Guido van Rossum | 228d807 | 2001-03-02 05:58:11 +0000 | [diff] [blame] | 1 | # Module 'riscospath' -- common operations on RISC OS pathnames. |
| 2 | |
| 3 | # contributed by Andrew Clover ( andrew@oaktree.co.uk ) |
| 4 | |
| 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). |
| 9 | |
| 10 | """ |
| 11 | Instead of importing this module directly, import os and refer to this module |
| 12 | as os.path. |
| 13 | """ |
| 14 | |
| 15 | |
| 16 | # Imports - make an error-generating swi object if the swi module is not |
| 17 | # available (ie. we are not running on RISC OS Python) |
| 18 | |
| 19 | import os, stat, string |
| 20 | |
| 21 | try: |
| 22 | import swi |
| 23 | except ImportError: |
| 24 | class _swi: |
| 25 | def swi(*a): |
| 26 | raise AttributeError, 'This function only available under RISC OS' |
| 27 | block= swi |
| 28 | swi= _swi() |
| 29 | |
| 30 | [_false, _true]= range(2) |
| 31 | |
| 32 | _roots= ['$', '&', '%', '@', '\\'] |
| 33 | |
| 34 | |
| 35 | # _allowMOSFSNames |
| 36 | # After importing riscospath, set _allowMOSFSNames true if you want the module |
| 37 | # to understand the "-SomeFS-" notation left over from the old BBC Master MOS, |
| 38 | # as well as the standard "SomeFS:" notation. Set this to be fully backwards |
| 39 | # compatible but remember that "-SomeFS-" can also be a perfectly valid file |
| 40 | # name so care must be taken when splitting and joining paths. |
| 41 | |
| 42 | _allowMOSFSNames= _false |
| 43 | |
| 44 | |
| 45 | ## Path manipulation, RISC OS stylee. |
| 46 | |
| 47 | def _split(p): |
| 48 | """ |
| 49 | split filing system name (including special field) and drive specifier from rest |
| 50 | of path. This is needed by many riscospath functions. |
| 51 | """ |
| 52 | dash= _allowMOSFSNames and p[:1]=='-' |
| 53 | if dash: |
| 54 | q= string.find(p, '-', 1)+1 |
| 55 | else: |
| 56 | if p[:1]==':': |
| 57 | q= 0 |
| 58 | else: |
| 59 | q= string.find(p, ':')+1 # q= index of start of non-FS portion of path |
| 60 | s= string.find(p, '#') |
| 61 | if s==-1 or s>q: |
| 62 | s= q # find end of main FS name, not including special field |
| 63 | else: |
| 64 | for c in p[dash:s]: |
| 65 | if c not in string.letters: |
| 66 | q= 0 |
| 67 | break # disallow invalid non-special-field characters in FS name |
| 68 | r= q |
| 69 | if p[q:q+1]==':': |
| 70 | r= string.find(p, '.', q+1)+1 |
| 71 | if r==0: |
| 72 | r= len(p) # find end of drive name (if any) following FS name (if any) |
| 73 | return (p[:q], p[q:r], p[r:]) |
| 74 | |
| 75 | |
| 76 | def normcase(p): |
| 77 | """ |
| 78 | Normalize the case of a pathname. This converts to lowercase as the native RISC |
| 79 | OS filesystems are case-insensitive. However, not all filesystems have to be, |
| 80 | and there's no simple way to find out what type an FS is argh. |
| 81 | """ |
| 82 | return string.lower(p) |
| 83 | |
| 84 | |
| 85 | def isabs(p): |
| 86 | """ |
| 87 | Return whether a path is absolute. Under RISC OS, a file system specifier does |
| 88 | not make a path absolute, but a drive name or number does, and so does using the |
| 89 | symbol for root, URD, library, CSD or PSD. This means it is perfectly possible |
| 90 | to have an "absolute" URL dependent on the current working directory, and |
| 91 | equally you can have a "relative" URL that's on a completely different device to |
| 92 | the current one argh. |
| 93 | """ |
| 94 | (fs, drive, path)= _split(p) |
| 95 | return drive!='' or path[:1] in _roots |
| 96 | |
| 97 | |
| 98 | def join(a, *p): |
| 99 | """ |
| 100 | Join path elements with the directory separator, replacing the entire path when |
| 101 | an absolute or FS-changing path part is found. |
| 102 | """ |
| 103 | j= a |
| 104 | for b in p: |
| 105 | (fs, drive, path)= _split(b) |
| 106 | if fs!='' or drive!='' or path[:1] in _roots: |
| 107 | j= b |
| 108 | else: |
| 109 | j= j+'.'+b |
| 110 | return j |
