Java example source code file (GnomeFileTypeDetector.c)

This example Java source code file (GnomeFileTypeDetector.c) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

g_file_attribute_standard_content_type, g_file_query_info_none, gcancellable, gerror, gfile, gfileinfo, gfilequeryinfoflags, jni_false, jni_true, jnicall, jnienv, jniexport, null, rtld_lazy

The GnomeFileTypeDetector.c Java example source code

/*
 * Copyright (c) 2008, 2012, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include "jni.h"
#include "jni_util.h"
#include "jvm.h"
#include "jlong.h"

#include <stdlib.h>
#include <dlfcn.h>

#ifdef __solaris__
#include <strings.h>
#endif

#if defined(__linux__)
#include <string.h>
#endif

/* Definitions for GIO */

#define G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE "standard::content-type"

typedef void* gpointer;
typedef struct _GFile GFile;
typedef struct _GFileInfo GFileInfo;
typedef struct _GCancellable GCancellable;
typedef struct _GError GError;

typedef enum {
  G_FILE_QUERY_INFO_NONE = 0
} GFileQueryInfoFlags;

typedef void (*g_type_init_func)(void);
typedef void (*g_object_unref_func)(gpointer object);
typedef GFile* (*g_file_new_for_path_func)(const char* path);
typedef GFileInfo* (*g_file_query_info_func)(GFile *file,
    const char *attributes, GFileQueryInfoFlags flags,
    GCancellable *cancellable, GError **error);
typedef char* (*g_file_info_get_content_type_func)(GFileInfo *info);

static g_type_init_func g_type_init;
static g_object_unref_func g_object_unref;
static g_file_new_for_path_func g_file_new_for_path;
static g_file_query_info_func g_file_query_info;
static g_file_info_get_content_type_func g_file_info_get_content_type;


/* Definitions for GNOME VFS */

typedef int gboolean;

typedef gboolean (*gnome_vfs_init_function)(void);
typedef const char* (*gnome_vfs_mime_type_from_name_function)
    (const char* filename);

static gnome_vfs_init_function gnome_vfs_init;
static gnome_vfs_mime_type_from_name_function gnome_vfs_mime_type_from_name;


#include "sun_nio_fs_GnomeFileTypeDetector.h"


JNIEXPORT jboolean JNICALL
Java_sun_nio_fs_GnomeFileTypeDetector_initializeGio
    (JNIEnv* env, jclass this)
{
    void* gio_handle;

    gio_handle = dlopen("libgio-2.0.so", RTLD_LAZY);
    if (gio_handle == NULL) {
        gio_handle = dlopen("libgio-2.0.so.0", RTLD_LAZY);
        if (gio_handle == NULL) {
            return JNI_FALSE;
        }
    }

    g_type_init = (g_type_init_func)dlsym(gio_handle, "g_type_init");
    (*g_type_init)();

    g_object_unref = (g_object_unref_func)dlsym(gio_handle, "g_object_unref");

    g_file_new_for_path =
        (g_file_new_for_path_func)dlsym(gio_handle, "g_file_new_for_path");

    g_file_query_info =
        (g_file_query_info_func)dlsym(gio_handle, "g_file_query_info");

    g_file_info_get_content_type = (g_file_info_get_content_type_func)
        dlsym(gio_handle, "g_file_info_get_content_type");


    if (g_type_init == NULL ||
        g_object_unref == NULL ||
        g_file_new_for_path == NULL ||
        g_file_query_info == NULL ||
        g_file_info_get_content_type == NULL)
    {
        dlclose(gio_handle);
        return JNI_FALSE;
    }

    (*g_type_init)();
    return JNI_TRUE;
}

JNIEXPORT jbyteArray JNICALL
Java_sun_nio_fs_GnomeFileTypeDetector_probeUsingGio
    (JNIEnv* env, jclass this, jlong pathAddress)
{
    char* path = (char*)jlong_to_ptr(pathAddress);
    GFile* gfile;
    GFileInfo* gfileinfo;
    jbyteArray result = NULL;

    gfile = (*g_file_new_for_path)(path);
    gfileinfo = (*g_file_query_info)(gfile, G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
        G_FILE_QUERY_INFO_NONE, NULL, NULL);
    if (gfileinfo != NULL) {
        const char* mime = (*g_file_info_get_content_type)(gfileinfo);
        if (mime != NULL) {
            jsize len = strlen(mime);
            result = (*env)->NewByteArray(env, len);
            if (result != NULL) {
                (*env)->SetByteArrayRegion(env, result, 0, len, (jbyte*)mime);
            }
        }
        (*g_object_unref)(gfileinfo);
    }
    (*g_object_unref)(gfile);

    return result;
}

JNIEXPORT jboolean JNICALL
Java_sun_nio_fs_GnomeFileTypeDetector_initializeGnomeVfs
    (JNIEnv* env, jclass this)
{
    void* vfs_handle;

    vfs_handle = dlopen("libgnomevfs-2.so", RTLD_LAZY);
    if (vfs_handle == NULL) {
        vfs_handle = dlopen("libgnomevfs-2.so.0", RTLD_LAZY);
    }
    if (vfs_handle == NULL) {
        return JNI_FALSE;
    }

    gnome_vfs_init = (gnome_vfs_init_function)dlsym(vfs_handle, "gnome_vfs_init");
    gnome_vfs_mime_type_from_name = (gnome_vfs_mime_type_from_name_function)
        dlsym(vfs_handle, "gnome_vfs_mime_type_from_name");

    if (gnome_vfs_init == NULL ||
        gnome_vfs_mime_type_from_name == NULL)
    {
        dlclose(vfs_handle);
        return JNI_FALSE;
    }

    (*gnome_vfs_init)();
    return JNI_TRUE;
}

JNIEXPORT jbyteArray JNICALL
Java_sun_nio_fs_GnomeFileTypeDetector_probeUsingGnomeVfs
    (JNIEnv* env, jclass this, jlong pathAddress)
{
    char* path = (char*)jlong_to_ptr(pathAddress);
    const char* mime = (*gnome_vfs_mime_type_from_name)(path);

    if (mime == NULL) {
        return NULL;
    } else {
        jbyteArray result;
        jsize len = strlen(mime);
        result = (*env)->NewByteArray(env, len);
        if (result != NULL) {
            (*env)->SetByteArrayRegion(env, result, 0, len, (jbyte*)mime);
        }
        return result;
    }
}