asyncinet.h File Reference

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Classes
struct	__AsyncInet

Typedefs
typedef struct __AsyncInet	ASYNCINET
typedef struct __AsyncInet *	pASYNCINET
typedef int(*	ASYNCINET_CALLBACK) (pASYNCINET AsyncInet, ASYNC_EVENT Event, WPARAM wParam, LPARAM lParam, VOID *Extension)

Enumerations
enum	ASYNC_EVENT { ASYNCINET_DATA , ASYNCINET_COMPLETE , ASYNCINET_CANCELLED , ASYNCINET_ERROR }

Functions
pASYNCINET	AsyncInetDownload (LPCWSTR lpszAgent, DWORD dwAccessType, LPCWSTR lpszProxy, LPCWSTR lpszProxyBypass, LPCWSTR lpszUrl, BOOL bAllowCache, ASYNCINET_CALLBACK Callback, VOID *Extension)
BOOL	AsyncInetCancel (pASYNCINET AsyncInet)
VOID	AsyncInetRelease (pASYNCINET AsyncInet)

Typedef Documentation

ASYNCINET

typedef struct __AsyncInet ASYNCINET

Definition at line 19 of file asyncinet.h.

ASYNCINET_CALLBACK

typedef int(* ASYNCINET_CALLBACK) (pASYNCINET AsyncInet, ASYNC_EVENT Event, WPARAM wParam, LPARAM lParam, VOID *Extension)

Definition at line 21 of file asyncinet.h.

pASYNCINET

typedef struct __AsyncInet * pASYNCINET

Definition at line 19 of file asyncinet.h.

Enumeration Type Documentation

ASYNC_EVENT

enum ASYNC_EVENT

Enumerator
ASYNCINET_DATA
ASYNCINET_COMPLETE
ASYNCINET_CANCELLED
ASYNCINET_ERROR

Definition at line 5 of file asyncinet.h.

{
    ASYNCINET_DATA,           // wParam is the Data retrieved from the internet, lParam is the length of Data
 
    ASYNCINET_COMPLETE,       // wParam and lParam are not used.
                              // when receiving this, AsyncInet will be free soon and should not used anymore
 
    ASYNCINET_CANCELLED,      // wParam and lParam are not used.
                              // when receiving this, AsyncInet will be free soon and should not used anymore
 
    ASYNCINET_ERROR           // wParam is not used. lParam specify the error code (if there is one).
                              // when receiving this, AsyncInet will be free soon and should not used anymore
};

Function Documentation

AsyncInetCancel()

BOOL AsyncInetCancel

(

pASYNCINET

AsyncInet

)

Definition at line 126 of file asyncinet.cpp.

{
    if (AsyncInet)
    {
        HINTERNET hInetFile;
        EnterCriticalSection(&(AsyncInet->CriticalSection));
        AsyncInet->bCancelled = TRUE;
        hInetFile = AsyncInet->hInetFile;
        AsyncInet->hInetFile = NULL;
        LeaveCriticalSection(&(AsyncInet->CriticalSection));
 
        if (hInetFile)
        {
            InternetCloseHandle(hInetFile);
            return TRUE;
        }
    }
 
    return FALSE;
}

Referenced by CAppScrnshotPreview::PreviousDisplayCleanup().

AsyncInetDownload()

pASYNCINET AsyncInetDownload	(	LPCWSTR	lpszAgent,
		DWORD	dwAccessType,
		LPCWSTR	lpszProxy,
		LPCWSTR	lpszProxyBypass,
		LPCWSTR	lpszUrl,
		BOOL	bAllowCache,
		ASYNCINET_CALLBACK	Callback,
		VOID *	Extension
	)

Definition at line 33 of file asyncinet.cpp.

