Tidied up some comments and usage of File::createOutputStream() and createInputStream()

examples/Audio/AudioRecordingDemo.h

@@ -78,15 +78,13 @@ public:
         {
             // Create an OutputStream to write to our destination file...
             file.deleteFile();
-            std::unique_ptr<FileOutputStream> fileStream (file.createOutputStream());
 
-            if (fileStream.get() != nullptr)
+            if (auto fileStream = std::unique_ptr<FileOutputStream> (file.createOutputStream()))
             {
                 // Now create a WAV writer object that writes to our output stream...
                 WavAudioFormat wavFormat;
-                auto* writer = wavFormat.createWriterFor (fileStream.get(), sampleRate, 1, 16, {}, 0);
 
-                if (writer != nullptr)
+                if (auto writer = wavFormat.createWriterFor (fileStream.get(), sampleRate, 1, 16, {}, 0))
                 {
                     fileStream.release(); // (passes responsibility for deleting the stream to the writer object that is now using it)
 

examples/GUI/CameraDemo.h

@@ -340,25 +340,25 @@ private:
        #if JUCE_ANDROID || JUCE_IOS
         auto imageFile = File::getSpecialLocation (File::tempDirectory).getNonexistentChildFile ("JuceCameraPhotoDemo", ".jpg");
 
-        if (auto stream = std::unique_ptr<OutputStream> (imageFile.createOutputStream()))
+        FileOutputStream stream (imageFile);
+
+        if (stream.openedOk()
+             && JPEGImageFormat().writeImageToStream (image, stream))
         {
-            if (JPEGImageFormat().writeImageToStream (image, *stream))
-            {
-                URL url (imageFile);
+            URL url (imageFile);
 
-                snapshotButton   .setEnabled (false);
-                recordMovieButton.setEnabled (false);
-                contentSharingPending = true;
+            snapshotButton   .setEnabled (false);
+            recordMovieButton.setEnabled (false);
+            contentSharingPending = true;
 
-                SafePointer<CameraDemo> safeThis (this);
+            SafePointer<CameraDemo> safeThis (this);
 
-                juce::ContentSharer::getInstance()->shareFiles ({url},
-                                                                [safeThis] (bool success, const String&) mutable
-                                                                {
-                                                                    if (safeThis)
-                                                                        safeThis->sharingFinished (success, true);
-                                                                });
-            }
+            juce::ContentSharer::getInstance()->shareFiles ({url},
+                                                            [safeThis] (bool success, const String&) mutable
+                                                            {
+                                                                if (safeThis)
+                                                                    safeThis->sharingFinished (success, true);
+                                                            });
         }
        #endif
     }

examples/GUI/DialogsDemo.h

@@ -335,9 +335,11 @@ private:
                     fileToSave = fileToSave.getChildFile ("JUCE.png");
                     fileToSave.deleteFile();
 
-                    std::unique_ptr<OutputStream> outStream (fileToSave.createOutputStream());
-                    std::unique_ptr<InputStream> inStream (createAssetInputStream ("juce_icon.png"));
-                    outStream->writeFromInputStream (*inStream, -1);
+                    FileOutputStream outStream (fileToSave);
+
+                    if (outStream.openedOk())
+                        if (auto inStream = std::unique_ptr<InputStream> (createAssetInputStream ("juce_icon.png")))
+                            outStream.writeFromInputStream (*inStream, -1);
                 }
 
                 fc.reset (new FileChooser ("Choose a file to save...",

examples/Utilities/NetworkingDemo.h

@@ -103,15 +103,16 @@ public:
         StringPairArray responseHeaders;
         int statusCode = 0;
 
-        std::unique_ptr<InputStream> stream (url.createInputStream (false, nullptr, nullptr, {},
-                                                                    10000, // timeout in millisecs
-                                                                    &responseHeaders, &statusCode));
-        if (stream.get() != nullptr)
+        if (auto stream = std::unique_ptr<InputStream> (url.createInputStream (false, nullptr, nullptr, {},
+                                                                               10000, // timeout in millisecs
+                                                                               &responseHeaders, &statusCode)))
+        {
             return (statusCode != 0 ? "Status code: " + String (statusCode) + newLine : String())
                     + "Response headers: " + newLine
                     + responseHeaders.getDescription() + newLine
                     + "----------------------------------------------------" + newLine
                     + stream->readEntireStreamAsString();
+        }
 
         if (statusCode != 0)
             return "Failed to connect, status code = " + String (statusCode);

extras/Projucer/Source/Application/jucer_CommandLine.cpp

@@ -279,13 +279,15 @@ namespace
         std::cout << "Writing: " << targetFile.getFullPathName() << std::endl;
 
         TemporaryFile temp (targetFile);
-        std::unique_ptr<FileOutputStream> out (temp.getFile().createOutputStream());
 
