1 # Module 'riscospath' -- common operations on RISC OS pathnames.
3 # contributed by Andrew Clover ( andrew@oaktree.co.uk )
5 # The "os.path" name is an alias for this module on RISC OS systems;
6 # on other systems (e.g. Mac, Windows), os.path provides the same
7 # operations in a manner specific to that platform, and is an alias
8 # to another module (e.g. macpath, ntpath).
11 Instead of importing this module directly, import os and refer to this module
15 # strings representing various path-related bits and pieces
24 # Imports - make an error-generating swi object if the swi module is not
25 # available (ie. we are not running on RISC OS Python)
27 import os
, stat
, string
34 raise AttributeError, 'This function only available under RISC OS'
38 [_false
, _true
]= range(2)
40 _roots
= ['$', '&', '%', '@', '\\']
44 # After importing riscospath, set _allowMOSFSNames true if you want the module
45 # to understand the "-SomeFS-" notation left over from the old BBC Master MOS,
46 # as well as the standard "SomeFS:" notation. Set this to be fully backwards
47 # compatible but remember that "-SomeFS-" can also be a perfectly valid file
48 # name so care must be taken when splitting and joining paths.
50 _allowMOSFSNames
= _false
53 ## Path manipulation, RISC OS stylee.
57 split filing system name (including special field) and drive specifier from rest
58 of path. This is needed by many riscospath functions.
60 dash
= _allowMOSFSNames
and p
[:1]=='-'
62 q
= string
.find(p
, '-', 1)+1
67 q
= string
.find(p
, ':')+1 # q= index of start of non-FS portion of path
68 s
= string
.find(p
, '#')
70 s
= q
# find end of main FS name, not including special field
73 if c
not in string
.ascii_letters
:
75 break # disallow invalid non-special-field characters in FS name
78 r
= string
.find(p
, '.', q
+1)+1
80 r
= len(p
) # find end of drive name (if any) following FS name (if any)
81 return (p
[:q
], p
[q
:r
], p
[r
:])
86 Normalize the case of a pathname. This converts to lowercase as the native RISC
87 OS filesystems are case-insensitive. However, not all filesystems have to be,
88 and there's no simple way to find out what type an FS is argh.
90 return string
.lower(p
)
95 Return whether a path is absolute. Under RISC OS, a file system specifier does
96 not make a path absolute, but a drive name or number does, and so does using the
97 symbol for root, URD, library, CSD or PSD. This means it is perfectly possible
98 to have an "absolute" URL dependent on the current working directory, and
99 equally you can have a "relative" URL that's on a completely different device to
100 the current one argh.
102 (fs
, drive
, path
)= _split(p
)
103 return drive
!='' or path
[:1] in _roots
108 Join path elements with the directory separator, replacing the entire path when
109 an absolute or FS-changing path part is found.
113 (fs
, drive
, path
)= _split(b
)
114 if j
=='' or fs
!='' or drive
!='' or path
[:1] in _roots
:
125 Split a path in head (everything up to the last '.') and tail (the rest). FS
126 name must still be dealt with separately since special field may contain '.'.
128 (fs
, drive
, path
)= _split(p
)
129 q
= string
.rfind(path
, '.')
131 return (fs
+drive
+path
[:q
], path
[q
+1:])
137 Split a path in root and extension. This assumes the 'using slash for dot and
138 dot for slash with foreign files' convention common in RISC OS is in force.
140 (tail
, head
)= split(p
)
142 q
= len(head
)-string
.rfind(head
, '/')
143 return (p
[:-q
], p
[-q
:])
149 Split a pathname into a drive specification (including FS name) and the rest of
150 the path. The terminating dot of the drive name is included in the drive
153 (fs
, drive
, path
)= _split(p
)
159 Return the tail (basename) part of a path.
166 Return the head (dirname) part of a path.
172 "Given a list of pathnames, returns the longest common leading component"
176 n
= min(len(s1
), len(s2
))
183 ## File access functions. Why are we in os.path?
