1 files changed, 179 insertions, 0 deletions
diff --git a/lib/osx_file_icon.mm b/lib/osx_file_icon.mm
new file mode 100644
index 00000000..6a068998
--- /dev/null
+++ b/lib/osx_file_icon.mm
@@ -0,0 +1,179 @@
+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved        *
+// **************************************************************************
+
+#include "osx_file_icon.h"
+#include <zen/osx_throw_exception.h>
+#include <zen/scope_guard.h>
+#include <zen/basic_math.h>
+
+namespace
+{
+osx::ImageData extractBytes(NSImage* nsImg, int requestedSize) //throw OsxError; NSException?
+{
+    /*
+	wxBitmap(NSImage*) is not good enough: it calls "[NSBitmapImageRep imageRepWithData:[img TIFFRepresentation]]"
+		=> inefficient: TIFFRepresentation converts all contained images of an NSImage
+		=> lacking: imageRepWithData extracts the first contained image only!
+		=> wxBitmap(NSImage*) is wxCocoa only, deprecated!
+		=> wxWidgets generally is not thread-safe so care must be taken to use wxBitmap from main thread only! (e.g. race-condition on non-atomic ref-count!!!)
+		
+	-> we need only a single bitmap at a specific size => extract raw bytes for use with wxImage in a thread-safe way!
+	*/
+
+    //we choose the Core Graphics solution; for the equivalent App-Kit way see: http://www.cocoabuilder.com/archive/cocoa/193131-is-lockfocus-main-thread-specific.html#193191
+
+    ZEN_OSX_ASSERT(requestedSize > 0);
+    NSRect rectProposed = NSMakeRect(0, 0, requestedSize, requestedSize); //this is merely a hint!
+
+	CGImageRef imgRef = [nsImg CGImageForProposedRect:&rectProposed context:nil hints:nil];
+    ZEN_OSX_ASSERT(imgRef != NULL); //can this fail? not documented; ownership?? not documented!
+
+    const size_t width  = CGImageGetWidth (imgRef);
+    const size_t height = CGImageGetHeight(imgRef);
+
+    ZEN_OSX_ASSERT(width > 0 && height > 0 && requestedSize > 0);
+
+    int trgWidth  = width;
+    int trgHeight = height;
+
+    const int maxExtent = std::max(width, height); //don't stretch small images, but shrink large ones instead!
+    if (requestedSize < maxExtent)
+    {
+        trgWidth  = width  * requestedSize / maxExtent;
+        trgHeight = height * requestedSize / maxExtent;
+    }
+
+    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+    ZEN_OSX_ASSERT(colorSpace != NULL); //may fail
+    ZEN_ON_SCOPE_EXIT(CGColorSpaceRelease(colorSpace));
+
+    std::vector<unsigned char> buf(trgWidth* trgHeight * 4); //32-bit ARGB, little endian byte order -> already initialized with 0 = fully transparent
+
+    //supported color spaces: https://developer.apple.com/library/mac/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_context/dq_context.html#//apple_ref/doc/uid/TP30001066-CH203-BCIBHHBB
+    CGContextRef ctxRef = CGBitmapContextCreate(&buf[0],      //void *data,
+                                                trgWidth,     //size_t width,
+                                                trgHeight,    //size_t height,
+                                                8,            //size_t bitsPerComponent,
+                                                4 * trgWidth, //size_t bytesPerRow,
+                                                colorSpace,   //CGColorSpaceRef colorspace,
+                                                kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little); //CGBitmapInfo bitmapInfo
+    ZEN_OSX_ASSERT(ctxRef != NULL);
+    ZEN_ON_SCOPE_EXIT(CGContextRelease(ctxRef));
+
+    CGContextDrawImage(ctxRef, CGRectMake(0, 0, trgWidth, trgHeight), imgRef); //can this fail?  not documented
+
+    //CGContextFlush(ctxRef); //"If you pass [...] a bitmap context, this function does nothing."
