Improve error msg for ebook generation

1 files changed, 20 insertions, 1 deletions

diff --git a/lib/utils/command.js b/lib/utils/command.js
index 49b0998..c1689cb 100644
--- a/lib/utils/command.js
+++ b/lib/utils/command.js
@@ -11,7 +11,26 @@ function exec(command, options) {
         return Promise.reject(new Error('Command execution is not possible on this platform'));
     }
 
-    return Promise.nfcall(childProcess.exec, command, options);
+    var d = Promise.defer();
+
+    var child = childProcess.exec(command, options, function(err, stdout, stderr) {
+        if (!err) {
+            d.resolve();
+        }
+
+        err.message = stdout.toString('utf8') + stderr.toString('utf8');
+        d.reject(err);
+    });
+
+    child.stdout.on('data', function (data) {
+        d.notify(data);
+    });
+
+    child.stderr.on('data', function (data) {
+        d.notify(data);
+    });
+
+    return d.promise;
 }
 
 // Spawn an executable