| 111 | |
| 112 | |
| 113 | def split(p): |
| 114 | """ |
| 115 | Split a path in head (everything up to the last '.') and tail (the rest). FS |
| 116 | name must still be dealt with separately since special field may contain '.'. |
| 117 | """ |
| 118 | (fs, drive, path)= _split(p) |
| 119 | q= string.rfind(path, '.') |
| 120 | if q!=-1: |
| 121 | return (fs+drive+path[:q], path[q+1:]) |
| 122 | return ('', p) |
| 123 | |
| 124 | |
| 125 | def splitext(p): |
| 126 | """ |
| 127 | Split a path in root and extension. This assumes the 'using slash for dot and |
| 128 | dot for slash with foreign files' convention common in RISC OS is in force. |
| 129 | """ |
| 130 | (tail, head)= split(p) |
| 131 | if '/' in head: |
| 132 | q= len(head)-string.rfind(head, '/') |
| 133 | return (p[:-q], p[-q:]) |
| 134 | return (p, '') |
| 135 | |
| 136 | |
| 137 | def splitdrive(p): |
| 138 | """ |
| 139 | Split a pathname into a drive specification (including FS name) and the rest of |
| 140 | the path. The terminating dot of the drive name is included in the drive |
| 141 | specification. |
| 142 | """ |
| 143 | (fs, drive, path)= _split(p) |
| 144 | return (fs+drive, p) |
| 145 | |
| 146 | |
| 147 | def basename(p): |
| 148 | """ |
| 149 | Return the tail (basename) part of a path. |
| 150 | """ |
| 151 | return split(p)[1] |
| 152 | |
| 153 | |
| 154 | def dirname(p): |
| 155 | """ |
| 156 | Return the head (dirname) part of a path. |
| 157 | """ |
| 158 | return split(p)[0] |
| 159 | |
| 160 | |
| 161 | def commonprefix(ps): |
| 162 | """ |
| 163 | Return the longest prefix of all list elements. Purely string-based; does not |
| 164 | separate any path parts. Why am I in os.path? |
| 165 | """ |
| 166 | if len(ps)==0: |
| 167 | return '' |
| 168 | prefix= ps[0] |
| 169 | for p in ps[1:]: |
| 170 | prefix= prefix[:len(p)] |
| 171 | for i in range(len(prefix)): |
| 172 | if prefix[i] <> p[i]: |
| 173 | prefix= prefix[:i] |
| 174 | if i==0: |
| 175 | return '' |
| 176 | break |
| 177 | return prefix |
| 178 | |
| 179 | |
| 180 | ## File access functions. Why are we in os.path? |
| 181 | |
| 182 | def getsize(p): |
| 183 | """ |
| 184 | Return the size of a file, reported by os.stat(). |
| 185 | """ |
| 186 | st= os.stat(p) |
| 187 | return st[stat.ST_SIZE] |
| 188 | |
| 189 | |
| 190 | def getmtime(p): |
| 191 | """ |
| 192 | Return the last modification time of a file, reported by os.stat(). |
| 193 | """ |
| 194 | st = os.stat(p) |
| 195 | return st[stat.ST_MTIME] |
| 196 | |
| 197 | getatime= getmtime |
| 198 | |
| 199 | |
| 200 | # RISC OS-specific file access functions |
| 201 | |
| 202 | def exists(p): |
| 203 | """ |
| 204 | Test whether a path exists. |
| 205 | """ |
Guido van Rossum | bceccf5 | 2001-04-10 22:07:43 +0000 | [diff] [blame] | 206 | try: |
| 207 | return swi.swi('OS_File', '5s;i', p)!=0 |
| 208 | except swi.error: |
| 209 | return 0 |
Guido van Rossum | 228d807 | 2001-03-02 05:58:11 +0000 | [diff] [blame] | 210 | |
| 211 | |
| 212 | def isdir(p): |
| 213 | """ |
| 214 | Is a path a directory? Includes image files. |
| 215 | """ |
Guido van Rossum | bceccf5 | 2001-04-10 22:07:43 +0000 | [diff] [blame] | 216 | try: |
| 217 | return swi.swi('OS_File', '5s;i', p) in [2, 3] |
| 218 | except swi.error: |
| 219 | return 0 |
Guido van Rossum | 228d807 | 2001-03-02 05:58:11 +0000 | [diff] [blame] | 220 | |
| 221 | |
| 222 | def isfile(p): |
| 223 | """ |
| 224 | Test whether a path is a file, including image files. |
| 225 | """ |
Guido van Rossum | bceccf5 | 2001-04-10 22:07:43 +0000 | [diff] [blame] | 226 | try: |
| 227 | return swi.swi('OS_File', '5s;i', p) in [1, 3] |
| 228 | except swi.error: |
| 229 | return 0 |
Guido van Rossum | 228d807 | 2001-03-02 05:58:11 +0000 | [diff] [blame] | 230 | |
| 231 | |
| 232 | def islink(p): |
| 233 | """ |
| 234 | RISC OS has no links or mounts. |
| 235 | """ |
| 236 | return _false |
