Add GAP kernel API (aka libgap)

.gitignore

@@ -86,3 +86,6 @@ doc/gapmacrodoc.idx
 /hpcgap/ward
 
 /builds/
+
+/libgap.la
+/.libs

.travis.yml

@@ -108,6 +108,9 @@ matrix:
     # test error reporting and compiling (quickest job in this test suite)
     - env: TEST_SUITES="testspecial test-compile"
 
+    # test libgap
+    - env: TEST_SUITES="testlibgap" CONFIGFLAGS="--enable-debug --enable-Werror --enable-libgap"
+
 script:
   - gcov --version
   - bash etc/ci-prepare.sh && bash etc/ci.sh

GNUmakefile.in

@@ -24,6 +24,9 @@ ADDGUARDS2 = @ADDGUARDS2@
 # garbage collector source files
 GC_SOURCES = @GC_SOURCES@
 
+# Dynamic library
+BUILD_LIBGAP = @BUILD_LIBGAP@
+
 # compatibility mode
 COMPAT_MODE = @COMPAT_MODE@
 GAPARCH = @GAPARCH@

Makefile.rules

@@ -16,7 +16,7 @@
 all: gap$(EXEEXT) gac
 .PHONY: all
 
-libgap: libgap.la
+libgap: libgap.la sysinfo.gap symlinks
 .PHONY: libgap
 
 # Backwards compatibility: add "default" target as alias for "all"
@@ -64,6 +64,7 @@ SOURCES += src/intfuncs.c
 SOURCES += src/intrprtr.c
 SOURCES += src/io.c
 SOURCES += src/iostream.c
+SOURCES += src/libgap-api.c
 SOURCES += src/listfunc.c
 SOURCES += src/listoper.c
 SOURCES += src/lists.c
@@ -121,7 +122,6 @@ ifeq ($(HPCGAP),yes)
   SOURCES += src/hpc/traverse.c
 endif
 
-
 ########################################################################
 # Preprocessor flags
 #
@@ -395,6 +395,8 @@ gap$(EXEEXT): $(OBJS) cnf/GAP-LDFLAGS cnf/GAP-LIBS cnf/GAP-OBJS
 
 endif
 
+libgap.so: $(OBJS)
+	$(QUIET_LINK)$(LINK) $(GAP_LDFLAGS) -shared $(OBJS) $(GAP_LIBS) -o $@
 
 ########################################################################
 # The "docomp" target regenerates the various src/c_*.c files, and
@@ -986,6 +988,12 @@ testbugfix: all
           ReadGapRoot( "tst/testbugfix.g" );' | $(TESTGAP) | \
             tee `date -u +dev/log/testbugfix2_%Y-%m-%d-%H-%M` )
 
+testlibgap: libgap.la obj/tst/testlibgap/basic.lo 
+	$(QUIET_LINK)$(LINK) $(GAP_LDFLAGS) obj/tst/testlibgap/basic.lo libgap.la -o test-libgap
+	./test-libgap -l $(top_srcdir) -m 32m -q -T > basic.out
+	diff $(top_srcdir)/tst/testlibgap/basic.expect basic.out
+.PHONY: testlibgap
+
 coverage:
 	gcov -o . $(SOURCES)
 

etc/ci.sh

@@ -177,6 +177,10 @@ GAPInput
 
     ;;
 
+  testlibgap)
+    make testlibgap
+    ;;
+
   *)
     if [[ ! -f  $SRCDIR/tst/${TEST_SUITE}.g ]]
     then

lib/init.g

@@ -1042,11 +1042,12 @@ if IsLIBGAP then
 elif IsHPCGAP and THREAD_UI() then
   ReadLib("hpc/consoleui.g");
   MULTI_SESSION();
-else
+  PROGRAM_CLEAN_UP();
+elif not IsLIBGAP then
   SESSION();
+  PROGRAM_CLEAN_UP();
 fi;
 
-PROGRAM_CLEAN_UP();
 
 
 #############################################################################

lib/streams.gi

@@ -234,14 +234,6 @@ function( stream )
     CloseStream(stream);
 end );
 
-BindGlobal("LIBGAP_EvalString",
-function(string)
-   local instream, obj;
-   instream := InputTextString(string);
-   obj := READ_ALL_COMMANDS(instream, 0, false);
-   return obj;
-end);
-
 
 #############################################################################
 ##