187 Return the size of a file, reported by os.stat().
190 return st
[stat
.ST_SIZE
]
195 Return the last modification time of a file, reported by os.stat().
198 return st
[stat
.ST_MTIME
]
203 # RISC OS-specific file access functions
207 Test whether a path exists.
210 return swi
.swi('OS_File', '5s;i', p
)!=0
219 Is a path a directory? Includes image files.
222 return swi
.swi('OS_File', '5s;i', p
) in [2, 3]
229 Test whether a path is a file, including image files.
232 return swi
.swi('OS_File', '5s;i', p
) in [1, 3]
239 RISC OS has no links or mounts.
248 # samefile works on filename comparison since there is no ST_DEV and ST_INO is
249 # not reliably unique (esp. directories). First it has to normalise the
250 # pathnames, which it can do 'properly' using OS_FSControl since samefile can
251 # assume it's running on RISC OS (unlike normpath).
253 def samefile(fa
, fb
):
255 Test whether two pathnames reference the same actual file.
259 swi
.swi('OS_FSControl', 'isb..i', 37, fa
, b
, l
)
261 swi
.swi('OS_FSControl', 'isb..i', 37, fb
, b
, l
)
266 def sameopenfile(a
, b
):
268 Test whether two open file objects reference the same file.
270 return os
.fstat(a
)[stat
.ST_INO
]==os
.fstat(b
)[stat
.ST_INO
]
273 ## Path canonicalisation
275 # 'user directory' is taken as meaning the User Root Directory, which is in
276 # practice never used, for anything.
279 (fs
, drive
, path
)= _split(p
)
286 fsno
= swi
.swi('OS_Args', '00;i')
287 swi
.swi('OS_FSControl', 'iibi', 33, fsno
, b
, l
)
288 fsname
= b
.ctrlstring()
294 fsname
= string
.split(fsname
, '#', 1)[0] # remove special field from fs
295 x
= swi
.swi('OS_FSControl', 'ib2s.i;.....i', 54, b
, fsname
, l
)
297 urd
= b
.tostring(0, l
-x
-1)
298 else: # no URD! try CSD
299 x
= swi
.swi('OS_FSControl', 'ib0s.i;.....i', 54, b
, fsname
, l
)
301 urd
= b
.tostring(0, l
-x
-1)
302 else: # no CSD! use root
304 return fsname
+':'+urd
+path
[1:]
306 # Environment variables are in angle brackets.
310 Expand environment variables using OS_GSTrans.
314 return b
.tostring(0, swi
.swi('OS_GSTrans', 'sbi;..i', p
, b
, l
))
317 # Return an absolute path. RISC OS' osfscontrol_canonicalise_path does this among others
321 # realpath is a no-op on systems without islink support
325 # Normalize a path. Only special path element under RISC OS is "^" for "..".
329 Normalize path, eliminating up-directory ^s.
331 (fs
, drive
, path
)= _split(p
)
335 (path
, el
)= split(path
)
352 # Directory tree walk.
353 # Independent of host system. Why am I in os.path?
355 def walk(top
, func
, arg
):
356 """Directory tree walk with callback function.
358 For each directory in the directory tree rooted at top (including top
359 itself, but excluding '.' and '..'), call func(arg, dirname, fnames).
360 dirname is the name of the directory, and fnames a list of the names of
361 the files and subdirectories in dirname (excluding '.' and '..'). func
362 may modify the fnames list in-place (e.g. via del or slice assignment),
363 and walk will only recurse into the subdirectories whose names remain in
364 fnames; this can be used to implement a filter, or to impose a specific
365 order of visiting. No semantics are defined for, or required of, arg,
366 beyond that arg is always passed to func. It can be used, e.g., to pass
367 a filename pattern, or a mutable object designed to accumulate
368 statistics. Passing None for arg is common."""
371 names
= os
.listdir(top
)
374 func(arg
, top
, names
)
376 name
= join(top
, name
)
377 if isdir(name
) and not islink(name
):
378 walk(name
, func
, arg
)