Java API for opening/closing SG databases

8 files changed, 259 insertions, 91 deletions

diff --git a/src/runtime/java/Makefile b/src/runtime/java/Makefile
index cb8000fd2..ccbd901e1 100644
--- a/src/runtime/java/Makefile
+++ b/src/runtime/java/Makefile
@@ -1,4 +1,4 @@
-C_SOURCES = jpgf.c jsg.c
+C_SOURCES = jpgf.c jsg.c jni_utils.c
 JAVA_SOURCES = $(wildcard org/grammaticalframework/pgf/*.java) \
                $(wildcard org/grammaticalframework/sg/*.java)
 
diff --git a/src/runtime/java/jni_utils.c b/src/runtime/java/jni_utils.c
new file mode 100644
index 000000000..64352e157
--- /dev/null
+++ b/src/runtime/java/jni_utils.c
@@ -0,0 +1,94 @@
+#include <jni.h>
+#include <gu/utf8.h>
+#include <gu/string.h>
+#include "jni_utils.h"
+#ifndef __MINGW32__
+#include <alloca.h>
+#else
+#include <malloc.h>
+#endif
+
+#define l2p(x) ((void*) (intptr_t) (x))
+#define p2l(x) ((jlong) (intptr_t) (x))
+
+jstring
+gu2j_string(JNIEnv *env, GuString s) {
+	const char* utf8 = s;
+	size_t len = strlen(s);
+
+	jchar* utf16 = alloca(len*sizeof(jchar));
+	jchar* dst   = utf16;
+	while (s-utf8 < len) {
+		GuUCS ucs = gu_utf8_decode((const uint8_t**) &s);
+
+		if (ucs <= 0xFFFF) {
+			*dst++ = ucs;
+		} else {
+			ucs -= 0x10000;
+			*dst++ = 0xD800+((ucs >> 10) & 0x3FF);
+			*dst++ = 0xDC00+(ucs & 0x3FF);
+		}
+	}
+
+	return (*env)->NewString(env, utf16, dst-utf16);
+}
+
+GuString
+j2gu_string(JNIEnv *env, jstring s, GuPool* pool) {
+	GuString str = (*env)->GetStringUTFChars(env, s, 0);
+	GuString copy = gu_string_copy(str, pool);
+	(*env)->ReleaseStringUTFChars(env, s, str);
+	return copy;
+}
+
+size_t
+gu2j_string_offset(GuString s, size_t offset) {
+	const char* utf8 = s;
+	size_t joffset = 0;
+	while (utf8-s < offset) {
+		gu_utf8_decode((const uint8_t**) &utf8);
+		joffset++;
+	}
+	return joffset;
+}
+
+size_t
+j2gu_string_offset(GuString s, size_t joffset) {
+	const char* utf8 = s;
+	while (joffset > 0) {
+		gu_utf8_decode((const uint8_t**) &utf8);
+		joffset--;
+	}
+	return utf8-s;
+}
+
+void*
+get_ref(JNIEnv *env, jobject self) {
+	jfieldID refId = (*env)->GetFieldID(env, (*env)->GetObjectClass(env, self), "ref", "J");
+	return l2p((*env)->GetLongField(env, self, refId));
+}
+
+void
+throw_jstring_exception(JNIEnv *env, const char* class_name, jstring msg)
+{
+	jclass exception_class = (*env)->FindClass(env, class_name);
+	if (!exception_class)
+		return;
+	jmethodID constrId = (*env)->GetMethodID(env, exception_class, "<init>", "(Ljava/lang/String;)V");
+	if (!constrId)
+		return;
+	jobject exception = (*env)->NewObject(env, exception_class, constrId, msg);
+	if (!exception)
+		return;
+	(*env)->Throw(env, exception);
+}
+
+void
+throw_string_exception(JNIEnv *env, const char* class_name, const char* msg)
+{
+	jstring jmsg = (*env)->NewStringUTF(env, msg);
+	if (!jmsg)
+		return;
+	throw_jstring_exception(env, class_name, jmsg);
+}
+
diff --git a/src/runtime/java/jni_utils.h b/src/runtime/java/jni_utils.h
new file mode 100644
index 000000000..c587346bc
--- /dev/null
+++ b/src/runtime/java/jni_utils.h
@@ -0,0 +1,28 @@
