sat: factor the creation of temporary files

* src/misc/satsolver.hh, src/misc/satsolver.cc: Present
the SAT solver as an object with a stream interface, to
prepare for a better implementation.
* src/tgbaalgos/dtbasat.cc, src/tgbaalgos/dtgbasat.cc:
Adjust to the new interface, removing all the handling
of temporary files.
* src/tgbatest/readsat.cc: Adjust.

src/misc/satsolver.cc

@@ -83,18 +83,10 @@ namespace spot
     };
   }
 
-  int satsolver(printable* input, printable* output)
-  {
-    // Make this static, so the SPOT_SATSOLVER lookup is done only on
-    // the first call to run_sat().
-    static satsolver_command cmd;
-    return cmd.run(input, output);
-  }
-
-  sat_solution
+  satsolver::solution
   satsolver_get_solution(const char* filename)
   {
-    sat_solution sol;
+    satsolver::solution sol;
     std::istream* in;
     if (filename[0] == '-' && filename[1] == 0)
       in = &std::cin;
@@ -130,4 +122,47 @@ namespace spot
     return sol;
   }
 
+  satsolver::satsolver()
+    : cnf_tmp_(0), cnf_stream_(0)
+  {
+    start();
+  }
+
+  void satsolver::start()
+  {
+    cnf_tmp_ = create_tmpfile("sat-", ".cnf");
+    cnf_stream_ = new std::fstream(cnf_tmp_->name(),
+				   std::ios_base::trunc | std::ios_base::out);
+    cnf_stream_->exceptions(std::ifstream::failbit | std::ifstream::badbit);
+  }
+
+  satsolver::~satsolver()
+  {
+    delete cnf_tmp_;
+    delete cnf_stream_;
+  }
+
+  std::ostream& satsolver::operator()()
+  {
+    return *cnf_stream_;
+  }
+
+  satsolver::solution_pair
+  satsolver::get_solution()
+  {
+    delete cnf_stream_;		// Close the file.
+    cnf_stream_ = 0;
+
+    temporary_file* output = create_tmpfile("sat-", ".out");
+    solution_pair p;
+
+    // Make this static, so the SPOT_SATSOLVER lookup is done only on
+    // the first call to run_sat().
+    static satsolver_command cmd;
+
+    p.first = cmd.run(cnf_tmp_, output);
+    p.second = satsolver_get_solution(output->name());
+    delete output;
+    return p;
+  }
 }

src/misc/satsolver.hh

@@ -21,8 +21,10 @@
 #define SPOT_MISC_SATSOLVER_HH
 
 #include "common.hh"
+#include "tmpfile.hh"
 #include <vector>
 #include <stdexcept>
+#include <iosfwd>
 
 namespace spot
 {
@@ -65,29 +67,37 @@ namespace spot
     }
   };
 
-  /// \brief Run a SAT solver.
+  /// \brief Interface with a SAT solver.
   ///
-  /// Run a SAT solver using the input in file \a input,
-  /// and sending output in file \a output.
+  /// Call start() to create some temporary file, then send DIMACs
+  /// text to the stream returned by operator(), and finally call
+  /// get_solution().
   ///
-  /// These two arguments are instance of printable, as
-  /// they will be evaluated in a %-escaped string such as
-  ///    "satsolver %I >%O"
-  /// This command can be overridden using the
-  /// <code>SPOT_SATSOLVER</code> environment variable.
-  ///
-  /// Note that temporary_file instances implement the
-  /// printable interface.
-  SPOT_API int
-  satsolver(printable* input, printable* output);
+  /// The satsolver called can be configured via the
+  /// <code>SPOT_SATSOLVER</code> environment variable.  It
+  /// defaults to
+  ///    "satsolver -verb=0 %I >%O"
+  /// where %I and %O are replaced by input and output files.
+  class SPOT_API satsolver
+  {
+  public:
+    satsolver();
+    ~satsolver();
 
+    void start();
+    std::ostream& operator()();
 
-  typedef std::vector<int> sat_solution;
+    typedef std::vector<int> solution;
+    typedef std::pair<int, solution> solution_pair;
+    solution_pair get_solution();
+  private:
+    temporary_file* cnf_tmp_;
+    std::ostream* cnf_stream_;
+  };
 
   /// \brief Extract the solution of a SAT solver output.
-  SPOT_API sat_solution
+  SPOT_API satsolver::solution
   satsolver_get_solution(const char* filename);
-
 }
 
 #endif // SPOT_MISC_SATSOLVER_HH