1 files changed, 298 insertions, 0 deletions
diff --git a/library/iconBuffer.cpp b/library/iconBuffer.cpp
new file mode 100644
index 00000000..a969f689
--- /dev/null
+++ b/library/iconBuffer.cpp
@@ -0,0 +1,298 @@
+#include "iconBuffer.h"
+#include <wx/thread.h>
+#include "globalFunctions.h"
+#include <wx/utils.h>
+#include <wx/bitmap.h>
+#include <wx/msw/wrapwin.h> //includes "windows.h"
+#include <wx/msgdlg.h>
+#include "../algorithm.h"
+#include <wx/icon.h>
+#include <map>
+#include <queue>
+
+using FreeFileSync::IconBuffer;
+
+
+class BasicString //simple thread safe string class
+{
+public:
+    BasicString()
+    {
+        data = new DefaultChar[1]; //compliance with delete []
+        *data = 0;                 //compliance with c_str()
+    }
+
+    BasicString(const Zstring& other) //make DEEP COPY from Zstring!
+    {
+        data = new DefaultChar[other.length() + 1];
+        memcpy(data, other.c_str(), (other.length() + 1) * sizeof(DefaultChar));
+    }
+
+    BasicString(const BasicString& other)
+    {
+        const size_t otherLen = defaultLength(other.c_str());
+        data = new DefaultChar[otherLen + 1];
+        memcpy(data, other.c_str(), (otherLen + 1) * sizeof(DefaultChar));
+    }
+
+    ~BasicString()
+    {
+        delete [] data;
+    }
+
+    BasicString& operator=(const BasicString& other)
+    {   //exception safety; handle self-assignment implicitly
+        const size_t otherLen = defaultLength(other.c_str());
+        DefaultChar* dataNew = new DefaultChar[otherLen + 1];
+        memcpy(dataNew, other.c_str(), (otherLen + 1) * sizeof(DefaultChar));
+
+        delete data;
+        data = dataNew;
+
+        return *this;
+    }
+
+    const DefaultChar* c_str() const
+    {
+        return data;
+    }
+
+private:
+    DefaultChar* data;
+};
+
+
+class WorkerThread : public wxThread
+{
+public:
+    WorkerThread(IconBuffer* iconBuff);
+
+    void setWorkload(const std::vector<Zstring>& load); //(re-)set new workload of icons to be retrieved
+    void quitThread();
+
+    virtual ExitCode Entry();
+
+private:
+    void doWork();
+
+//---------------------- Shared Data -------------------------
+    typedef BasicString FileName;
+
+    wxCriticalSection lockWorkload; //use for locking shared data
+    std::vector<FileName> workload; //processes last elements of vector first!
+    bool threadHasMutex;
+    bool threadExitIsRequested;
+//------------------------------------------------------------
+
+    //event: icon buffer -> woker thread
+    wxMutex threadIsListening;
+    wxCondition continueWork; //wake up thread
+
+    IconBuffer* iconBuffer;
+};
+
+
+WorkerThread::WorkerThread(IconBuffer* iconBuff) :
+        wxThread(wxTHREAD_JOINABLE),
+        threadHasMutex(false),
+        threadExitIsRequested(false),
+        threadIsListening(),
+        continueWork(threadIsListening),
+        iconBuffer(iconBuff)
+{
+    if (Create() != wxTHREAD_NO_ERROR)
+        throw RuntimeException(wxString(wxT("Error creating icon buffer worker thread!")));
+
+    if (Run() != wxTHREAD_NO_ERROR)
+        throw RuntimeException(wxString(wxT("Error starting icon buffer worker thread!")));
+
+    //wait until thread has aquired mutex
+    bool hasMutex = false;
+    while (!hasMutex)
+    {
+        wxMilliSleep(5);
+        wxCriticalSectionLocker dummy(lockWorkload);
+        hasMutex = threadHasMutex;
+    }   //polling -> it's not nice, but works and is no issue
+}
+
+
+void WorkerThread::setWorkload(const std::vector<Zstring>& load) //(re-)set new workload of icons to be retrieved
+{
+    wxCriticalSectionLocker dummy(lockWorkload);
+
+    workload.clear();
+    for (std::vector<Zstring>::const_iterator i = load.begin(); i != load.end(); ++i)
+        workload.push_back(*i); //make DEEP COPY from Zstring!
+
+    if (!workload.empty())
+        continueWork.Signal(); //wake thread IF he is waiting
+}
+
+
+void WorkerThread::quitThread()
+{
+    wxMutexLocker dummy(threadIsListening); //wait until thread is in waiting state
+    threadExitIsRequested = true; //no sharing conflicts in this situation
+    continueWork.Signal(); //exit thread
+}
+
+
+wxThread::ExitCode WorkerThread::Entry()
+{
+    try
+    {
+        wxMutexLocker dummy(threadIsListening); //this lock needs to be called from WITHIN the thread => calling it from constructor(Main thread) would be useless
+        {                                       //this mutex STAYS locked all the time except of continueWork.Wait()!
