[PATCH 2/2] wininet: Implement InternetSetFilePointer

[Jason Kuo]

From: Jason Kuo

The function is implemented by setting cache file pointer to fill
read_buf. Consequently, when HTTPREQ_ReadFile is called, it will try
reading data from cache after read_buf is depleted, before continuing
reading from http stream.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=26570
---
 dlls/wininet/http.c     |  9 ++++++
 dlls/wininet/internet.c | 62 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/dlls/wininet/http.c b/dlls/wininet/http.c
index c9d1c463982..a672ae7fd8f 100644
--- a/dlls/wininet/http.c
+++ b/dlls/wininet/http.c
@@ -3184,6 +3184,15 @@ static DWORD HTTPREQ_ReadFile(object_header_t *hdr, void *buf, DWORD size, DWORD
             req->read_pos += read;
         }

+        if(read < size && SetFilePointer(req->hCacheFile, 0, NULL, FILE_CURRENT) < GetFileSize(req->hCacheFile, NULL)) {
+            while(read < size) {
+                res = ReadFile(req->hCacheFile, buf+read, size-read, &cread, NULL);
+                read += cread;
+                if(res != ERROR_SUCCESS || !cread)
+                    break;
+            }
+        }
+
         if(read < size && (!read || !(flags & IRF_NO_WAIT)) && !end_of_read_data(req)) {
             LeaveCriticalSection(&req->read_section);
             INTERNET_SendCallback(&req->hdr, req->hdr.dwContext, INTERNET_STATUS_RECEIVING_RESPONSE, NULL, 0);
diff --git a/dlls/wininet/internet.c b/dlls/wininet/internet.c
index 292fd44dd8e..136fb34e24c 100644
--- a/dlls/wininet/internet.c
+++ b/dlls/wininet/internet.c
@@ -2154,14 +2154,70 @@ INTERNET_STATUS_CALLBACK WINAPI InternetSetStatusCallbackW(

/***********************************************************************
  *           InternetSetFilePointer (WININET.@)
+ * Sets read position for an open internet file.
+ *
+ * RETURNS
+ *    Current position of the file on success
+ *    INVALID_SET_FILE_POINTER on failure
  */
 DWORD WINAPI InternetSetFilePointer(HINTERNET hFile, LONG lDistanceToMove,
     PVOID pReserved, DWORD dwMoveContext, DWORD_PTR dwContext)
 {
-    FIXME("(%p %ld %p %ld %Ix): stub\n", hFile, lDistanceToMove, pReserved, dwMoveContext, dwContext);
+    INT cache_pos;
+    DWORD read, cread;
+    DWORD err = ERROR_INTERNET_INVALID_OPERATION, res = INVALID_SET_FILE_POINTER;
+    http_request_t *request;
+
+    TRACE("(%p %ld %p %ld %Ix)\n", hFile, lDistanceToMove, pReserved, dwMoveContext, dwContext);
+
+    request = (http_request_t*)get_handle_object(hFile);
+
+    if(request->hdr.dwFlags & (INTERNET_FLAG_DONT_CACHE|INTERNET_FLAG_NO_CACHE_WRITE)) {
+        goto lend;
+    }
+
+    cache_pos = SetFilePointer(request->hCacheFile, 0, NULL, FILE_CURRENT);
+    switch (dwMoveContext) {
+        case FILE_BEGIN:
+            cache_pos = lDistanceToMove;
+            break;
+        case FILE_CURRENT:
+            if(cache_pos < 0 && lDistanceToMove < 0) {
+                err = ERROR_NEGATIVE_SEEK;
+                goto lend;
+            }
+            cache_pos += lDistanceToMove;
+            break;
+        case FILE_END:
+            FIXME("Unhandled dwMoveContext %ld\n", dwMoveContext);
+            goto lend;
+    }
+
+    if(GetFileSize(request->hCacheFile, NULL) < cache_pos) {
+        BYTE buf[1024];
+        while(GetFileSize(request->hCacheFile, NULL) < cache_pos) {
+            if(!InternetReadFile(hFile, buf, 1024, &cread))
+                break;
+        }
+    }
+
+    res = cache_pos;
+    cache_pos = SetFilePointer(request->hCacheFile, lDistanceToMove, NULL, dwMoveContext);
+    EnterCriticalSection(&request->read_section);
+    read = min(READ_BUFFER_SIZE, GetFileSize(request->hCacheFile, NULL)-cache_pos);
+    if(ReadFile(request->hCacheFile, request->read_buf, read, &cread, NULL)) {
+        request->read_size = cread;
+        request->read_pos = 0;
+    }
+    LeaveCriticalSection(&request->read_section);
+    err = NO_ERROR;

-    SetLastError(ERROR_INTERNET_INVALID_OPERATION);
-    return INVALID_SET_FILE_POINTER;
+lend:
+    SetLastError(err);
+    TRACE("returning %ld\n", res);
+    if(request)
+        WININET_Release( &request->hdr );
+    return res;
 }

/***********************************************************************