jdk/src/solaris/native/sun/awt/awt_DataTransferer.c

/*
 * Copyright 2000-2005 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

#ifdef HEADLESS
    #error This file should not be included in headless library
#endif

#include "awt_p.h"
#include <X11/Intrinsic.h>
#include <X11/Xutil.h>

#include <sys/utsname.h>

#include <jni.h>
#include <jni_util.h>

#include "sun_awt_datatransfer_DataTransferer.h"
#include "sun_awt_motif_MDataTransferer.h"

#include "awt_XmDnD.h"
#include "awt_DataTransferer.h"

static jclass string;

XContext awt_convertDataContext = 0;

Atom XA_TARGETS;

extern struct X11GraphicsConfigIDs x11GraphicsConfigIDs;

typedef enum {
    SelectionPending,
    SelectionSuccess,
    SelectionFailure,
    SelectionOwnerTimedOut
} SelectionStatus;

/* Should only be accessed by the current owner of AWT_LOCK. */
static SelectionStatus globalSelectionStatus = SelectionPending;

static SelectionStatus get_selection_status() {
    return globalSelectionStatus;
}

static void set_selection_status(SelectionStatus status) {
    globalSelectionStatus = status;
}

static void
selection_request_filter(Widget widget, XtPointer closure, XEvent *event,
                         Boolean *cont) {
    if (event->type == SelectionRequest) {
        Window awt_root_window = XtWindow(awt_root_shell);
        Atom selection = event->xselectionrequest.selection;
        Window owner = XGetSelectionOwner(event->xany.display, selection);

        if (owner != awt_root_window) {
            XSelectionEvent notify;

            notify.type = SelectionNotify;
            notify.display = event->xselectionrequest.display;
            notify.requestor = event->xselectionrequest.requestor;
            notify.selection = event->xselectionrequest.selection;
            notify.time = event->xselectionrequest.time;
            notify.target = event->xselectionrequest.target;
            notify.property = None;

            XSendEvent(notify.display, notify.requestor, False,
                       (unsigned long)0, (XEvent*)&notify);
            *cont = False;
        }
    }
}

/**
 * global function to initialize this client as a Dynamic-only app.
 *
 * gets called once during toolkit initialization.
 */

void awt_initialize_DataTransferer() {
    JNIEnv* env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
    jclass stringClassLocal = NULL;

    DASSERT(string == NULL);

    stringClassLocal = (*env)->FindClass(env, "java/lang/String");

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
        DASSERT(False);
    }

    if (JNU_IsNull(env, stringClassLocal)) return;

    string = (*env)->NewGlobalRef(env, stringClassLocal); /* never freed! */
    (*env)->DeleteLocalRef(env, stringClassLocal);

    if (JNU_IsNull(env, string)) {
        JNU_ThrowOutOfMemoryError(env, "");
        return;
    }

    DASSERT(awt_convertDataContext == 0);
    awt_convertDataContext = XUniqueContext();
    DASSERT(awt_convertDataContext != 0);

    /*
     * Fixes for 4513976 and 4818143.
     */
    XtAppSetSelectionTimeout(awt_appContext,
            JNU_CallStaticMethodByName(env, NULL, "sun/awt/UNIXToolkit",
                                       "getDatatransferTimeout", "()I").i);

    /*
     * Xt selection machinery doesn't respond to SelectionRequests if the
     * event arrives on a widget that is not the current selection owner.
     * This can happen if XtDisownSelection was called when SelectionRequest was
     * already on the native queue.
     * If the requestor is another JVM, it hangs for the selection timeout
     * as SelectionNotify is never sent.
     * We install an event handler that filters out SelectionRequests if the
     * awt_root_shell is not the current selection owner.
     */
    XtAddEventHandler(awt_root_shell, (EventMask)0, True,
                      selection_request_filter, NULL);