+            wxCriticalSectionLocker dummy(lockWorkload);
+            threadHasMutex = true;
+        }
+
+        while (true)
+        {
+            continueWork.Wait(); //waiting for continueWork.Signal(); unlocks Mutex "threadIsListening"
+
+            //no mutex needed in this context
+            if (threadExitIsRequested) //no mutex here: atomicity is not prob for a bool, but visibility (e.g. caching in registers)
+                return 0;              //shouldn't be a problem nevertheless because of implicit memory barrier caused by mutex.Lock() in .Wait()
+
+            //do work: get the file icon.
+            doWork();
+        }
+    }
+    catch (RuntimeException& e) //exceptions must be catched per thread
+    {
+        wxMessageBox(e.show());
+        return 0;
+    }
+}
+
+
+void WorkerThread::doWork()
+{
+    BasicString fileName; //don't use Zstring: reference-counted objects are NOT THREADSAFE!!! e.g. double deletion might happen
+
+    //do work: get the file icon.
+    while (true)
+    {
+        {
+            wxCriticalSectionLocker dummy(lockWorkload);
+            if (workload.empty())
+                break; //enter waiting state
+            fileName = workload.back();
+            workload.pop_back();
+        }
+
+        if (iconBuffer->requestIcon(Zstring(fileName.c_str()))) //thread safety: Zstring okay, won't be reference-counted in requestIcon()
+            break; //icon already in buffer: enter waiting state
+
+        //load icon
+        SHFILEINFO fileInfo;
+        fileInfo.hIcon = 0; //initialize hIcon
+
+        if (SHGetFileInfo(fileName.c_str(), //NOTE: CoInitializeEx()/CoUninitialize() implicitly called by wxWidgets on program startup!
+                          0,
+                          &fileInfo,
+                          sizeof(fileInfo),
+                          SHGFI_ICON | SHGFI_SMALLICON) &&
+
+                fileInfo.hIcon != 0) //fix for weird error: SHGetFileInfo() might return successfully WITHOUT filling fileInfo.hIcon!!
+        {                        //bug report: https://sourceforge.net/tracker/?func=detail&aid=2768004&group_id=234430&atid=1093080
+
+            wxIcon newIcon; //attention: wxIcon uses reference counting!
+            newIcon.SetHICON(fileInfo.hIcon);
+            newIcon.SetSize(IconBuffer::ICON_SIZE, IconBuffer::ICON_SIZE);
+
+            iconBuffer->insertIntoBuffer(fileName.c_str(), newIcon); //thread safety: icon may be deleted only within insertIntoBuffer()
+
+            //freeing of icon handle seems to happen somewhere beyond wxIcon destructor
+            //if (!DestroyIcon(fileInfo.hIcon))
+            //  throw RuntimeException(wxString(wxT("Error deallocating Icon handle!\n\n")) + FreeFileSync::getLastErrorFormatted());
+
+        }
+        else
+        {
+            //if loading of icon fails for whatever reason, just save a dummy icon to avoid re-loading
+            iconBuffer->insertIntoBuffer(fileName.c_str(), wxNullIcon);
+        }
+    }
+}
+
+//---------------------------------------------------------------------------------------------------
+
+typedef Zstring FileName;
+class IconDB : public std::map<FileName, wxIcon> {};
+class IconDbSequence : public std::queue<FileName> {};
+
+//---------------------------------------------------------------------------------------------------
+
+
+IconBuffer& IconBuffer::getInstance()
+{
+    static IconBuffer instance;
+    return instance;
+}
+
+
+IconBuffer::IconBuffer() :
+        lockIconDB( new wxCriticalSection),
+        buffer(     new IconDB),
+        bufSequence(new IconDbSequence),
+        worker(     new WorkerThread(this)) //might throw exceptions!
+{}
+
+
+IconBuffer::~IconBuffer()
+{
+    worker->quitThread();
+    worker->Wait(); //wait until thread has exitted
+}
+
+
+bool IconBuffer::requestIcon(const Zstring& fileName, wxIcon* icon)
+{
+    wxCriticalSectionLocker dummy(*lockIconDB);
+    IconDB::const_iterator i = buffer->find(fileName);
+
+    if (i != buffer->end())
+    {
+        if (icon != NULL)
+            *icon = i->second;
+        return true;
+    }
+
+    return false;
+}
+
+
+void IconBuffer::setWorkload(const std::vector<Zstring>& load)
+{
+    worker->setWorkload(load);
+}
+
+
+void IconBuffer::insertIntoBuffer(const DefaultChar* fileName, const wxIcon& icon) //called by worker thread
+{
+    if (icon.IsOk()) //this check won't hurt
+    {
+        wxCriticalSectionLocker dummy(*lockIconDB);
+
+        const Zstring fileNameZ = fileName;
+
+        const std::pair<IconDB::iterator, bool> rc = buffer->insert(IconDB::value_type(fileNameZ, icon));
+
+        if (rc.second) //if insertion took place
+            bufSequence->push(fileNameZ);
+
+        assert(buffer->size() == bufSequence->size());
+
+        //remove elements if buffer becomes too big:
+        if (buffer->size() > 1000) //limit buffer size: critical because large buffers seem to cause various wxIcon/wxBitmap issues!
+        {
+            //remove oldest element
+            buffer->erase(bufSequence->front());
+            bufSequence->pop();
+        }
+    }
+}
+