1	//go:build linux
     2	
     3	/*
     4	Copyright 2012 The Perkeep Authors
     5	
     6	Licensed under the Apache License, Version 2.0 (the "License");
     7	you may not use this file except in compliance with the License.
     8	You may obtain a copy of the License at
     9	
    10	     http://www.apache.org/licenses/LICENSE-2.0
    11	
    12	Unless required by applicable law or agreed to in writing, software
    13	distributed under the License is distributed on an "AS IS" BASIS,
    14	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15	See the License for the specific language governing permissions and
    16	limitations under the License.
    17	*/
    18	
    19	package fs
    20	
    21	import (
    22		"context"
    23		"os"
    24	
    25		"bazil.org/fuse"
    26		fusefs "bazil.org/fuse/fs"
    27	)
    28	
    29	type atDir struct {
    30		fs *CamliFileSystem
    31	}
    32	
    33	var (
    34		_ fusefs.Node               = (*atDir)(nil)
    35		_ fusefs.HandleReadDirAller = (*atDir)(nil)
    36		_ fusefs.NodeStringLookuper = (*atDir)(nil)
    37	)
    38	
    39	func (n *atDir) Attr(ctx context.Context, a *fuse.Attr) error {
    40		a.Mode = os.ModeDir | 0500
    41		a.Uid = uint32(os.Getuid())
    42		a.Gid = uint32(os.Getgid())
    43		return nil
    44	}
    45	
    46	func (n *atDir) ReadDirAll(ctx context.Context) ([]fuse.Dirent, error) {
    47		return []fuse.Dirent{
    48			{Name: "README.txt"},
    49		}, nil
    50	}
    51	
    52	const atReadme = `You are now in the "at" filesystem, where you can look into the past.
    53	
    54	Locations in the top-level of this directory are dynamically created
    55	as you request them.  A dynamic directory is designated by a
    56	timestamp.  Once you enter a directory, you'll have a read-only view
    57	of all of the roots that existed as of the specified time.
    58	
    59	Example:
    60	
    61	If you had a root called "importantstuff" and a file in it called
    62	"todo.txt", you can look at the contents of that file as it existed
    63	back before Christmas like this (from the location you mounted
    64	camlistore):
    65	
    66	    cat at/2013-12-24/importantstuff/todo.txt
    67	
    68	If you cd into "at/2013-12-24/importantstuff" you can also see all the
    69	files that you deleted since (but none that were created after).
    70	
    71	Timestamps are specified in UTC unless otherwise specified, and may be
    72	in any of the following forms:
    73	
    74	With Nanosecond Granularity
    75	
    76	* 2012-08-28T21:24:35.37465188Z - RFC3339 (this is the canonical format)
    77	* 1346189075374651880 - nanoseconds since 1970-1-1
    78	
    79	With Millisecond Granularity
    80	
    81	* 1346189075374 - milliseconds since 1970-1-1, common in java
    82	
    83	With Second Granularity
    84	
    85	* 1346189075 - seconds since 1970-1-1, common in unix
    86	* 2012-08-28T21:24:35Z - RFC3339
    87	* 2012-08-28T21:24:35-08:00 - RFC3339 with numeric timezone
    88	* Tue, 28 Aug 2012 21:24:35 +0000 - RFC1123 + numeric timezone
    89	* Tue, 28 Aug 2012 21:24:35 UTC - RFC1123
    90	* Tue Aug 28 21:24:35 UTC 2012 - Unix date
    91	* Tue Aug 28 21:24:35 2012 - ansi C timestamp
    92	* Tue Aug 28 21:24:35 +0000 2012 - ruby datestamp
    93	
    94	With More Coarse Granularities
    95	
    96	* 2012-08-28T21:24 (This will be considered the same as 2012-08-28T21:24:00Z)
    97	* 2012-08-28T21    (This will be considered the same as 2012-08-28T21:00:00Z)
    98	* 2012-08-28       (This will be considered the same as 2012-08-28T00:00:00Z)
    99	* 2012-08          (This will be considered the same as 2012-08-01T00:00:00Z)
   100	* 2012             (This will be considered the same as 2012-01-01T00:00:00Z)
   101	`
   102	
   103	func (n *atDir) Lookup(ctx context.Context, name string) (fusefs.Node, error) {
   104		Logger.Printf("fs.atDir: Lookup(%q)", name)
   105	
   106		if name == "README.txt" {
   107			return staticFileNode(atReadme), nil
   108		}
   109	
   110		asOf, err := parseTime(name)
   111		if err != nil {
   112			Logger.Printf("Can't parse time: %v", err)
   113			return nil, fuse.ENOENT
   114		}
   115	
   116		return &rootsDir{fs: n.fs, at: asOf}, nil
   117	}