Subclass java.io.InputStream via gen-class. Does not print progress yet, but does correctly download all search indices

project.clj

@@ -34,7 +34,7 @@
                    :offline (comp (partial not-any? identity)
                                   (juxt :online :disabled))}
   :source-paths ["leiningen-core/src" "src"]
-  :java-source-paths ["src/java"]
+  :aot [leiningen.extstream]
   ;; 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

@@ -1,90 +0,0 @@
-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/extstream.clj

@@ -0,0 +1,35 @@
+(ns leiningen.extstream
+  (:gen-class
+   :extends java.io.InputStream
+   :state state
+   :init init
+   :constructors {[java.io.InputStream Long] []}
+   :main false))
+
+(defn -init [stream content-length]
+  [ [] (ref (into {} {:stream stream
+                      :content-length content-length
+                      :total-bytes 0})) ])
+
+(defn print-progress [count length]
+  (let [progress (/ (* count 100.0) length)]
+    (printf "%.1f%%\r" progress)))
+
+(defn -read-void [this]
+  (let [b []
+        count (.read (:stream @(.state this)) b)]
+    (if (= -1 count) count (first b))))
+
+(defn -read-byte<> [this bytebuf]
+  (let [state-map (.state this)
+        stream (:stream @state-map)
+        content-length (:content-length @state-map)
+        count (.read stream bytebuf)]
+    count))
+
+(defn -read-byte<>-int-int [this bytebuf off len]
+  (let [state-map (.state this)
+        stream (:stream @state-map)
+        content-length (:content-length @state-map)
+        count (.read stream bytebuf off len)]
+    count))

src/leiningen/search.clj

@@ -15,7 +15,7 @@
            (org.apache.maven.index.updater IndexUpdater IndexUpdateRequest
                                            ResourceFetcher)
            (org.codehaus.plexus DefaultPlexusContainer PlexusContainer)
-           (leiningen ConsoleReportingInputStream)))
+           (leiningen extstream)))
 
 (defonce container (DefaultPlexusContainer.))
 
@@ -49,7 +49,7 @@
         (println "Downloading" (str @base-url "/" name))
         (let [r (http/get (str @base-url "/" name)
                                  {:throw-exceptions false :as :stream})
-              s (ConsoleReportingInputStream.
+              s (extstream.
                  (:body r)
                  (Long/parseLong (get (:headers r) "content-length")))]
           (deliver stream s)