it works perfectly with blocking pipes and buffer size of 1

mrw/exec.cpp

@@ -9,6 +9,9 @@
     @license LGPL, see file <a href="license.html">COPYING</a>
 
     $Log$
+    Revision 1.7  2004/12/17 17:38:57  marc
+    it works perfectly with blocking pipes and buffer size of 1
+
     Revision 1.6  2004/12/17 16:28:51  marc
     stable implementation with select for both executes
 
@@ -38,6 +41,7 @@
 #include <string.h>  // memcpy
 #include <assert.h> // assert
 
+#include <iostream>
 mrw::ExecutionFailedExc::ExecutionFailedExc(const std::string& w,
                                             const std::string& c)
   throw(std::bad_exception):
@@ -129,7 +133,7 @@ mrw::Exec& mrw::Exec::execute(bool exc) throw(std::exception) {
       program. */
   _success = false;
   _res = _err = "";
-  mrw::Pipe stdOut, stdErr;
+  mrw::Pipe stdOut(true), stdErr(true);
   if (!stdOut || !stdErr)
     throw mrw::ExecutionFailedExc("cannot create pipe", *_cmd);
   pid_t pid(fork());
@@ -142,8 +146,12 @@ mrw::Exec& mrw::Exec::execute(bool exc) throw(std::exception) {
       throw ExecutionFailedExc("cannot close pipe", *_cmd);
     ssize_t num1(-1), num2(-1);
     fd_set readfds;
-    char buf[4096];
+    char buf[1]; // used to have larger buffer, but since non blocking fails...
     int res(0), s(0);
+    /** @bug It sometimes did not get the whole input since I
+             changed to non blocking pipes. Now pipes are blocking
+             again and buffer size is 1, so I hope all problems are
+             resolved. Please report any problems! */
     while (num1||num2) try { // not all end of file
       if (!res && (res=waitpid(pid, &s, WNOHANG)))
         if (res!=pid || WIFEXITED(s)!=0 && WEXITSTATUS(s)!=0)
@@ -155,7 +163,7 @@ mrw::Exec& mrw::Exec::execute(bool exc) throw(std::exception) {
       int n(mrw::max((num1?stdOut.istream():0),
                      (num2?stdErr.istream():0)));
       timeval tm = {0, 10000};
-      int num = select(n, &readfds, 0, 0, &tm);
+      int num = select(n+1, &readfds, 0, 0, 0);
       if (num<0) throw ExecutionFailedExc("select failed", *_cmd);
       if (num==0 && res==pid) break; // process ended, no data left
       // check and handle stdout
@@ -175,6 +183,7 @@ mrw::Exec& mrw::Exec::execute(bool exc) throw(std::exception) {
       _success = false;
       return *this;
     }
+    std::cout<<"num1="<<num1<<", num2="<<num2<<std::endl;
   } else { // child
     stdOut.close_in();
     stdErr.close_in();
@@ -201,7 +210,7 @@ mrw::Exec& mrw::Exec::execute(const std::string& input, bool exc)
   _success = false;
   _res = _err = "";
   mrw::Pipe stdIn(true), // child terminates if stdin is non-blocking
-     stdOut, stdErr;
+    stdOut(true), stdErr(true); // non blocking is also a problem here
   if (!stdIn || !stdOut || !stdErr)
     throw mrw::ExecutionFailedExc("cannot create pipe", *_cmd);
   pid_t pid(fork());
@@ -215,8 +224,12 @@ mrw::Exec& mrw::Exec::execute(const std::string& input, bool exc)
     ssize_t num0(-1), num1(-1), num2(-1);
     std::string in(input);
     fd_set writefds, readfds;
-    char buf[4096];
+    char buf[1]; // used to have larger buffer, but since non blocking fails...
     int res(0), s(0);
+    /** @bug It sometimes did not get the whole input since I
+             changed to non blocking pipes. Now pipes are blocking
+             again and buffer size is 1, so I hope all problems are
+             resolved. Please report any problems! */
     while (num0||num1||num2) try { // not all end of file
       if (!res && (res=waitpid(pid, &s, WNOHANG)))
         if (res!=pid || WIFEXITED(s)!=0 && WEXITSTATUS(s)!=0)
@@ -231,7 +244,7 @@ mrw::Exec& mrw::Exec::execute(const std::string& input, bool exc)
                      mrw::max((num1?stdOut.istream():0),
                               (num2?stdErr.istream():0))));
       timeval tm = {0, 10000};
-      int num = select(n, &readfds, &writefds, 0, &tm);
+      int num = select(n+1, &readfds, &writefds, 0, &tm);
       if (num<0) throw ExecutionFailedExc("select failed", *_cmd);
       if (num==0 && res==pid) break; // process ended, no data left
       // check and handle stdin
@@ -261,6 +274,7 @@ mrw::Exec& mrw::Exec::execute(const std::string& input, bool exc)
       _success = false;
       return *this;
     }
+    std::cout<<"num0="<<num0<<", num1="<<num1<<", num2="<<num2<<std::endl;
   } else { // child
     stdIn.close_out();
     stdOut.close_in();