    XA_TARGETS = XInternAtom(awt_display, "TARGETS", False);
}

/*
 * Single routine to convert to target FILE_NAME or _DT_FILENAME
 */
Boolean
convertFileType(jbyteArray data, Atom * type, XtPointer * value,
                unsigned long *length, int32_t *format)
{
    /*
     * Convert the internal representation to an File Name.
     * The data passed is an array of
     * null separated bytes. Each series of bytes is a string
     * that is then converted to an XString which are then put
     * into an XStringList and put into an XTextProperty for
     * usage in other programs.
     *
     * It would be desireable to have dataConvert to this conversion
     * but it isn't possible to return a byte array that represents
     * the XTextProperty.
     */

    JNIEnv*       env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
    jboolean      isCopy=JNI_FALSE;
    XTextProperty tp;
    jsize         len;
    jsize         strings = 0;
    jsize         i;
    char**        stringList;
    Status        s;
    jbyte*        bytes;
    char*         start;
    size_t        slen;
    char*         utf;

    if ((*env)->PushLocalFrame(env, 16) < 0) {
        return False;
    }

    /* convert the data to an Array of Byte Elements */
    bytes = (*env)->GetByteArrayElements(env, data, &isCopy);
    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
        (*env)->PopLocalFrame(env, NULL);
        return False;
    }

    if (JNU_IsNull(env, bytes)) {
        (*env)->PopLocalFrame(env, NULL);
        return False;
    }

    /* Get the length of the area */
    len = (*env)->GetArrayLength(env, data);
    if (len == 0) {
        (*env)->ReleaseByteArrayElements(env, data, bytes, JNI_ABORT);
        (*env)->PopLocalFrame(env, NULL);
        return False;
    }

    /*
     * determine the number of lists. The byteArray is null separated list of
     * strings.
     */
    for (i = 0; i < len; i++) {
        if (bytes[i] == '\0') {
            strings++;
        }
    }

    /* Allocate an X11 string list */
    stringList = (char **)XtCalloc(strings, sizeof(char *));
    if (stringList == (char**)NULL) {
        (*env)->ReleaseByteArrayElements(env, data, bytes, JNI_ABORT);
        (*env)->PopLocalFrame(env, NULL);
        return False;
    }

    for (i = 0; i < strings; i++) {
        if (i == 0) {
            start = (char*)bytes;
        } else {
            start = (char*)&bytes[slen];
        }

        /*
         * if start is a NULL we're at the end of the list
         * We'll just a have null entry on the end of the list
         */
        if (start[0] == '\0') {
            stringList[i] = NULL;
            continue;
        }
        slen = strlen(start) + 1;

        stringList[i] = (char*)XtCalloc(slen, sizeof(char));

        if (stringList[i] == (char *)NULL) {
            jsize j;

            (*env)->ReleaseByteArrayElements(env, data, bytes, JNI_ABORT);

            for (j = 0; j < i; j++) {
                XtFree((void *)stringList[j]);
            }

            (*env)->PopLocalFrame(env, NULL);

            return False;
        }

        memcpy((void *)stringList[i], (const void*)start, slen);
    }

    (*env)->ReleaseByteArrayElements(env, data, bytes, JNI_ABORT);
    s = XStringListToTextProperty(stringList, strings, &tp);

    /* free the strings that were created */
    for (i = 0; i < strings; i++) {
        if (stringList[i] != NULL) {
            XtFree((void*)stringList[i]);
        }
    }

    XtFree((void*)stringList);

    if (s == 0) {
        (*env)->PopLocalFrame(env, NULL);
        return False;
    }

    *value = (XtPointer)XtCalloc(tp.nitems, sizeof(char));

    if (*value == (XtPointer)NULL) {
        XFree((void*)tp.value);

        (*env)->PopLocalFrame(env, NULL);

        return False;
    }

    memcpy((void *)(*value), (const void *)tp.value, tp.nitems);

    XFree((void*)tp.value);

    *length = tp.nitems;
    *type   = tp.encoding;
    *format = tp.format;
    (*env)->PopLocalFrame(env, NULL);
    return True;
}

/*
 * Class:     sun_awt_motif_MDataTransferer
 * Method:    getAtomForTarget
 * Signature: (Ljava/lang/String;)J
 */

JNIEXPORT jlong JNICALL
Java_sun_awt_motif_MDataTransferer_getAtomForTarget(JNIEnv *env,
                                                    jclass cls,
                                                    jstring targetString)
{
    Atom target;
    char *target_str;

    if (JNU_IsNull(env, targetString)) {
        JNU_ThrowNullPointerException(env, "NullPointerException");
        return -1;
    }
    target_str = (char *) JNU_GetStringPlatformChars(env, targetString, NULL);

    AWT_LOCK();

    target = XInternAtom(awt_display, target_str, False);

    AWT_UNLOCK();

    JNU_ReleaseStringPlatformChars(env, targetString,
                                   (const char *) target_str);
    return target;
}

/*
 * Class:     sun_awt_motif_MDataTransferer
 * Method:    getTargetNameForAtom
 * Signature: (J)Ljava/lang/String;
 */

JNIEXPORT jstring JNICALL
Java_sun_awt_motif_MDataTransferer_getTargetNameForAtom(JNIEnv *env,
                                                        jclass cls,
                                                        jlong atom)
{
    jstring targetString;
    char *name;

    AWT_LOCK();

    name = XGetAtomName(awt_display, (Atom) atom);

    if (name == NULL) {
        JNU_ThrowNullPointerException(env, "Failed to retrieve atom name.");
        AWT_UNLOCK();
        return NULL;
    }

    targetString = (*env)->NewStringUTF(env, (const char *)name);

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
        XFree (name);
        AWT_UNLOCK();
        return NULL;
    }

    if (JNU_IsNull(env, targetString)) {
        JNU_ThrowNullPointerException(env, "Failed to create a string.");
        XFree (name);
        AWT_UNLOCK();
        return NULL;
    }

    XFree (name);

    AWT_UNLOCK();
    return targetString;
}

/*
 * Class:     sun_awt_datatransfer_DataTransferer
 * Method:    dragQueryFile
 * Signature: ([B)[Ljava/lang/String;
 *
 * This method converts a byte array that came from File most likely from a
 * drag operation into a String array.
 */

JNIEXPORT jobjectArray JNICALL
Java_sun_awt_motif_MDataTransferer_dragQueryFile
    (JNIEnv *env, jobject this, jbyteArray bytes)
{
    XTextProperty tp;
    jbyte         *value;

    char**        strings  = (char **)NULL;
    int32_t       nstrings = 0;
    jobject       filenames;
    jobject       ret = NULL;
    int32_t       i;
    jsize         len;
    jboolean      isCopy=JNI_FALSE;

    /*
     * If the length of the byte array is 0 just return a null
     */
    len = (*env)->GetArrayLength(env, bytes);
    if (len == 0) {
        return NULL;
    }

    value = (*env)->GetByteArrayElements(env, bytes, &isCopy);
    if (JNU_IsNull(env, value)) {
        return NULL;
    }

    AWT_LOCK();

    tp.encoding = XInternAtom(awt_display, "STRING", False);
    tp.value    = (unsigned char *)value;
    tp.nitems   = len;
    tp.format   = 8;

    /*
     * Convert the byte stream into a list of X11 strings
     */
    if (XTextPropertyToStringList(&tp, &strings, &nstrings) == 0 ||
        nstrings == 0)
        {
            (*env)->ReleaseByteArrayElements(env, bytes, value, JNI_ABORT);
            AWT_UNLOCK();
            return NULL;
        }

    (*env)->ReleaseByteArrayElements(env, bytes, value, JNI_ABORT);

    filenames = (*env)->NewObjectArray(env, nstrings, string, NULL);

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
        goto wayout;
    }

    if (JNU_IsNull(env, filenames)) {
        goto wayout;
    }

    /*
     * Actuall conversion code per X11 String
     */
    for (i = 0; i < nstrings; i++) {
        jstring string = (*env)->NewStringUTF(env,
                                              (const char *)strings[i]);
        if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
            (*env)->ExceptionDescribe(env);
            (*env)->ExceptionClear(env);
            goto wayout;
        }

        if (JNU_IsNull(env, string)) {
            goto wayout;
        }

        (*env)->SetObjectArrayElement(env, filenames, i, string);

        if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
            (*env)->ExceptionDescribe(env);
            (*env)->ExceptionClear(env);
            goto wayout;
        }

        (*env)->DeleteLocalRef(env, string);
    }

    ret = filenames;
 wayout:
    /*
     * Clean up and return
     */
    XFreeStringList(strings);
    AWT_UNLOCK();
    return ret;
}

DECLARE_JAVA_CLASS(dataTransfererClazz, "sun/awt/datatransfer/DataTransferer")

/**
 * Returns a local reference to the singleton DataTransferer instance.
 * The caller should delete the reference when done.
 */
static jobject
get_data_transferer(JNIEnv* env) {
    jobject transferer = NULL;

    DECLARE_STATIC_OBJECT_JAVA_METHOD(getInstanceMethodID, dataTransfererClazz,
                                     "getInstance",
                                     "()Lsun/awt/datatransfer/DataTransferer;");

    transferer = (*env)->CallStaticObjectMethod(env, clazz, getInstanceMethodID);

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
    }

    DASSERT(!JNU_IsNull(env, transferer));

    return transferer;
}

static jobject
call_convertData(JNIEnv* env, jobject source, jobject contents, jlong format,
                 jobject formatMap) {
    jobject transferer = get_data_transferer(env);
    jobject ret = NULL;
    DECLARE_OBJECT_JAVA_METHOD(convertDataMethodID, dataTransfererClazz,
                               "convertData",
                               "(Ljava/lang/Object;Ljava/awt/datatransfer/Transferable;JLjava/util/Map;Z)[B");

    ret = (*env)->CallObjectMethod(env, transferer, convertDataMethodID,
                                   source, contents, format, formatMap,
                                   awt_currentThreadIsPrivileged(env));

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
    }

    (*env)->DeleteLocalRef(env, transferer);

    return ret;
}

static void
process_convert_data_requests() {
    JNIEnv* env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_4);
    jobject transferer = get_data_transferer(env);

    DECLARE_VOID_JAVA_METHOD(processDataConversionRequestsMethodID,
                             dataTransfererClazz,
                             "processDataConversionRequests",
                             "()V");

    (*env)->CallVoidMethod(env, transferer,
                           processDataConversionRequestsMethodID);

    if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
    }

    (*env)->DeleteLocalRef(env, transferer);
}

Boolean
awt_convertData(Widget w, Atom * selection, Atom * target, Atom * type,
                XtPointer * value, unsigned long *length, int32_t *format) {
    JNIEnv*  env  = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
    Display* dpy = XtDisplay(w);
    awt_convertDataCallbackStruct* structPtr = NULL;

    if (XFindContext(dpy, *selection, awt_convertDataContext,
                     (XPointer*)&structPtr) == XCNOMEM || structPtr == NULL) {
        return False;
    }

    if ((*env)->PushLocalFrame(env, 2) < 0) {
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
        return False;
    }

    if (*target == XA_TARGETS) {
        jlongArray formats = structPtr->formats;
        jsize      count;
        jlong*     targets;
        jboolean   isCopy;

#ifndef _LP64 /* Atom and jlong are different sizes in the 32-bit build */
        Atom*      aValue;
        jlong*     saveTargets;
        jsize      i;
#endif

        if (JNU_IsNull(env, formats)) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }

        count = (*env)->GetArrayLength(env, formats);
        if (count == 0) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }

        targets = (*env)->GetLongArrayElements(env, formats, &isCopy);

        *type = XA_ATOM;
        *format = 32;

#ifdef _LP64
        *value = XtMalloc(count * sizeof(Atom));
        memcpy((void *)*value, (void *)targets, count * sizeof(Atom));
#else
        *value = aValue = (Atom *)XtMalloc(count * sizeof(Atom));
        saveTargets = targets;
        for (i = 0; i < count; i++, aValue++, targets++) {
            *aValue = (Atom)*targets;
        }
        targets = saveTargets;
#endif
        (*env)->ReleaseLongArrayElements(env, formats, targets, JNI_ABORT);

        *length = count;

    } else if (*target == XInternAtom(dpy, _XA_DELETE, False)) {

        /*
         * acknowledge the DELETE target here ... the "delete" semantic
         * of move will take place after the drop is complete.
         */

        *type   = XInternAtom(dpy, _XA_NULL, False);
        *length = 0;
        *value  = (XtPointer)NULL;
        /* Uninitialized format can cause crash in Xt conversion code. */
        *format = 8;
    } else if (*target == XInternAtom(dpy, _XA_HOSTNAME, False)) {
        struct utsname name;
        XTextProperty  tp;

        uname(&name);

        if (!XStringListToTextProperty((char **)&name.nodename, 1, &tp)) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }

        *value = (XtPointer)XtCalloc(tp.nitems, sizeof(char));

        memcpy((void *)*value, (const void *)tp.value, tp.nitems);

        XFree((void *)tp.value);

        *type   = tp.encoding;
        *length = tp.nitems + 1;
        *format = tp.format;
    } else if (*target == XInternAtom(dpy, _XA_FILENAME, False) ||
               *target == XInternAtom(dpy, _DT_FILENAME, False)) {

        /*
         * Convert the internal representation to an File Name.
         * The data returned from dataConvert is a an array of
         * null separated bytes. Each series of bytes is a string
         * that is then converted to an XString which are then put
         * into an XStringList and put into an XTextProperty for
         * usage in other programs.
         *
         * It would be desireable to have dataConvert to this conversion
         * but it isn't possible to return a byte array that represents
         * the XTextProperty.
         */
        jbyteArray    data;

        /*
         * Fix for 4513976.
         * Type None should be used instead of XT_CONVERT_FAIL
         * to report conversion failure.
         */
        /*  assume forthcoming error */
        *type   = None;
        *value  = (XtPointer)NULL;
        *length = 0;
        *format = 8;

        data = call_convertData(env, structPtr->source, structPtr->transferable,
                                (jlong)*target, structPtr->formatMap);

        /* error test */
        if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
            (*env)->ExceptionDescribe(env);
            (*env)->ExceptionClear(env);
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }
        if (JNU_IsNull(env, data)) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }

        if (convertFileType(data, type, value, length, format) == False) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }
    } else {
        jbyteArray bytes = NULL;
        jbyte*     copy = NULL;

        /*
         * Fix for 4513976.
         * Type None should be used instead of XT_CONVERT_FAIL
         * to report conversion failure.
         */
        *type   = None; /* assume forthcoming error */
        *value  = (XtPointer)NULL;
        *length = 0;
        *format = 8;

        bytes = call_convertData(env, structPtr->source, structPtr->transferable,
                                 (jlong)*target, structPtr->formatMap);

        if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
            (*env)->ExceptionDescribe(env);
            (*env)->ExceptionClear(env);
            (*env)->PopLocalFrame(env, NULL);
            return False;
        }

        if (bytes == NULL) {
            (*env)->PopLocalFrame(env, NULL);
            return False;
        } else {
            jsize len = (*env)->GetArrayLength(env, bytes);

            if (len == 0) {
                *type   = *target;
                *format = 8;
                (*env)->PopLocalFrame(env, NULL);
                return True;
            }

            copy = (jbyte*)XtCalloc(1, len * sizeof(jbyte));
            if (copy == (jbyte*)NULL) {
                JNU_ThrowOutOfMemoryError(env, "OutOfMemoryError");
                (*env)->PopLocalFrame(env, NULL);
                return False;
            }

            (*env)->GetByteArrayRegion(env, (jbyteArray)bytes, 0, len, copy);

            if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
                (*env)->ExceptionDescribe(env);
                (*env)->ExceptionClear(env);
                XtFree((void *)copy);
                (*env)->PopLocalFrame(env, NULL);
                return False;
            }

            *value  = (XtPointer)copy;
            *type   = *target;
            *length = len;
            *format = 8;
        }
    }

    (*env)->PopLocalFrame(env, NULL);
    return True;
}


jlongArray
getSelectionTargetsHelper(JNIEnv* env, XtPointer value, unsigned long length)
{
    Atom* targets = (Atom*)value;
    jlongArray targetArray = NULL;
    jlong* checkedTargets = NULL;
    size_t count = 0, i = 0, j = 0;

    /* Get rid of zero atoms if there are any. */
    for (; i < length; i++) {
        if (targets[i] != 0) {
            count++;
        }
    }
    checkedTargets = calloc(count, sizeof(jlong));
    if (checkedTargets == NULL) {
        JNU_ThrowOutOfMemoryError(env, "");
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
    } else {
        for (i = 0; i < length; i++) {
            if (targets[i] != 0) {
                checkedTargets[j++] = targets[i];
            }
        }

        DASSERT(j == count);

        if ((*env)->EnsureLocalCapacity(env, 1) >= 0) {

            targetArray = (*env)->NewLongArray(env, count);

            if (!JNU_IsNull(env, targetArray)) {
                (*env)->SetLongArrayRegion(env, targetArray, 0, count,
                                           checkedTargets);

                if ((*env)->ExceptionCheck(env)) {
                    (*env)->ExceptionDescribe(env);
                    (*env)->ExceptionClear(env);

                    (*env)->DeleteLocalRef(env, targetArray);
                    targetArray = NULL;
                }
            }
        }
        free(checkedTargets);
    }

    return targetArray;
}

static void
get_selection_targets_callback(Widget w, XtPointer client_data, Atom* selection,
                               Atom* type, XtPointer value,
                               unsigned long* length, int32_t* format) {
    JNIEnv *env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
    jobject* pReturnArray = (jobject*)client_data;
    SelectionStatus status = SelectionFailure;

    /*
     * It is highly unlikely that TARGETS will ever be passed even though that
     * was what was requested. However, XA_ATOM ("ATOM") is likely.
     * Actually they are the same so treat them as such. See XToolKit
     * Intrinsic Manual on XtSelectionCallbackProc for more details on type.
     */
    if (*type == XA_TARGETS || *type == XA_ATOM) {
        jlongArray targetArray = getSelectionTargetsHelper(env, value, *length);
        if (!JNU_IsNull(env, targetArray)) {
            *pReturnArray = (*env)->NewGlobalRef(env, targetArray);
            status = SelectionSuccess;
            (*env)->DeleteLocalRef(env, targetArray);
        }
    } else if (*type == XT_CONVERT_FAIL) {
        status = SelectionOwnerTimedOut;
    } else {
        /*
         * A part of the fix for 4259272.
         * Actually Xt Intrinsics says about XtSelectionCallback that
         * "if there is no owner for the specified selection, or that owner
         * cannot convert the selected data to the requested type, then this
         * callback is called with value NULL and length zero".
         * But we report success if type is not TARGETS, XA_ATOM or XT_CONVERT_FAIL,
         * and we should not change this behaviour. We just return zero-length
         * array instead of null, because null denotes that we could not get
         * selection targets at the time of tracking changes of available on
         * the selection data flavors.
         */
        jlongArray targetArray = (*env)->NewLongArray(env, 0);
        *pReturnArray = (*env)->NewGlobalRef(env, targetArray);
        /*
         * Fix for 4655996.
         * Report success if there is no owner for this selection or the owner
         * fails to provide target types.
         */
        status = SelectionSuccess;
        (*env)->DeleteLocalRef(env, targetArray);
    }

    if (value != NULL) {
        XtFree(value);
        value = NULL;
    }

    set_selection_status(status);
}

static void
get_selection_data_callback(Widget w, XtPointer client_data, Atom * selection,
                            Atom * type, XtPointer value, unsigned long *length,
                            int32_t *format) {
    JNIEnv *env = (JNIEnv *)JNU_GetEnv(jvm, JNI_VERSION_1_2);
    jobject* pData = (jobject*)client_data;
    SelectionStatus status = SelectionFailure;

    if (*type == XT_CONVERT_FAIL) {
        status = SelectionOwnerTimedOut;
    } else if (*type != None) {
        if ((*env)->EnsureLocalCapacity(env, 1) >= 0) {
            jsize size = (*length <= INT_MAX) ? *length : INT_MAX;
            jbyteArray array = (*env)->NewByteArray(env, size);

            if (!JNU_IsNull(env, array)) {
                (*env)->SetByteArrayRegion(env, array, 0, size, (jbyte*)value);
                if ((*env)->ExceptionCheck(env) == JNI_TRUE) {
                    (*env)->ExceptionDescribe(env);
                    (*env)->ExceptionClear(env);
                } else {
                    *pData = (*env)->NewGlobalRef(env, array);
                    status = SelectionSuccess;
                }

                (*env)->DeleteLocalRef(env, array);
            }
        }
    }

    if (value != NULL) {
        XtFree(value);
        value = NULL;
    }

    set_selection_status(status);
}

static int32_t
wait_for_selection_event(void *data) {
    process_convert_data_requests();
    return get_selection_status() != SelectionPending;
}

jlongArray
get_selection_targets(JNIEnv *env, Atom selection, Time time_stamp) {
    jlongArray ret     = NULL;
    jlongArray targets = NULL;
    SelectionStatus status = SelectionPending;

    AWT_LOCK();

    XtAppSetSelectionTimeout(awt_appContext,
            JNU_CallStaticMethodByName(env, NULL, "sun/awt/UNIXToolkit",
                                       "getDatatransferTimeout", "()I").i);

    set_selection_status(SelectionPending);
    XtGetSelectionValue(awt_root_shell, selection, XA_TARGETS,
                        get_selection_targets_callback, (XtPointer)&targets,
                        time_stamp);

    awt_MToolkit_modalWait(wait_for_selection_event, NULL);
    status = get_selection_status();

    AWT_FLUSH_UNLOCK();

    if (!JNU_IsNull(env, targets)) {
        ret = (*env)->NewLocalRef(env, targets);
        (*env)->DeleteGlobalRef(env, targets);
    }

    switch (status) {
    case SelectionSuccess:
        break;
    case SelectionFailure:
        JNU_ThrowByName(env, "java/lang/IllegalStateException",
                        "Failed to get selection targets");
        break;
    case SelectionOwnerTimedOut:
        // return an empty array of targets if the selection owner timed out
        ret = (*env)->NewLongArray(env, 0);
        break;
    default:
        JNU_ThrowByName(env, "java/lang/IllegalStateException",
                        "Unexpected selection status");
        break;
    }

    return ret;
}

jbyteArray
get_selection_data(JNIEnv *env, Atom selection, Atom target, Time time_stamp) {
    jbyteArray ret    = NULL;
    jbyteArray data   = NULL;
    SelectionStatus status = SelectionPending;

    AWT_LOCK();

    XtAppSetSelectionTimeout(awt_appContext,
            JNU_CallStaticMethodByName(env, NULL, "sun/awt/UNIXToolkit",
                                       "getDatatransferTimeout", "()I").i);

    set_selection_status(SelectionPending);
    XtGetSelectionValue(awt_root_shell, selection, target,
                        get_selection_data_callback,
                        (XtPointer)&data, time_stamp);

    awt_MToolkit_modalWait(wait_for_selection_event, NULL);
    status = get_selection_status();

    AWT_FLUSH_UNLOCK();

    if (!JNU_IsNull(env, data)) {
        ret = (*env)->NewLocalRef(env, data);
        (*env)->DeleteGlobalRef(env, data);
    }

    switch (status) {
    case SelectionSuccess:
        break;
    case SelectionFailure:
        JNU_ThrowIOException(env, "Failed to get selection data");
        break;
    case SelectionOwnerTimedOut:
        JNU_ThrowIOException(env, "Selection owner timed out");
        break;
    default:
        JNU_ThrowIOException(env, "Unexpected selection status");
        break;
    }

    return ret;
}

void
awt_cleanupConvertDataContext(JNIEnv *env, Atom selectionAtom) {
    awt_convertDataCallbackStruct* structPtr = NULL;

    if (XFindContext(awt_display, selectionAtom, awt_convertDataContext,
                     (XPointer*)&structPtr) == 0 && structPtr != NULL) {

        (*env)->DeleteGlobalRef(env, structPtr->source);
        (*env)->DeleteGlobalRef(env, structPtr->transferable);
        (*env)->DeleteGlobalRef(env, structPtr->formatMap);
        (*env)->DeleteGlobalRef(env, structPtr->formats);
        free(structPtr);
    }
    /*
     * Xlib Programming Manual says that it is better to erase
     * the current entry with XDeleteContext() before XSaveContext().
     */
    XDeleteContext(awt_display, selectionAtom, awt_convertDataContext);
    if (XSaveContext(awt_display, selectionAtom, awt_convertDataContext,
                     (XPointer)NULL) == XCNOMEM) {
        JNU_ThrowInternalError(env, "XError");
        (*env)->ExceptionDescribe(env);
        (*env)->ExceptionClear(env);
    }
}

static Bool exitSecondaryLoop = True;

/*
 * This predicate procedure allows the Toolkit thread to process specific events
 * while it is blocked waiting for the event dispatch thread to process
 * a SunDropTargetEvent. We need this to prevent deadlock when the client code
 * processing SunDropTargetEvent sets or gets the contents of the system
 * clipboard/selection. In this case the event dispatch thread waits for the
 * Toolkit thread to process PropertyNotify or SelectionNotify events.
 */
static Bool
secondary_loop_event(Display* dpy, XEvent* event, char* arg) {
    return (event->type == SelectionNotify ||
            event->type == SelectionClear  ||
            event->type == PropertyNotify) ? True : False;
}


JNIEXPORT void JNICALL
Java_sun_awt_motif_MToolkitThreadBlockedHandler_enter(JNIEnv *env, jobject this) {
    DASSERT(exitSecondaryLoop && awt_currentThreadIsPrivileged(env));
    exitSecondaryLoop = False;
    while (!exitSecondaryLoop) {
        XEvent event;
        while (XCheckIfEvent(awt_display, &event, secondary_loop_event, NULL)) {
            XtDispatchEvent(&event);
        }
        AWT_WAIT(AWT_DND_POLL_INTERVAL);
    }
}

JNIEXPORT void JNICALL
Java_sun_awt_motif_MToolkitThreadBlockedHandler_exit(JNIEnv *env, jobject this) {
    DASSERT(!exitSecondaryLoop && !awt_currentThreadIsPrivileged(env));
    exitSecondaryLoop = True;
    AWT_NOTIFY_ALL();
}