public async Task <Message> GetAsync(bool remove_items,
CancellationToken token = default)
{
using (var releaser = await _databaseLimit.EnterAsync())
{
using (var context = new QueueContext(_databaseFileName))
{
List <QueueItem> items = new List <QueueItem>();
var first = context.Items.OrderBy(o => o.ID).FirstOrDefault();
if (first == null)
{
return(null);
}
items.Add(first);
if (string.IsNullOrEmpty(first.GroupID))
{
return new Message {
Content = first.Content
}
}
;
// 取出所有 GroupID 相同的事项，然后拼接起来
var group_id = first.GroupID;
List <byte> bytes = new List <byte>(first.Content);
int id = first.ID;
while (true)
{
var current = context.Items.Where(o => o.ID > id).OrderBy(o => o.ID).FirstOrDefault();
if (current == null)
{
break;
}
if (current.GroupID != group_id)
{
break;
}
bytes.AddRange(current.Content);
id = current.ID;
items.Add(current);
}
// 删除涉及到的事项
if (remove_items)
{
context.Items.RemoveRange(items);
await context.SaveChangesAsync(token);
}
return(new Message {
Content = bytes.ToArray()
});
}
}
}
public async Task PushAsync(List <string> texts,
CancellationToken token = default)
{
using (var releaser = await _databaseLimit.EnterAsync())
{
using (var context = new QueueContext(_databaseFileName))
{
foreach (string text in texts)
{
context.Items.AddRange(BuildItem(text));
}
await context.SaveChangesAsync(token).ConfigureAwait(false);
}
}
}
public async Task PushAsync(List <byte[]> contents,
CancellationToken token = default)
{
using (var releaser = await _databaseLimit.EnterAsync())
{
using (var context = new QueueContext(_databaseFileName))
{
foreach (var content in contents)
{
// 注意，这里每次 Add() 以后都要及时 SaveChanges()。否则 ID 的顺序会发生混乱
var items = BuildItem(content);
foreach (var item in items)
{
context.Items.Add(item);
await context.SaveChangesAsync(token);
}
}
}
}
}