src/libgap-api.c

@@ -0,0 +1,95 @@
+// LibGAP API - API for using GAP as shared library.
+
+#include "libgap-api.h"
+
+#include "bool.h"
+#include "opers.h"
+#include "calls.h"
+#include "gapstate.h"
+#include "gvars.h"
+#include "lists.h"
+#include "streams.h"
+#include "stringobj.h"
+
+//
+// Setup and initialisation
+//
+void GAP_Initialize(int          argc,
+                    char **      argv,
+                    char **      env,
+                    CallbackFunc markBagsCallback,
+                    CallbackFunc errorCallback)
+{
+    InitializeGap(&argc, argv, env);
+    SetExtraMarkFuncBags(markBagsCallback);
+    STATE(JumpToCatchCallback) = errorCallback;
+}
+
+
+UInt GAP_List_Length(Obj list)
+{
+    return LEN_LIST(list);
+}
+
+Obj GAP_List_AtPosition(Obj list, Int pos)
+{
+    return ELM_LIST(list, pos);
+}
+
+UInt GAP_String_Length(Obj string)
+{
+    return GET_LEN_STRING(string);
+}
+
+Int GAP_String_GetCString(Obj string, Char * buffer, UInt n)
+{
+    Obj copy;
+    UInt len;
+
+    if (IS_STRING(string)) {
+        copy = CopyToStringRep(string);
+        len = GET_LEN_STRING(copy) + 1;
+        if (len >= n)
+            len = n-1;
+        // Have to use mempcy because GAP strings can contain
+        // \0.
+        memcpy(buffer, CSTR_STRING(copy), len);
+        if (len == n-1)
+            buffer[n] = '\0';
+        return 1;
+    }
+    return 0;
+}
+
+
+// Combines GVarName and ValGVar. For a given string, it returns the value
+// of the gvar with name <name>, or NULL if the global variable is not
+// defined.
+Obj GAP_ValueGlobalVariable(const char * name)
+{
+    UInt gvar = GVarName(name);
+    // TODO: GVarName should never return 0?
+    if (gvar != 0) {
+        return ValGVar(gvar);
+    }
+    else {
+        return NULL;
+    }
+}
+
+//
+// Evaluate a string of GAP commands
+//
+Obj GAP_EvalString(const char * cmd)
+{
+    Obj instream;
+    Obj res;
+    Obj viewObjFunc, streamFunc;
+
+    streamFunc = GAP_ValueGlobalVariable("InputTextString");
+    viewObjFunc = GAP_ValueGlobalVariable("ViewObj");
+
+    instream = DoOperation1Args(streamFunc, MakeString(cmd));
+    res = READ_ALL_COMMANDS(instream, False, True, viewObjFunc);
+    return res;
+}

src/libgap-api.h

@@ -0,0 +1,47 @@
+// LibGAP API - API for using GAP as shared library.
+//
+// WARNING
+//
+// This API is work in progress, hence subject to change.
+//
+// We currently only provide a small amount of functionality
+// via a well-defined API that wraps internal GAP functions.
+//
+// Users of GAP as a library currently call directly into
+// GAP kernel functions. In the future we would like to hide
+// all GAP internal functions (in the .so/.dll file) and only
+// allow access to GAP via functions defined in this file.
+//
+// If you have a request to expose functionality via the API
+// please contact us via the GAP mailing list or github
+// issue tracker.
+//
+
+#ifndef LIBGAP_API_H
+#define LIBGAP_API_H
+
+#include "gap.h"
+
+typedef void (*CallbackFunc)(void);
+
+// Initialisation and finalization
+
+void GAP_Initialize(int          argc,
+                    char **      argv,
+                    char **      env,
+                    CallbackFunc markBagsCallback,
+                    CallbackFunc errorCallback);
+
+// List operations. These are currently here like this, because they are used in
+// testlibgap.
+UInt GAP_List_Length(Obj list);
+Obj GAP_List_AtPosition(Obj list, Int pos);
+
+UInt GAP_String_Length(Obj string);
+Int GAP_String_GetCString(Obj string, Char *buffer, UInt max);
+
+Obj GAP_ValueGlobalVariable(const char * name);
+
+Obj GAP_EvalString(const char * cmd);
+
+#endif

tst/testlibgap/basic.c

@@ -0,0 +1,49 @@
+/*
+ * Small program to test libgap linkability and basic working
+ */
+#include <stdio.h>
+#include <unistd.h>
+
+#include <compiled.h>
+#include <libgap-api.h>
+
+extern char ** environ;
+
+void test_eval(const char * cmd)
+{
+    Obj  res, ires;
+    Int  rc, i;
+    Char buffer[4096];
+
+    printf("gap> %s\n", cmd);
+    res = GAP_EvalString(cmd);
+    rc = GAP_List_Length(res);
+    for (i = 1; i <= rc; i++) {
+        ires = GAP_List_AtPosition(res, i);
+        if (GAP_List_AtPosition(ires, 1) == True) {
+            GAP_String_GetCString(GAP_List_AtPosition(ires, 5), buffer,
+                           sizeof(buffer));
+            printf("%s\n", buffer);
+        }
+    }
+}
+
+int main(int argc, char ** argv)
+{
+    printf("# Initializing GAP...\n");
+    GAP_Initialize(argc, argv, environ, 0L, 0L);
+
+    CollectBags(0, 1);    // full GC
+
+    test_eval("1+2+3;");
+    test_eval("g:=FreeGroup(2);");
+    test_eval("a:=g.1;");
+    test_eval("b:=g.2;");
+    test_eval("lis:=[a^2, a^2, b*a];");
+    test_eval("h:=g/lis;");
+    test_eval("c:=h.1;");
+    test_eval("Set([1..1000000], i->Order(c));");
+
+    printf("# done\n");
+    return 0;
+}

tst/testlibgap/basic.expect

@@ -0,0 +1,19 @@
+# Initializing GAP...
+
+gap> 1+2+3;
+6
+gap> g:=FreeGroup(2);
+<free group on the generators [ f1, f2 ]>
+gap> a:=g.1;
+f1
+gap> b:=g.2;
+f2
+gap> lis:=[a^2, a^2, b*a];
+[ f1^2, f1^2, f2*f1 ]
+gap> h:=g/lis;
+<fp group on the generators [ f1, f2 ]>
+gap> c:=h.1;
+f1
+gap> Set([1..1000000], i->Order(c));
+[ 2 ]
+# done