osl: Unix pipe converted from OSL_ASSERT to assert/SAL_WARNs

Explanation for each conversion:

- osl_acceptPipe()
    - don't worry about an invalid oslPipe sent as function parameter an
      error gets flagged in Unix normally, so it might not be a
      programming error
    - definitely assert on an empty name, that's a definite programming
      error and should never, ever occur
    - createPipeImpl() allocates and initializes memory for the
      oslPipeImpl structure, if it can't do this then something has been
      done wrongly

- osl_receivePipe()
    - invalid oslPipe sent as function parameter might not be a
      programming error, give a warning but don't assert

- osl_sendPipe()
    - invalid oslPipe sent as function parameter might not be a
      programming error, give a warning but don't assert

- osl_writePipe()
    - really just a thin wrapper around osl_sendPipe(), which detects
      and handles invalid pipes

- osl_readPipe()
    - really just a thin wrapper around osl_receivePipe(), which detects
      and handles invalid pipes

Change-Id: I4923265b4c648852743c406b682d43ffb9ac6537
Reviewed-on: https://gerrit.libreoffice.org/40003
Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>
Tested-by: Chris Sherlock <chris.sherlock79@gmail.com>

sal/osl/unx/pipe.cxx

@@ -31,6 +31,8 @@
 #include "sockimpl.hxx"
 #include "secimpl.hxx"
 
+#include <cassert>
+
 #define PIPEDEFAULTPATH     "/tmp"
 #define PIPEALTERNATEPATH   "/var/tmp"
 
@@ -397,11 +399,11 @@ oslPipe SAL_CALL osl_acceptPipe(oslPipe pPipe)
     int s;
     oslPipe pAcceptedPipe;
 
-    OSL_ASSERT(pPipe);
+    SAL_WARN_IF(!pPipe, "sal.osl.pipe", "invalid pipe");
     if (!pPipe)
         return nullptr;
 
-    OSL_ASSERT(strlen(pPipe->m_Name) > 0);
+    assert(strlen(pPipe->m_Name) > 0);  // you cannot have an empty pipe name
 
 #if defined(CLOSESOCKET_DOESNT_WAKE_UP_ACCEPT)
     pPipe->m_bIsAccepting = true;
@@ -430,7 +432,7 @@ oslPipe SAL_CALL osl_acceptPipe(oslPipe pPipe)
     /* alloc memory */
     pAcceptedPipe = createPipeImpl();
 
-    OSL_ASSERT(pAcceptedPipe);
+    assert(pAcceptedPipe);  // should never be the case that an oslPipe cannot be initialized
     if (!pAcceptedPipe)
     {
         close(s);
@@ -457,8 +459,7 @@ sal_Int32 SAL_CALL osl_receivePipe(oslPipe pPipe,
 {
     int nRet = 0;
 
-    OSL_ASSERT(pPipe);
+    SAL_WARN_IF(!pPipe, "sal.osl.pipe", "osl_receivePipe: invalid pipe");
-
     if (!pPipe)
     {
         SAL_WARN("sal.osl.pipe", "osl_receivePipe: Invalid socket");
@@ -480,8 +481,7 @@ sal_Int32 SAL_CALL osl_sendPipe(oslPipe pPipe,
 {
     int nRet=0;
 
-    OSL_ASSERT(pPipe);
+    SAL_WARN_IF(!pPipe, "sal.osl.pipe", "osl_sendPipe: invalid pipe");
-
     if (!pPipe)
     {
         SAL_WARN("sal.osl.pipe", "osl_sendPipe: Invalid socket");
@@ -508,7 +508,7 @@ sal_Int32 SAL_CALL osl_writePipe(oslPipe pPipe, const void *pBuffer, sal_Int32 n
     sal_Int32 BytesSend = 0;
     sal_Int32 BytesToSend = n;
 
-    OSL_ASSERT(pPipe);
+    SAL_WARN_IF(!pPipe, "sal.osl.pipe", "osl_writePipe: invalid pipe"); // osl_sendPipe detects invalid pipe
     while (BytesToSend > 0)
     {
         sal_Int32 RetVal;
@@ -533,7 +533,7 @@ sal_Int32 SAL_CALL osl_readPipe( oslPipe pPipe, void *pBuffer , sal_Int32 n )
     sal_Int32 BytesRead = 0;
     sal_Int32 BytesToRead = n;
 
-    OSL_ASSERT(pPipe);
+    SAL_WARN_IF(!pPipe, "sal.osl.pipe", "osl_readPipe: invalid pipe"); // osl_receivePipe detects invalid pipe
     while (BytesToRead > 0)
     {
         sal_Int32 RetVal;