-        bool ok = out != nullptr && zip.writeToStream (*out, nullptr);
-        out.reset();
-        ok = ok && temp.overwriteTargetFileWithTemporary();
+        {
+            FileOutputStream out (temp.getFile());
+
+            if (! (out.openedOk() && zip.writeToStream (out, nullptr)))
+                ConsoleApplication::fail ("Failed to write to the target file: " + targetFile.getFullPathName());
+        }
 
-        if (! ok)
+        if (! temp.overwriteTargetFileWithTemporary())
             ConsoleApplication::fail ("Failed to write to the target file: " + targetFile.getFullPathName());
     }
 

extras/Projucer/Source/CodeEditor/jucer_ItemPreviewComponent.h

@@ -82,33 +82,29 @@ private:
         facts.add (file.getFullPathName());
         drawable.reset();
 
+        if (auto input = std::unique_ptr<FileInputStream> (file.createInputStream()))
         {
-            std::unique_ptr<InputStream> input (file.createInputStream());
+            auto totalSize = input->getTotalLength();
+            String formatName;
 
-            if (input != nullptr)
-            {
-                auto totalSize = input->getTotalLength();
-                String formatName;
-
-                if (auto* format = ImageFileFormat::findImageFormatForStream (*input))
-                    formatName = " " + format->getFormatName();
-
-                input.reset();
+            if (auto* format = ImageFileFormat::findImageFormatForStream (*input))
+                formatName = " " + format->getFormatName();
 
-                auto image = ImageCache::getFromFile (file);
+            input.reset();
 
-                if (image.isValid())
-                {
-                    auto* d = new DrawableImage();
-                    d->setImage (image);
-                    drawable.reset (d);
+            auto image = ImageCache::getFromFile (file);
 
-                    facts.add (String (image.getWidth()) + " x " + String (image.getHeight()) + formatName);
-                }
+            if (image.isValid())
+            {
+                auto* d = new DrawableImage();
+                d->setImage (image);
+                drawable.reset (d);
 
-                if (totalSize > 0)
-                    facts.add (File::descriptionOfSizeInBytes (totalSize));
+                facts.add (String (image.getWidth()) + " x " + String (image.getHeight()) + formatName);
             }
+
+            if (totalSize > 0)
+                facts.add (File::descriptionOfSizeInBytes (totalSize));
         }
 
         if (drawable == nullptr)

modules/juce_audio_formats/codecs/juce_OggVorbisAudioFormat.cpp

@@ -486,9 +486,7 @@ int OggVorbisAudioFormat::estimateOggFileQuality (const File& source)
 {
     if (auto* in = source.createInputStream())
     {
-        std::unique_ptr<AudioFormatReader> r (createReaderFor (in, true));
-
-        if (r != nullptr)
+        if (auto r = std::unique_ptr<AudioFormatReader> (createReaderFor (in, true)))
         {
             auto lengthSecs = r->lengthInSamples / r->sampleRate;
             auto approxBitsPerSecond = (int) (source.getSize() * 8 / lengthSecs);

modules/juce_core/files/juce_File.h

@@ -607,6 +607,17 @@ public:
     //==============================================================================
     /** Creates a stream to read from this file.
 
+        Note that this is an old method, and actually it's usually best to avoid it and
+        instead use an RAII pattern with an FileInputStream directly, e.g.
+        @code
+        FileInputStream input (fileToOpen);
+
+        if (input.openedOk())
+        {
+            input.read (etc...
+        }
+        @endcode
+
         @returns    a stream that will read from this file (initially positioned at the
                     start of the file), or nullptr if the file can't be opened for some reason
         @see createOutputStream, loadFileAsData
@@ -615,13 +626,28 @@ public:
 
     /** Creates a stream to write to this file.
 
+        Note that this is an old method, and actually it's usually best to avoid it and
+        instead use an RAII pattern with an FileOutputStream directly, e.g.
+        @code
+        FileOutputStream output (fileToOpen);
+
+        if (output.openedOk())
+        {
+            output.read etc...
+        }
+        @endcode
+
         If the file exists, the stream that is returned will be positioned ready for
         writing at the end of the file. If you want to write to the start of the file,
         replacing the existing content, then you can do the following:
         @code
-        auto* stream = file.createOutputStream();
-        stream->setPosition (0);
-        stream->truncate();
+        FileOutputStream output (fileToOverwrite);
+
+        if (output.openedOk())
+        {
+            output.setPosition (0);
+            output.truncate();
+            ...
         @endcode
 
         @returns    a stream that will write to this file (initially positioned at the

modules/juce_core/files/juce_FileOutputStream.h

@@ -42,9 +42,19 @@ public:
         does not exist), the failedToOpen() method will return true.
 
