportProgress(cnt);
+            return buf[0];
+        }
+             
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException
+    {
+        int cnt = stream.read(b);
+        if(cnt >= 0) {
+            updateAndReportProgress(cnt);
+        }
+        return cnt;
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException
+    {
+        int cnt = stream.read(b, off, len);
+        if(cnt >= 0) {
+            updateAndReportProgress(cnt);
+        }        
+        return cnt;
+    }
+}

src/leiningen/search.clj

@@ -14,7 +14,8 @@
            (org.apache.maven.index.expr UserInputSearchExpression)
            (org.apache.maven.index.updater IndexUpdater IndexUpdateRequest
                                            ResourceFetcher)
-           (org.codehaus.plexus DefaultPlexusContainer PlexusContainer)))
+           (org.codehaus.plexus DefaultPlexusContainer PlexusContainer)
+           (leiningen ConsoleReportingInputStream)))
 
 (defonce container (DefaultPlexusContainer.))
 
@@ -34,7 +35,7 @@
 (defn- remove-context [context]
   (.removeIndexingContext indexer context false))
 
-;; TODO: add progress reporting back in
+
 (defn- http-resource-fetcher []
   (let [base-url (promise)
         stream (promise)]
@@ -45,9 +46,12 @@
       (disconnect []
         (.close @stream))
       (^java.io.InputStream retrieve [name]
-        (main/debug "Downloading" (str @base-url "/" name))
-        (let [s (:body (http/get (str @base-url "/" name)
-                                 {:throw-exceptions false :as :stream}))]
+        (println "Downloading" (str @base-url "/" name))
+        (let [r (http/get (str @base-url "/" name)
+                                 {:throw-exceptions false :as :stream})
+              s (ConsoleReportingInputStream.
+                 (:body r)
+                 (Long/parseLong (get (:headers r) "content-length")))]
           (deliver stream s)
           s)))))