+
+    osx::ImageData imgOut(trgWidth, trgHeight);
+
+    auto it = buf.begin();
+    auto itOutRgb = imgOut.rgb.begin();
+    auto itOutAlpha = imgOut.alpha.begin();
+    for (int i = 0; i < trgWidth * trgHeight; ++i)
+    {
+        const unsigned char b = *it++;
+        const unsigned char g = *it++;
+        const unsigned char r = *it++;
+        const unsigned char a = *it++;
+
+        //unsigned arithmetics caveat!
+        auto demultiplex = [&](unsigned char c) { return static_cast<unsigned char>(numeric::confineCpy(a == 0 ? 0 : (c * 255 + a - 1) / a, 0, 255)); }; //=ceil(c * 255 / a)
+
+        *itOutRgb++ = demultiplex(r);
+        *itOutRgb++ = demultiplex(g);
+        *itOutRgb++ = demultiplex(b);
+        *itOutAlpha++ = a;
+    }
+
+    return imgOut;
+}
+}
+
+
+osx::ImageData osx::getThumbnail(const char* filename, int requestedSize) //throw OsxError
+{
+    @try
+    {
+        @autoreleasepool
+        {
+			NSString* nsFile = [NSString stringWithCString:filename encoding:NSUTF8StringEncoding];
+            ZEN_OSX_ASSERT(nsFile != nil); //throw OsxError; can this fail?  not documented
+            //stringWithCString returns string which is already set to autorelease!
+
+			NSImage* nsImg = [[[NSImage alloc] initWithContentsOfFile:nsFile] autorelease];
+            ZEN_OSX_ASSERT(nsImg != nil); //may fail
+
+            return extractBytes(nsImg, requestedSize); //throw OsxError
+        }
+    }
+    @catch (NSException* e)
+    {
+        throwOsxError(e); //throw OsxError
+    }
+}
+
+
+osx::ImageData osx::getFileIcon(const char* filename, int requestedSize) //throw OsxError
+{
+    @try
+    {
+        @autoreleasepool
+        {
+			NSString* nsFile = [NSString stringWithCString:filename encoding:NSUTF8StringEncoding];
+            ZEN_OSX_ASSERT(nsFile != nil); //throw OsxError; can this fail?  not documented
+            //stringWithCString returns string which is already set to autorelease!
+
+			NSImage* nsImg = [[NSWorkspace sharedWorkspace] iconForFile:nsFile];
+            ZEN_OSX_ASSERT(nsImg != nil); //can this fail?  not documented
+
+            return extractBytes(nsImg, requestedSize); //throw OsxError
+        }
+    }
+    @catch (NSException* e)
+    {
+        throwOsxError(e); //throw OsxError
+    }
+}
+
+
+osx::ImageData osx::getDefaultFileIcon(int requestedSize) //throw OsxError
+{
+    @try
+    {
+        @autoreleasepool
+        {
+			NSImage* nsImg = [[NSWorkspace sharedWorkspace] iconForFileType:NSFileTypeForHFSTypeCode(kGenericDocumentIcon)];
+            //NSImage* nsImg = [[NSWorkspace sharedWorkspace] iconForFileType:@"dat"];
+            ZEN_OSX_ASSERT(nsImg != nil); //can this fail?  not documented
+
+            return extractBytes(nsImg, requestedSize); //throw OsxError
+        }
+    }
+    @catch (NSException* e)
+    {
+        throwOsxError(e); //throw OsxError
+    }
+}
+
+
+osx::ImageData osx::getDefaultFolderIcon(int requestedSize) //throw OsxError
+{
+    @try
+    {
+        @autoreleasepool
+        {
+			NSImage* nsImg = [NSImage imageNamed:NSImageNameFolder];
+            //NSImage* nsImg = [[NSWorkspace sharedWorkspace] iconForFileType:NSFileTypeForHFSTypeCode(kGenericFolderIcon)];
+            ZEN_OSX_ASSERT(nsImg != nil); //may fail
+
+            return extractBytes(nsImg, requestedSize); //throw OsxError
+        }
+    }
+    @catch (NSException* e)
+    {
+        throwOsxError(e); //throw OsxError
+    }
+}