         If the file already exists when opened, the stream's write-position will
-        be set to the end of the file. To overwrite an existing file,
-        use File::deleteFile() before opening the stream, or use setPosition(0)
-        after it's opened (although this won't truncate the file).
+        be set to the end of the file. To overwrite an existing file, you can truncate
+        it like this:
+
+        @code
+        FileOutputStream stream (file);
+
+        if (stream.openedOk())
+        {
+            stream.setPosition (0);
+            stream.truncate();
+            ...
+        @endcode
+
 
         Destroying a FileOutputStream object does not force the operating system
         to write the buffered data to disk immediately. If this is required you

modules/juce_core/files/juce_TemporaryFile.h

@@ -41,12 +41,10 @@ namespace juce
         TemporaryFile temp (myTargetFile);
 
         // create a stream to the temporary file, and write some data to it...
-        std::unique_ptr<FileOutputStream> out (temp.getFile().createOutputStream());
-
-        if (out != nullptr)
+        if (auto out = std::unique_ptr<FileOutputStream> (temp.getFile().createOutputStream()))
         {
             out->write ( ...etc )
-            out = nullptr; // (deletes the stream)
+            out.reset(); // (deletes the stream)
 
             // ..now we've finished writing, this will rename the temp file to
             // make it replace the target file we specified above.

modules/juce_core/network/juce_URL.cpp

@@ -118,9 +118,7 @@ URL::DownloadTask* URL::DownloadTask::createFallbackDownloader (const URL& urlTo
     const size_t bufferSize = 0x8000;
     targetFileToUse.deleteFile();
 
-    std::unique_ptr<FileOutputStream> outputStream (targetFileToUse.createOutputStream (bufferSize));
-
-    if (outputStream != nullptr)
+    if (auto outputStream = std::unique_ptr<FileOutputStream> (targetFileToUse.createOutputStream (bufferSize)))
     {
         std::unique_ptr<WebInputStream> stream (new WebInputStream (urlToUse, usePostRequest));
         stream->withExtraHeaders (extraHeadersToUse);

modules/juce_gui_basics/filebrowser/juce_ContentSharer.cpp

@@ -111,9 +111,7 @@ private:
 
         if (tempFile.create().wasOk())
         {
-            std::unique_ptr<FileOutputStream> outputStream (tempFile.createOutputStream());
-
-            if (outputStream != nullptr)
+            if (auto outputStream = std::unique_ptr<FileOutputStream> (tempFile.createOutputStream()))
             {
                 size_t pos = 0;
                 size_t totalSize = data.getSize();

modules/juce_gui_basics/filebrowser/juce_ImagePreviewComponent.cpp

@@ -38,12 +38,12 @@ ImagePreviewComponent::~ImagePreviewComponent()
 //==============================================================================
 void ImagePreviewComponent::getThumbSize (int& w, int& h) const
 {
-    const int availableW = proportionOfWidth (0.97f);
-    const int availableH = getHeight() - 13 * 4;
+    auto availableW = proportionOfWidth (0.97f);
+    auto availableH = getHeight() - 13 * 4;
 
-    const double scale = jmin (1.0,
-                               availableW / (double) w,
-                               availableH / (double) h);
+    auto scale = jmin (1.0,
+                       availableW / (double) w,
+                       availableH / (double) h);
 
     w = roundToInt (scale * w);
     h = roundToInt (scale * h);
@@ -66,18 +66,18 @@ void ImagePreviewComponent::timerCallback()
     currentDetails.clear();
     repaint();
 
-    std::unique_ptr<FileInputStream> in (fileToLoad.createInputStream());
+    FileInputStream in (fileToLoad);
 
-    if (in != nullptr && in->getFile().existsAsFile())
+    if (in.openedOk() && fileToLoad.existsAsFile())
     {
-        if (ImageFileFormat* const format = ImageFileFormat::findImageFormatForStream (*in))
+        if (auto format = ImageFileFormat::findImageFormatForStream (in))
         {
-            currentThumbnail = format->decodeImage (*in);
+            currentThumbnail = format->decodeImage (in);
 
             if (currentThumbnail.isValid())
             {
-                int w = currentThumbnail.getWidth();
-                int h = currentThumbnail.getHeight();
+                auto w = currentThumbnail.getWidth();
+                auto h = currentThumbnail.getHeight();
 
                 currentDetails
                     << fileToLoad.getFileName() << "\n"
@@ -99,13 +99,13 @@ void ImagePreviewComponent::paint (Graphics& g)
     {
         g.setFont (13.0f);
 
-        int w = currentThumbnail.getWidth();
-        int h = currentThumbnail.getHeight();
+        auto w = currentThumbnail.getWidth();
+        auto h = currentThumbnail.getHeight();
         getThumbSize (w, h);
 
         const int numLines = 4;
-        const int totalH = 13 * numLines + h + 4;
-        const int y = (getHeight() - totalH) / 2;
+        auto totalH = 13 * numLines + h + 4;
+        auto y = (getHeight() - totalH) / 2;
 
         g.drawImageWithin (currentThumbnail,
                            (getWidth() - w) / 2, y, w, h,