{
    pASYNCINET AsyncInet = NULL;
    BOOL bSuccess = FALSE;
    DWORD InetOpenUrlFlag = 0;
    INTERNET_STATUS_CALLBACK OldCallbackFunc;
 
    AsyncInet = (pASYNCINET)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(ASYNCINET));
    if (!AsyncInet)
    {
        OutputDebugStringA("At File: " __FILE__ " HeapAlloc returned 0\n");
        return 0;
    }
 
    AsyncInet->bCancelled = FALSE;
 
    AsyncInet->hInternet = NULL;
    AsyncInet->hInetFile = NULL;
 
    AsyncInet->Callback = Callback;
    AsyncInet->Extension = Extension;
 
    AsyncInet->hEventHandleCreated = CreateEvent(NULL, FALSE, FALSE, NULL);
 
    InitializeCriticalSection(&(AsyncInet->CriticalSection));
    AsyncInet->ReferenceCnt = 1; // 1 for callee itself
    AsyncInet->hEventHandleClose = CreateEvent(NULL, FALSE, FALSE, NULL);
 
    if (AsyncInet->hEventHandleCreated && AsyncInet->hEventHandleClose)
    {
        AsyncInet->hInternet = InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, INTERNET_FLAG_ASYNC);
 
        if (AsyncInet->hInternet)
        {
            OldCallbackFunc = InternetSetStatusCallbackW(AsyncInet->hInternet, AsyncInetStatusCallback);
            if (OldCallbackFunc != INTERNET_INVALID_STATUS_CALLBACK)
            {
                InetOpenUrlFlag |= INTERNET_FLAG_PASSIVE | INTERNET_FLAG_RESYNCHRONIZE;
                if (!bAllowCache)
                {
                    InetOpenUrlFlag |= INTERNET_FLAG_DONT_CACHE | INTERNET_FLAG_PRAGMA_NOCACHE | INTERNET_FLAG_RELOAD;
                }
 
                AsyncInet->hInetFile = InternetOpenUrlW(AsyncInet->hInternet, lpszUrl, 0, 0, InetOpenUrlFlag, (DWORD_PTR)AsyncInet);
 
                if (AsyncInet->hInetFile)
                {
                    // operate complete synchronously
                    bSuccess = TRUE;
                    AsyncInetReadFileLoop(AsyncInet);
                }
                else
                {
                    if (GetLastError() == ERROR_IO_PENDING)
                    {
                        // everything fine. waiting for handle created
                        switch (WaitForSingleObject(AsyncInet->hEventHandleCreated, INFINITE))
                        {
                        case WAIT_OBJECT_0:
                            if (AsyncInet->hInetFile)
                            {
                                bSuccess = TRUE;
                            }
                        }
                    }
                }
            }
        }
    }
 
    if (!bSuccess)
    {
        AsyncInetFree(AsyncInet);
        AsyncInet = NULL;
    }
 
    if (AsyncInet)
    {
        // add reference count for caller.
        // the caller is responsible for call AsyncInetRelease when no longer using it.
        AsyncInetAcquire(AsyncInet);
    }
    return AsyncInet;
}

Referenced by CAppScrnshotPreview::DisplayImage().

AsyncInetRelease()

VOID AsyncInetRelease

(

pASYNCINET

AsyncInet

)

Definition at line 184 of file asyncinet.cpp.

{
    BOOL bCleanUp = FALSE;
    if (AsyncInet)
    {
        EnterCriticalSection(&(AsyncInet->CriticalSection));
 
        ATLASSERT(AsyncInet->ReferenceCnt);
        AsyncInet->ReferenceCnt--;
        if (AsyncInet->ReferenceCnt == 0)
        {
            bCleanUp = TRUE;
        }
 
        LeaveCriticalSection(&(AsyncInet->CriticalSection));
 
        if (bCleanUp)
        {
            AsyncInetCleanUp(AsyncInet);
        }
    }
}

Referenced by AsyncInetReadFileLoop(), AsyncInetStatusCallback(), and CAppScrnshotPreview::ProcessWindowMessage().