+#ifndef JNI_UTILS
+#define JNI_UTILS
+
+#define l2p(x) ((void*) (intptr_t) (x))
+#define p2l(x) ((jlong) (intptr_t) (x))
+
+jstring
+gu2j_string(JNIEnv *env, GuString s);
+
+GuString
+j2gu_string(JNIEnv *env, jstring s, GuPool* pool);
+
+size_t
+gu2j_string_offset(GuString s, size_t offset);
+
+size_t
+j2gu_string_offset(GuString s, size_t joffset);
+
+void*
+get_ref(JNIEnv *env, jobject self);
+
+void
+throw_jstring_exception(JNIEnv *env, const char* class_name, jstring msg);
+
+void
+throw_string_exception(JNIEnv *env, const char* class_name, const char* msg);
+
+#endif
diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index 875f41e80..db7765551 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -2,98 +2,9 @@
 #include <pgf/linearizer.h>
 #include <gu/mem.h>
 #include <gu/exn.h>
-#include <gu/utf8.h>
 #include <math.h>
 #include <jni.h>
-#ifndef __MINGW32__
-#include <alloca.h>
-#else
-#include <malloc.h>
-#endif
-
-#define l2p(x) ((void*) (intptr_t) (x))
-#define p2l(x) ((jlong) (intptr_t) (x))
-
-static jstring
-gu2j_string(JNIEnv *env, GuString s) {
-	const char* utf8 = s;
-	size_t len = strlen(s);
-
-	jchar* utf16 = alloca(len*sizeof(jchar));
-	jchar* dst   = utf16;
-	while (s-utf8 < len) {
-		GuUCS ucs = gu_utf8_decode((const uint8_t**) &s);
-
-		if (ucs <= 0xFFFF) {
-			*dst++ = ucs;
-		} else {
-			ucs -= 0x10000;
-			*dst++ = 0xD800+((ucs >> 10) & 0x3FF);
-			*dst++ = 0xDC00+(ucs & 0x3FF);
-		}
-	}
-
-	return (*env)->NewString(env, utf16, dst-utf16);
-}
-
-static GuString
-j2gu_string(JNIEnv *env, jstring s, GuPool* pool) {
-	GuString str = (*env)->GetStringUTFChars(env, s, 0);
-	GuString copy = gu_string_copy(str, pool);
-	(*env)->ReleaseStringUTFChars(env, s, str);
-	return copy;
-}
-
-static size_t
-gu2j_string_offset(GuString s, size_t offset) {
-	const char* utf8 = s;
-	size_t joffset = 0;
-	while (utf8-s < offset) {
-		gu_utf8_decode((const uint8_t**) &utf8);
-		joffset++;
-	}
-	return joffset;
-}
-
-static size_t
-j2gu_string_offset(GuString s, size_t joffset) {
-	const char* utf8 = s;
-	while (joffset > 0) {
-		gu_utf8_decode((const uint8_t**) &utf8);
-		joffset--;
-	}
-	return utf8-s;
-}
-
-static void*
-get_ref(JNIEnv *env, jobject self) {
-	jfieldID refId = (*env)->GetFieldID(env, (*env)->GetObjectClass(env, self), "ref", "J");
-	return l2p((*env)->GetLongField(env, self, refId));
-}
-
-static void
-throw_jstring_exception(JNIEnv *env, const char* class_name, jstring msg)
-{
-	jclass exception_class = (*env)->FindClass(env, class_name);
-	if (!exception_class)
-		return;
-	jmethodID constrId = (*env)->GetMethodID(env, exception_class, "<init>", "(Ljava/lang/String;)V");
-	if (!constrId)
-		return;
-	jobject exception = (*env)->NewObject(env, exception_class, constrId, msg);
-	if (!exception)
-		return;
-	(*env)->Throw(env, exception);
-}
-
-static void
-throw_string_exception(JNIEnv *env, const char* class_name, const char* msg)
-{
-	jstring jmsg = (*env)->NewStringUTF(env, msg);
-	if (!jmsg)
-		return;
-	throw_jstring_exception(env, class_name, jmsg);
-}
+#include "jni_utils.h"
 
