backout f600f0cd7bb3 (Bug 1170646) because of Thunderbird regressions with OSX, r=michal, a=sylvestre

--HG--
extra : transplant_source : k%82%8EI%D0%1C%E1%60%8F%E9%3CA%22%AA%91j-%24%A6%15

netwerk/cache/nsDiskCacheBlockFile.cpp

@@ -13,33 +13,6 @@
 
 using namespace mozilla;
 
-/* to cope with short read.
- * xxx not sure  if we want to repeat PR_Read() if no octet is ever read
- * and is errno == EINTR
- */
-static
-PRInt32
-busy_beaver_PR_Read(PRFileDesc *fd, void * start, PRInt32 len)
-{
-    int n;
-    PRInt32 remaining = len;
-
-    while (remaining > 0) {
-        n = PR_Read(fd, start, remaining);
-        if (n < 0) {
-            if( (len - remaining) == 0 ) // no octet is ever read
-                return -1;
-            break;
-        } else {
-            remaining -= n;
-            char *cp = (char *) start;
-            cp += n;
-            start = cp;
-        }
-    }
-    return len - remaining;
-}
-
 /******************************************************************************
  * nsDiskCacheBlockFile - 
  *****************************************************************************/
@@ -101,7 +74,7 @@ nsDiskCacheBlockFile::Open(nsIFile * blockFile,
         
     } else {
         // read the bit map
-        const int32_t bytesRead = busy_beaver_PR_Read(mFD, mBitMap, bitMapBytes);
+        const int32_t bytesRead = PR_Read(mFD, mBitMap, bitMapBytes);
         if ((bytesRead < 0) || ((uint32_t)bytesRead < bitMapBytes)) {
             *corruptInfo = nsDiskCache::kBlockFileBitMapReadError;
             rv = NS_ERROR_UNEXPECTED;
@@ -280,15 +253,11 @@ nsDiskCacheBlockFile::ReadBlocks( void *    buffer,
     if ((bytesToRead <= 0) || ((uint32_t)bytesToRead > mBlockSize * numBlocks)) {
         bytesToRead = mBlockSize * numBlocks;
     }
-    /* This has to tolerate short read, i.e., we need to repeat! */
-    *bytesRead = busy_beaver_PR_Read(mFD, buffer, bytesToRead);
-
+    *bytesRead = PR_Read(mFD, buffer, bytesToRead);
+    
     CACHE_LOG_DEBUG(("CACHE: nsDiskCacheBlockFile::Read [this=%p] "
                      "returned %d / %d bytes", this, *bytesRead, bytesToRead));
 
-    if(*bytesRead == -1)
-        return NS_ERROR_UNEXPECTED;
-
     return NS_OK;
 }