| 237 | |
| 238 | ismount= islink |
| 239 | |
| 240 | |
| 241 | # Same-file testing. |
| 242 | |
| 243 | # samefile works on filename comparison since there is no ST_DEV and ST_INO is |
| 244 | # not reliably unique (esp. directories). First it has to normalise the |
| 245 | # pathnames, which it can do 'properly' using OS_FSControl since samefile can |
| 246 | # assume it's running on RISC OS (unlike normpath). |
| 247 | |
| 248 | def samefile(fa, fb): |
| 249 | """ |
| 250 | Test whether two pathnames reference the same actual file. |
| 251 | """ |
| 252 | l= 512 |
| 253 | b= swi.block(l) |
| 254 | swi.swi('OS_FSControl', 'isb..i', 37, fa, b, l) |
| 255 | fa= b.ctrlstring() |
| 256 | swi.swi('OS_FSControl', 'isb..i', 37, fb, b, l) |
| 257 | fb= b.ctrlstring() |
| 258 | return fa==fb |
| 259 | |
| 260 | |
| 261 | def sameopenfile(a, b): |
| 262 | """ |
| 263 | Test whether two open file objects reference the same file. |
| 264 | """ |
| 265 | return os.fstat(a)[stat.ST_INO]==os.fstat(b)[stat.ST_INO] |
| 266 | |
| 267 | |
| 268 | ## Path canonicalisation |
| 269 | |
| 270 | # 'user directory' is taken as meaning the User Root Directory, which is in |
| 271 | # practice never used, for anything. |
| 272 | |
| 273 | def expanduser(p): |
| 274 | (fs, drive, path)= _split(p) |
| 275 | l= 512 |
| 276 | b= swi.block(l) |
| 277 | |
| 278 | if path[:1]!='@': |
| 279 | return p |
| 280 | if fs=='': |
| 281 | fsno= swi.swi('OS_Args', '00;i') |
| 282 | swi.swi('OS_FSControl', 'iibi', 33, fsno, b, l) |
| 283 | fsname= b.ctrlstring() |
| 284 | else: |
| 285 | if fs[:1]=='-': |
| 286 | fsname= fs[1:-1] |
| 287 | else: |
| 288 | fsname= fs[:-1] |
| 289 | fsname= string.split(fsname, '#', 1)[0] # remove special field from fs |
| 290 | x= swi.swi('OS_FSControl', 'ib2s.i;.....i', 54, b, fsname, l) |
| 291 | if x<l: |
| 292 | urd= b.tostring(0, l-x-1) |
| 293 | else: # no URD! try CSD |
| 294 | x= swi.swi('OS_FSControl', 'ib0s.i;.....i', 54, b, fsname, l) |
| 295 | if x<l: |
| 296 | urd= b.tostring(0, l-x-1) |
| 297 | else: # no CSD! use root |
| 298 | urd= '$' |
| 299 | return fsname+':'+urd+path[1:] |
| 300 | |
| 301 | # Environment variables are in angle brackets. |
| 302 | |
| 303 | def expandvars(p): |
| 304 | """ |
| 305 | Expand environment variables using OS_GSTrans. |
| 306 | """ |
| 307 | l= 512 |
| 308 | b= swi.block(l) |
| 309 | return b.tostring(0, swi.swi('OS_GSTrans', 'sbi;..i', p, b, l)) |
| 310 | |
| 311 | |
| 312 | # Return an absolute path. |
| 313 | |
| 314 | def abspath(p): |
| 315 | return normpath(join(os.getcwd(), p)) |
| 316 | |
| 317 | |
| 318 | # Normalize a path. Only special path element under RISC OS is "^" for "..". |
| 319 | |
| 320 | def normpath(p): |
| 321 | """ |
| 322 | Normalize path, eliminating up-directory ^s. |
| 323 | """ |
| 324 | (fs, drive, path)= _split(p) |
| 325 | rhs= '' |
| 326 | ups= 0 |
| 327 | while path!='': |
| 328 | (path, el)= split(path) |
| 329 | if el=='^': |
| 330 | ups= ups+1 |
| 331 | else: |
| 332 | if ups>0: |
| 333 | ups= ups-1 |
| 334 | else: |
| 335 | if rhs=='': |
| 336 | rhs= el |
| 337 | else: |
| 338 | rhs= el+'.'+rhs |
| 339 | while ups>0: |
| 340 | ups= ups-1 |
| 341 | rhs= '^.'+rhs |
| 342 | return fs+drive+rhs |
| 343 | |
| 344 | |
| 345 | # Directory tree walk. |
| 346 | # Independent of host system. Why am I in os.path? |
| 347 | |
| 348 | def walk(top, func, arg): |
| 349 | """ |
| 350 | walk(top,func,args) calls func(arg, d, files) for each directory "d" in the tree |
| 351 | rooted at "top" (including "top" itself). "files" is a list of all the files and |
| 352 | subdirs in directory "d". |
| 353 | """ |
| 354 | try: |
| 355 | names= os.listdir(top) |
| 356 | except os.error: |
| 357 | return |
| 358 | func(arg, top, names) |
| 359 | for name in names: |
| 360 | name= join(top, name) |
| 361 | if isdir(name) and not islink(name): |
| 362 | walk(name, func, arg) |
| 363 | |