Added attempt to make pause / resume work with python module

3 files changed, 98 insertions, 10 deletions

diff --git a/python/examples/pause_resume.py b/python/examples/pause_resume.py
new file mode 100644
index 0000000..5daebeb
--- /dev/null
+++ b/python/examples/pause_resume.py
@@ -0,0 +1,35 @@
+# This example is meant to test the pause / resume / stop mechanism
+# See the solve.py example for more details on how this works
+
+import sys, os, time
+
+sys.path.append(os.getcwd())
+sys.path.append(os.getcwd() + os.path.sep + "python")
+import nissy
+
+# Function used to pause, resume and kill the solver
+t0 = time.time()
+def poll():
+        t = time.time() - t0
+        if t < 3:
+                print("[{}s] pausing for the first 3 seconds".format(t))
+                return nissy.status_pause
+        if t < 6:
+                print("[{}s] Letting the solver run for 3 seconds".format(t))
+                return nissy.status_run
+        print("[{}s] Too much time has passed, giving up".format(t))
+        return nissy.status_stop
+
+solver = "h48h0k4"
+datapath = "tables" + os.path.sep + solver
+if os.path.exists(datapath):
+        data = bytearray(open(datapath, "rb").read())
+else:
+        data = nissy.gendata("h48h0k4")
+        print("Generated data will NOT be persisted")
+
+# Scramble is 19 moves optimal, should take a while with the h48h0k4 solver
+scramble = "R' U' F D R F2 D L F D2 F2 L' U R' L2 D' R2 F2 R2 D L2 U2 R' U' F"
+cube = nissy.applymoves(nissy.solved_cube, scramble);
+
+nissy.solve(cube, solver, nissy.nissflag_normal, 0, 9, 3, 20, 4, data, poll)
diff --git a/python/examples/solve.py b/python/examples/solve.py
index 75e7914..c2c992b 100644
--- a/python/examples/solve.py
+++ b/python/examples/solve.py
@@ -3,12 +3,10 @@
 # Run "./build.sh python", then run this from either the top-level directory
 # of the nissy-core repo or from the python subdirectory.
 
-# Append the directories to the python path so we can load the module
+# Append the directories to the python path and import
 import sys, os
 sys.path.append(os.getcwd())
 sys.path.append(os.getcwd() + os.path.sep + "python")
-
-# Import with a nicer name
 import nissy
 
 # Choose the solver you prefer
@@ -26,7 +24,7 @@ else:
 cube = nissy.applymoves(nissy.solved_cube, "U F R2");
 
 # Solve!
-solutions = nissy.solve(cube, solver, nissy.nissflag_normal, 0, 9, 3, 20, 4, data)
+solutions = nissy.solve(cube, solver, nissy.nissflag_normal, 0, 9, 3, 20, 4, data, None)
 
 # Print the solutions, one per line
 print("Found ", len(solutions), " solutions:")
diff --git a/python/nissy_module.c b/python/nissy_module.c
index bff4ead..23ff589 100644
--- a/python/nissy_module.c
+++ b/python/nissy_module.c
@@ -1,3 +1,9 @@
+/*
+This version of the python module includes an attempt to use the callback
+functions for pausing / stopping / resuming a solve. It probably cannot
+work until PEP 703 (freethreading python) is implemented.
+*/
+
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 #include <stdbool.h>
@@ -6,6 +12,11 @@
 
 #define MAX_SOLUTIONS_SIZE 250000
 
+typedef struct {
+        PyObject *callback;
+        PyThreadState *thread_state;
+} thread_callback_t;
+
 static bool
 check_error(long long err)
 {
@@ -84,6 +95,32 @@ long_result(long long result)
         return PyLong_FromLong(result);
 }
 
+static int
+callback_wrapper(void *data)
+{
+        thread_callback_t *arg = data;
+        int r;
+        PyObject *result;
+        PyGILState_STATE gstate;
+
+        if (arg->callback != NULL && PyCallable_Check(arg->callback) == 1) {
+
+PyEval_RestoreThread(arg->thread_state);
+gstate = PyGILState_Ensure();
+                result = PyObject_CallNoArgs(data);
+PyGILState_Release(gstate);
+arg->thread_state = PyEval_SaveThread();
+
+                if (result == NULL)
+                        return 0;
+                Py_XDECREF(result);
+                r = PyLong_AsInt(result);
+                return r >= 0 && r <= 2 ? r : 0;
+        } else {
+                return NISSY_STATUS_RUN;
+        }
+}
+
 PyDoc_STRVAR(inverse_doc,
 "inverse(cube)\n"
 "--\n\n"
@@ -288,7 +325,7 @@ checkdata(PyObject *self, PyObject *args)
 
 PyDoc_STRVAR(solve_doc,
 "solve(cube, solver, nissflag, minmoves, maxmoves, maxsolutions,"
-" optimal, threads, data)\n"
+" optimal, threads, data, callback)\n"
 "--\n\n"
 "Solves the given 'cube' with the given 'solver' and other parameters."
 "See the documentation for libnissy (in nissy.h) for details.\n"
@@ -302,6 +339,9 @@ PyDoc_STRVAR(solve_doc,
 "  - optimal: the largest number of moves from the shortest solution\n"
 "  - threads: the number of threads to use (0 for default)\n"
 "  - data: a bytearray containing the data for the solver\n"
+"  - callback: a function that returns 0 (run), 1 (stop) or 2 (pause).\n"
+"              Polled by the solver to determine if the user requested the\n"
+"              to pause or stop the solve. Not used by all solvers.\n"
 "\n"
 "Returns: a list with the solutions found\n"
 );
@@ -315,17 +355,29 @@ solve(PyObject *self, PyObject *args)
         char solutions[MAX_SOLUTIONS_SIZE];
         long long stats[NISSY_SIZE_SOLVE_STATS];
         PyByteArrayObject *data;
+        PyObject *callback;
+        thread_callback_t callback_data;
 
-        if (!PyArg_ParseTuple(args, "ssIIIIIIY", &cube, &solver, &nissflag,
-             &minmoves, &maxmoves, &maxsolutions, &optimal, &threads, &data))
+        if (!PyArg_ParseTuple(args, "ssIIIIIIYO", &cube, &solver, &nissflag,
+             &minmoves, &maxmoves, &maxsolutions, &optimal, &threads, &data,
+             &callback))
                 return NULL;
 
-        Py_BEGIN_ALLOW_THREADS
+printf("Checking callback here:\n");
+PyObject *rrr = PyObject_CallNoArgs(callback);
+printf("result: %d\n", PyLong_AsInt(rrr));
+
+        callback_data.callback = callback;
+        callback_data.thread_state = PyEval_SaveThread();
+        //Py_BEGIN_ALLOW_THREADS
+
         result = nissy_solve(cube, solver, nissflag, minmoves, maxmoves,
             maxsolutions, optimal, threads, data->ob_alloc,
             (unsigned char *)data->ob_bytes, MAX_SOLUTIONS_SIZE, solutions,
-            stats, NULL, NULL);
-        Py_END_ALLOW_THREADS
+            stats, callback_wrapper, &callback_data);
+
+        PyEval_RestoreThread(callback_data.thread_state);
+        //Py_END_ALLOW_THREADS
 
         return stringlist_result(result, solutions);
 }
@@ -461,6 +513,9 @@ PyMODINIT_FUNC PyInit_nissy(void) {
         PyModule_AddIntConstant(module, "nissflag_mixed", NISSY_NISSFLAG_MIXED);
         PyModule_AddIntConstant(module, "nissflag_linear", NISSY_NISSFLAG_LINEAR);
         PyModule_AddIntConstant(module, "nissflag_all", NISSY_NISSFLAG_ALL);
+        PyModule_AddIntConstant(module, "status_run", NISSY_STATUS_RUN);
+        PyModule_AddIntConstant(module, "status_stop", NISSY_STATUS_STOP);
+        PyModule_AddIntConstant(module, "status_pause", NISSY_STATUS_PAUSE);
 
         return module;
 }