 static JavaVM* cachedJVM;
 
diff --git a/src/runtime/java/jsg.c b/src/runtime/java/jsg.c
new file mode 100644
index 000000000..8f790505e
--- /dev/null
+++ b/src/runtime/java/jsg.c
@@ -0,0 +1,79 @@
+#include <jni.h>
+#include <sg/sg.h>
+#include "jni_utils.h"
+
+JNIEXPORT jobject JNICALL
+Java_org_grammaticalframework_sg_SG_openSG(JNIEnv *env, jclass cls, jstring path)
+{
+	GuPool* tmp_pool = gu_local_pool();
+
+	// Create an exception frame that catches all errors.
+	GuExn* err = gu_exn(tmp_pool);
+
+	const char *fpath = (*env)->GetStringUTFChars(env, path, 0); 
+
+	// Read the PGF grammar.
+	SgSG* sg = sg_open(fpath, err);
+
+	(*env)->ReleaseStringUTFChars(env, path, fpath);
+
+	if (!gu_ok(err)) {
+		GuString msg;
+		if (gu_exn_caught(err, SgError)) {
+			msg = (GuString) gu_exn_caught_data(err);
+		} else {
+			msg = "The database cannot be opened";
+		}
+		throw_string_exception(env, "org/grammaticalframework/sg/SGError", msg);
+		gu_pool_free(tmp_pool);
+		return NULL;
+	}
+
+	gu_pool_free(tmp_pool);
+
+	jmethodID constrId = (*env)->GetMethodID(env, cls, "<init>", "(J)V");
+	return (*env)->NewObject(env, cls, constrId, p2l(sg));
+}
+
+JNIEXPORT void JNICALL
+Java_org_grammaticalframework_sg_SG_close(JNIEnv *env, jobject self)
+{
+	GuPool* tmp_pool = gu_local_pool();
+
+	// Create an exception frame that catches all errors.
+	GuExn* err = gu_exn(tmp_pool);
+
+	sg_close(get_ref(env, self), err);
+	if (!gu_ok(err)) {
+		GuString msg;
+		if (gu_exn_caught(err, SgError)) {
+			msg = (GuString) gu_exn_caught_data(err);
+		} else {
+			msg = "The database cannot be closed";
+		}
+		throw_string_exception(env, "org/grammaticalframework/sg/SGError", msg);
+		gu_pool_free(tmp_pool);
+		return;
+	}
+
+	gu_pool_free(tmp_pool);
+}
+
+JNIEXPORT jobject JNICALL
+Java_org_grammaticalframework_sg_SG_queryTriple(JNIEnv *env, jobject self,
+                                                jobject subj,
+                                                jobject pred,
+                                                jobject obj)
+{
+	return NULL;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_org_grammaticalframework_sg_TripleResult_hasNext(JNIEnv *env, jobject self)
+{
+}
+
+JNIEXPORT void JNICALL
+Java_org_grammaticalframework_sg_TripleResult_close(JNIEnv *env, jobject self)
+{
+}
diff --git a/src/runtime/java/org/grammaticalframework/sg/SG.java b/src/runtime/java/org/grammaticalframework/sg/SG.java
new file mode 100644
index 000000000..631b38ff7
--- /dev/null
+++ b/src/runtime/java/org/grammaticalframework/sg/SG.java
@@ -0,0 +1,22 @@
+package org.grammaticalframework.sg;
+
+import java.io.Closeable;
+import org.grammaticalframework.pgf.Expr;
+
+public class SG implements Closeable {
+	public static native SG openSG(String path);
+	public native void close();
+	public native TripleResult queryTriple(Expr subj, Expr pred, Expr obj);
+
+	//////////////////////////////////////////////////////////////////
+	// private stuff
+	private long ref;
+
+	private SG(long ref) {
+		this.ref  = ref;
+	}
+
+	static {
+		System.loadLibrary("jpgf");
+	}
+}
diff --git a/src/runtime/java/org/grammaticalframework/sg/SGError.java b/src/runtime/java/org/grammaticalframework/sg/SGError.java
new file mode 100644
index 000000000..0de876bd4
--- /dev/null
+++ b/src/runtime/java/org/grammaticalframework/sg/SGError.java
@@ -0,0 +1,9 @@
+package org.grammaticalframework.sg;
+
+public class SGError extends RuntimeException {
+	private static final long serialVersionUID = -6098784400143861939L;
+
+	public SGError(String message) {
+		super(message);
+	}
+}
diff --git a/src/runtime/java/org/grammaticalframework/sg/TripleResult.java b/src/runtime/java/org/grammaticalframework/sg/TripleResult.java
new file mode 100644
index 000000000..59a0ddb81
--- /dev/null
+++ b/src/runtime/java/org/grammaticalframework/sg/TripleResult.java
@@ -0,0 +1,25 @@
+package org.grammaticalframework.sg;
+
+import java.io.Closeable;
+import org.grammaticalframework.pgf.Expr;
+
+public class TripleResult implements Closeable {
+	private Expr subj;
+	private Expr pred;
+	private Expr obj;
+
+	public native boolean hasNext();
+	public native void close();
+	
+	public Expr getSubject() {
+		return subj;
+	}
+
+	public Expr getPredicate() {
+		return pred;
+	}
+
+	public Expr getObject() {
+		return obj;
+	}
+}