diff --git a/extras/Introjucer/Source/Application/jucer_CommandLine.cpp b/extras/Introjucer/Source/Application/jucer_CommandLine.cpp
index 05b6f5f819..2ce7a87697 100644
--- a/extras/Introjucer/Source/Application/jucer_CommandLine.cpp
+++ b/extras/Introjucer/Source/Application/jucer_CommandLine.cpp
@@ -130,7 +130,7 @@ namespace
         TemporaryFile temp (targetFile);
         ScopedPointer<FileOutputStream> out (temp.getFile().createOutputStream());
 
-        bool ok = out != nullptr && zip.writeToStream (*out);
+        bool ok = out != nullptr && zip.writeToStream (*out, nullptr);
         out = nullptr;
         ok = ok && temp.overwriteTargetFileWithTemporary();
 
diff --git a/modules/juce_core/streams/juce_FileInputSource.h b/modules/juce_core/streams/juce_FileInputSource.h
index 0b9459e415..35b1984dc9 100644
--- a/modules/juce_core/streams/juce_FileInputSource.h
+++ b/modules/juce_core/streams/juce_FileInputSource.h
@@ -40,7 +40,14 @@ class JUCE_API  FileInputSource     : public InputSource
 {
 public:
     //==============================================================================
+    /** Creates a FileInputSource for a file.
+        If the useFileTimeInHashGeneration parameter is true, then this object's
+        hashCode() method will incorporate the file time into its hash code; if
+        false, only the file name will be used for the hash.
+    */
     FileInputSource (const File& file, bool useFileTimeInHashGeneration = false);
+
+    /** Destructor. */
     ~FileInputSource();
 
     InputStream* createInputStream();
diff --git a/modules/juce_core/zip/juce_ZipFile.cpp b/modules/juce_core/zip/juce_ZipFile.cpp
index e3a179efd1..8affdc696e 100644
--- a/modules/juce_core/zip/juce_ZipFile.cpp
+++ b/modules/juce_core/zip/juce_ZipFile.cpp
@@ -541,18 +541,22 @@ void ZipFile::Builder::addFile (const File& fileToAdd, const int compressionLeve
     items.add (new Item (fileToAdd, compressionLevel, storedPathName));
 }
 
-bool ZipFile::Builder::writeToStream (OutputStream& target) const
+bool ZipFile::Builder::writeToStream (OutputStream& target, double* const progress) const
 {
     const int64 fileStart = target.getPosition();
 
-    int i;
-    for (i = 0; i < items.size(); ++i)
+    for (int i = 0; i < items.size(); ++i)
+    {
+        if (progress != nullptr)
+            *progress = (i + 0.5) / items.size();
+
         if (! items.getUnchecked (i)->writeData (target, fileStart))
             return false;
+    }
 
     const int64 directoryStart = target.getPosition();
 
-    for (i = 0; i < items.size(); ++i)
+    for (int i = 0; i < items.size(); ++i)
         if (! items.getUnchecked (i)->writeDirectoryEntry (target))
             return false;
 
@@ -567,5 +571,8 @@ bool ZipFile::Builder::writeToStream (OutputStream& target) const
     target.writeInt ((int) (directoryStart - fileStart));
     target.writeShort (0);
 
+    if (progress != nullptr)
+        *progress = 1.0;
+
     return true;
 }
diff --git a/modules/juce_core/zip/juce_ZipFile.h b/modules/juce_core/zip/juce_ZipFile.h
index b2156d2748..af65a2eaf6 100644
--- a/modules/juce_core/zip/juce_ZipFile.h
+++ b/modules/juce_core/zip/juce_ZipFile.h
@@ -43,7 +43,7 @@ class JUCE_API  ZipFile
 {
 public:
     /** Creates a ZipFile based for a file. */
-    ZipFile (const File& file);
+    explicit ZipFile (const File& file);
 
     //==============================================================================
     /** Creates a ZipFile for a given stream.
@@ -58,14 +58,14 @@ public:
         The stream will not be owned or deleted by this class - if you want the ZipFile to
         manage the stream's lifetime, use the other constructor.
     */
-    ZipFile (InputStream& inputStream);
+    explicit ZipFile (InputStream& inputStream);
 
     /** Creates a ZipFile for an input source.
 
         The inputSource object will be owned by the zip file, which will delete
         it later when not needed.
     */
-    ZipFile (InputSource* inputSource);
+    explicit ZipFile (InputSource* inputSource);
 
     /** Destructor. */
     ~ZipFile();
@@ -198,8 +198,11 @@ public:
         void addFile (const File& fileToAdd, int compressionLevel,
                       const String& storedPathName = String::empty);
 
-        /** Generates the zip file, writing it to the specified stream. */
-        bool writeToStream (OutputStream& target) const;
+        /** Generates the zip file, writing it to the specified stream.
+            If the progress parameter is non-null, it will be updated with an approximate
+            progress status between 0 and 1.0
+        */
+        bool writeToStream (OutputStream& target, double* progress) const;
 
         //==============================================================================
     private: