c gtk+：将文本文件加载到 GtkSourceView 的 TextBuffer 中
我正在使用 C 语言与 gtk+ 和 gtksourceview-2.0 编写一个程序。
我使用 GtkFileChooser 供用户选择一个文件，当他单击它时，我希望将内容加载到 GtkSourceView 的 TextBuffer 中，
这是当用户双击 GtkFileChooser 上的文件时执行的函数：
void on_file_activated(GtkWidget *widget, gpointer data) {
GFile *file;
FILE *fp;
gchar *path_name;
long file_size;
gchararray file_buffer;
file = gtk_file_chooser_get_file(GTK_FILE_CHOOSER(widget));
path_name=g_file_get_path(file);
g_debug("%s is chosen\n", path_name);
fp=fopen(path_name, "r");
g_assert( fp != NULL);
fseek(fp, 0L, SEEK_END);
file_size = ftell(fp);
rewind(fp);
g_debug("file size: %ld\n",file_size*sizeof(gchar));
file_buffer=calloc(file_size, sizeof(gchar));
g_assert(file_buffer != NULL);
fread(&file_buffer,file_size,1,fp);
g_debug("after fread");
//file_buffer[file_size*sizeof(gchar)]=0;
//g_debug("after adding zero: %s",file_buffer);
gtk_text_buffer_set_text (textbuffer, file_buffer,2);
g_debug("after set text");
g_object_unref(file);
}
这是我的应用程序的输出：
** (tour_de_gtk:18107): DEBUG: /home/ufk/Projects/gtk-projects/tour-de-gtk/Debug/src/examples/example_gtk_label/main.c is chosen
** (tour_de_gtk:18107): DEBUG: file size: 16
** (tour_de_gtk:18107): DEBUG: after fread
之后我在命令 gtk_text_buffer_set_text 上出现分段错误，
如您所见，我有两个命令被注释掉。尝试 g_debug 缓冲区，这显然会产生分段错误，因为我没有在字符串末尾添加零，甚至当我尝试在字符串末尾添加零时，我也会遇到分段错误。我可能做错了什么。
在这里，我试图只写入缓冲区的前两个字符，但没有成功。
有什么想法吗？
更新
完成的功能：
void on_file_activated(GtkWidget *widget, gpointer data) {
GFile *file;
gchar *path_name;
long file_size;
gchar *file_buffer;
GError *error;
gboolean read_file_status;
file = gtk_file_chooser_get_file(GTK_FILE_CHOOSER(widget));
path_name=g_file_get_path(file);
g_debug("%s is chosen\n", path_name);
read_file_status=g_file_get_contents (path_name,&file_buffer,NULL, &error);
if (read_file_status == FALSE) {
g_error("error opening file: %s\n",error && error->message ? error->message : "No Detail");
return;
}
gtk_text_buffer_set_text (textbuffer, file_buffer,-1);
g_debug("after set text");
g_object_unref(file);
}
I'm writing a program using the C language with gtk+ and gtksourceview-2.0.
I'm using a GtkFileChooser for the user to choose a file and when he clicks on it, i want the content to be loaded to the GtkSourceView' TextBuffer
this is the function that gets executed when a user double click's a file on the GtkFileChooser:
void on_file_activated(GtkWidget *widget, gpointer data) {
GFile *file;
FILE *fp;
gchar *path_name;
long file_size;
gchararray file_buffer;
file = gtk_file_chooser_get_file(GTK_FILE_CHOOSER(widget));
path_name=g_file_get_path(file);
g_debug("%s is chosen\n", path_name);
fp=fopen(path_name, "r");
g_assert( fp != NULL);
fseek(fp, 0L, SEEK_END);
file_size = ftell(fp);
rewind(fp);
g_debug("file size: %ld\n",file_size*sizeof(gchar));
file_buffer=calloc(file_size, sizeof(gchar));
g_assert(file_buffer != NULL);
fread(&file_buffer,file_size,1,fp);
g_debug("after fread");
//file_buffer[file_size*sizeof(gchar)]=0;
//g_debug("after adding zero: %s",file_buffer);
gtk_text_buffer_set_text (textbuffer, file_buffer,2);
g_debug("after set text");
g_object_unref(file);
}
this is the output of my application:
** (tour_de_gtk:18107): DEBUG: /home/ufk/Projects/gtk-projects/tour-de-gtk/Debug/src/examples/example_gtk_label/main.c is chosen
** (tour_de_gtk:18107): DEBUG: file size: 16
** (tour_de_gtk:18107): DEBUG: after fread
after then i get a segmentation fault on the command gtk_text_buffer_set_text
as you can see i have two commands that are commented out. trying to g_debug the buffer which obviously creates a segmentation fault because i didn't add a zero to the end of the string, and even when I try to add zero to the end of the string i get a segmentation fault. I probably did something wrong.
here i'm trying to write only the first two characters of the buffer but with no luck.
any ideas?
update
the finished function:
void on_file_activated(GtkWidget *widget, gpointer data) {
GFile *file;
gchar *path_name;
long file_size;
gchar *file_buffer;
GError *error;
gboolean read_file_status;
file = gtk_file_chooser_get_file(GTK_FILE_CHOOSER(widget));
path_name=g_file_get_path(file);
g_debug("%s is chosen\n", path_name);
read_file_status=g_file_get_contents (path_name,&file_buffer,NULL, &error);
if (read_file_status == FALSE) {
g_error("error opening file: %s\n",error && error->message ? error->message : "No Detail");
return;
}
gtk_text_buffer_set_text (textbuffer, file_buffer,-1);
g_debug("after set text");
g_object_unref(file);
}
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这里有很多可能的改进，您可能已经知道很多并且只是在乱搞，但我将列出几个以防万一。
只需使用 char*
应该使用断言来处理编程错误，而不是运行时错误，所以这里 g_printerr() 或对话框会更好
fstat(fileno(fp), &statbuf) 可能是更好的方法，但整个方法有点糟糕；与其获取大小，不如直接读入动态增长的缓冲区。或者，如果您愿意预分配整个缓冲区，只需使用 g_file_get_contents()。另一种方法是 g_file_query_info() （它更便携并且使用 vfs）
g_new0(char, file_size) 更好，或者 g_malloc0(file_size)。此外，您还需要 file_size+1 为 nul 字节腾出空间。
这里你需要 file_buffer (a char*) 而不是 &file_buffer (a char**)。这可能是立即破损的真正原因。
您还需要检查 fread() 的返回值。
这里还缺少读入数据的 g_utf8_validate()。
查看 g_file_get_contents() 的实现以了解此处的一种方法。您还可以使用 g_file_load_contents 来使用 GFile 而不是路径（可移植，使用 vfs），或者在现实应用程序中更好的是 g_file_load_contents_async()。
要调试段错误，两个最好的工具是：
There are a lot of improvements possible here, you may already know many and just be messing around, but I'll list several in case.
Just use char*
Should use assert for programming errors, not runtime errors, so here g_printerr() or a dialog would be better
fstat(fileno(fp), &statbuf) is probably a better way to do this, but the whole approach is kind of bad; rather than get the size, it's better to just read into a dynamically-growing buffer. Or if you're willing to preallocate the whole buffer, just use g_file_get_contents(). Another approach is g_file_query_info() (which is more portable and uses the vfs)
g_new0(char, file_size) is nicer, or g_malloc0(file_size). Also you need file_size+1 to make room for the nul byte.
Here you want file_buffer (a char*) rather than &file_buffer (a char**). This is probably the actual cause of the immediate breakage.
You also need to check the return value of fread().
Also missing here is g_utf8_validate() on the data read in.
Have a look at the implementation of g_file_get_contents() to see one approach here. You could also use g_file_load_contents to use a GFile instead of a path (portable, uses vfs) or better yet in a real-world app, g_file_load_contents_async().
To debug segfaults, the two best tools are: