Look for gitweb in /usr/share/gitweb

Debian based systems seem to install the gitweb CSS and logo
into /usr/share/gitweb.  So look for these files before the
older /var/www assumption when using the system supplied CGI.

Bug: issue 494
Change-Id: I03d470b3be095aaaa98ebf7ef66d5b29e712eb73
Signed-off-by: Shawn O. Pearce <sop@google.com>

Documentation/config-gitweb.txt

@@ -34,6 +34,17 @@ by Gerrit Code Review.  Site specific overrides can be placed in
 `'$site_path'/etc/gitweb_config.perl`, as this file is loaded as
 part of the generated configuration file.
 
+Logo and CSS
+~~~~~~~~~~~~
+
+If the package-manager installed CGI (`/usr/lib/cgi-bin/gitweb.cgi`)
+is being used, the stock CSS and logo files will be served from
+either `/usr/share/gitweb` or `/var/www`.
+
+Otherwise, Gerrit expects `gitweb.css` and `git-logo.png` to be found
+in the same directory as the CGI script itself.  This matches with
+the default source code distribution, and most custom installations.
+
 Access Control
 ~~~~~~~~~~~~~~
 

gerrit-httpd/src/main/java/com/google/gerrit/httpd/GitWebConfig.java

@@ -78,7 +78,10 @@ public class GitWebConfig {
       return;
     }
 
-    File cgi, css, logo;
+    final File pkgCgi = new File("/usr/lib/cgi-bin/gitweb.cgi");
+    String[] resourcePaths = {"/usr/share/gitweb", "/var/www"};
+    File cgi;
+
     if (cfgCgi != null) {
       // Use the CGI script configured by the administrator, failing if it
       // cannot be used as specified.
@@ -91,27 +94,32 @@ public class GitWebConfig {
         throw new IllegalStateException("Cannot execute gitweb.cgi: " + cgi);
       }
 
-      // Assume the administrator pointed us the distribution, which
-      // also has the corresponding CSS and logo file.
+      if (!cgi.equals(pkgCgi)) {
+        // Assume the administrator pointed us to the distribution,
+        // which also has the corresponding CSS and logo file.
+        //
+        resourcePaths = new String[] {cgi.getParentFile().getAbsolutePath()};
+      }
+
+    } else if (pkgCgi.isFile() && pkgCgi.canExecute()) {
+      // Use the OS packaged CGI.
       //
-      css = new File(cgi.getParentFile(), "gitweb.css");
-      logo = new File(cgi.getParentFile(), "git-logo.png");
+      log.debug("Assuming gitweb at " + pkgCgi);
+      cgi = pkgCgi;
 
     } else {
-      // Try to use the OS packaged CGI.
-      //
-      final File s = new File("/usr/lib/cgi-bin/gitweb.cgi");
-      if (s.isFile()) {
-        log.debug("Assuming gitweb at " + s);
-        cgi = s;
-        css = new File("/var/www/gitweb.css");
-        logo = new File("/var/www/git-logo.png");
+      log.warn("gitweb not installed (no " + pkgCgi + " found)");
+      cgi = null;
+      resourcePaths = new String[] {};
+    }
 
-      } else {
-        log.warn("gitweb not installed (no " + s + " found)");
-        cgi = null;
-        css = null;
-        logo = null;
+    File css = null, logo = null;
+    for (String path : resourcePaths) {
+      File dir = new File(path);
+      css = new File(dir, "gitweb.css");
+      logo = new File(dir, "git-logo.png");
+      if (css.isFile() && logo.isFile()) {
+        break;
       }
     }
 

gerrit-httpd/src/main/java/com/google/gerrit/httpd/gitweb/GitLogoServlet.java

@@ -51,9 +51,13 @@ class GitLogoServlet extends HttpServlet {
   @Inject
   GitLogoServlet(final GitWebConfig gitWebConfig) throws IOException {
     byte[] png;
-    try {
-      png = IO.readFully(gitWebConfig.getGitLogoPNG());
-    } catch (FileNotFoundException e) {
+    if (gitWebConfig.getGitLogoPNG() != null) {
+      try {
+        png = IO.readFully(gitWebConfig.getGitLogoPNG());
+      } catch (FileNotFoundException e) {
+        png = null;
+      }
+    } else {
       png = null;
     }
     raw = png;

gerrit-httpd/src/main/java/com/google/gerrit/httpd/gitweb/GitWebCssServlet.java

@@ -70,12 +70,17 @@ abstract class GitWebCssServlet extends HttpServlet {
 
   GitWebCssServlet(final File src, final GitWebConfig gitWebConfig)
       throws IOException {
-    final File dir = src.getParentFile();
-    final String name = src.getName();
-    final String raw = HtmlDomUtil.readFile(dir, name);
-    if (raw != null) {
-      raw_css = raw.getBytes(ENC);
-      gz_css = HtmlDomUtil.compress(raw_css);
+    if (src != null) {
+      final File dir = src.getParentFile();
+      final String name = src.getName();
+      final String raw = HtmlDomUtil.readFile(dir, name);
+      if (raw != null) {
+        raw_css = raw.getBytes(ENC);
+        gz_css = HtmlDomUtil.compress(raw_css);
+      } else {
+        raw_css = null;
+        gz_css = null;
+      }
     } else {
       raw_css = null;
       gz_css = null;