Changeset 911 for trunk/src

Timestamp:

Jul 25, 2011, 2:36:02 PM (14 years ago)

Author:

Dmitry A. Kuminov

Message:

OS/2: QProcess: Don't close the stdin pipe until the child reads it all.

This fixes the cases when the child process receives truncated data sent to its stdin by the parent process with QProcess::write(). This is due to the fact that writing a chunk of data to a pipe and then closing it will make this data unavailable to the other end if it is not fast enough to read it in between.

Location:

trunk/src/corelib/io

Files:

• qprocess.cpp (modified) (2 diffs)
• qprocess_os2.cpp (modified) (4 diffs)
• qprocess_p.h (modified) (3 diffs)

trunk/src/corelib/io/qprocess.cpp

@@ -971 +971 @@
         qDebug("QProcessPrivate::canWrite(), not writing anything (empty write buffer).");
 #endif
+#if defined Q_OS_OS2
+        if (stdinChannel.pipe.closePending)
+            tryCloseStdinPipe();
+#endif
         return false;
     }
@@ -1122 +1126 @@
     flushPipeWriter();
 #endif
+#ifdef Q_OS_OS2
+    // postpone the real close until the other end reads all from the pipe buf
+    stdinChannel.pipe.closePending = true;
+    tryCloseStdinPipe();
+#else
     destroyPipe(stdinChannel.pipe);
+#endif
 }
 

trunk/src/corelib/io/qprocess_os2.cpp

@@ -553 +553 @@
     pipe.server = HPIPE(~0);
     pipe.client = HFILE(~0);
+    pipe.closePending = false;
 
     // we need the process identifier to guarantee pipe name unicity
@@ -612 +613 @@
 void QProcessPrivate::destroyPipe(Channel::Pipe &pipe)
 {
+    pipe.closePending = false;
+
     if (pipe.client != ~HFILE(~0)) {
         DosClose(pipe.client);
@@ -634 +637 @@
     channel.pipe.server = HPIPE(~0);
     channel.pipe.client = HFILE(~0);
+    channel.pipe.closePending = false;
 
     if (&channel == &stderrChannel && processChannelMode == QProcess::MergedChannels) {
@@ -1342 +1346 @@
 }
 
+void QProcessPrivate::tryCloseStdinPipe()
+{
+    Q_ASSERT(stdinChannel.pipe.closePending);
+
+    if (stdinChannel.pipe.closePending) {
+        // grab new bytes from QProcessManager (if any)
+        int newBytes = pipeData[InPipe].newBytes.fetchAndStoreRelaxed(0);
+        if (newBytes)
+            pipeData[InPipe].bytesLeft = newBytes;
+        if (pipeData[InPipe].bytesLeft == PIPE_SIZE_STDIN) {
+            // the other end has read everything from the pipe buf so that it's
+            // safe to close it now (satisfy the closeWriteChannel() request)
+            destroyPipe(stdinChannel.pipe);
+        }
+    }
+}
+
 qint64 QProcessPrivate::writeToStdin(const char *data, qint64 maxlen)
 {

trunk/src/corelib/io/qprocess_p.h

@@ -118 +118 @@
             pipe.server = HPIPE(~0);
             pipe.client = HFILE(~0);
+            pipe.closePending = false;
 #else
             pipe[0] = INVALID_Q_PIPE;
@@ -155 +156 @@
             HPIPE server;
             HFILE client;
+            bool closePending;
         };
         Pipe pipe;
@@ -243 +245 @@
     void uninit();
     void ensureWaitSem();
+    void tryCloseStdinPipe();
 #endif