| # Module 'riscospath' -- common operations on RISC OS pathnames. |
| |
| # contributed by Andrew Clover ( andrew@oaktree.co.uk ) |
| |
| # The "os.path" name is an alias for this module on RISC OS systems; |
| # on other systems (e.g. Mac, Windows), os.path provides the same |
| # operations in a manner specific to that platform, and is an alias |
| # to another module (e.g. macpath, ntpath). |
| |
| """ |
| Instead of importing this module directly, import os and refer to this module |
| as os.path. |
| """ |
| |
| |
| # Imports - make an error-generating swi object if the swi module is not |
| # available (ie. we are not running on RISC OS Python) |
| |
| import os, stat, string |
| |
| try: |
| import swi |
| except ImportError: |
| class _swi: |
| def swi(*a): |
| raise AttributeError, 'This function only available under RISC OS' |
| block= swi |
| swi= _swi() |
| |
| [_false, _true]= range(2) |
| |
| _roots= ['$', '&', '%', '@', '\\'] |
| |
| |
| # _allowMOSFSNames |
| # After importing riscospath, set _allowMOSFSNames true if you want the module |
| # to understand the "-SomeFS-" notation left over from the old BBC Master MOS, |
| # as well as the standard "SomeFS:" notation. Set this to be fully backwards |
| # compatible but remember that "-SomeFS-" can also be a perfectly valid file |
| # name so care must be taken when splitting and joining paths. |
| |
| _allowMOSFSNames= _false |
| |
| |
| ## Path manipulation, RISC OS stylee. |
| |
| def _split(p): |
| """ |
| split filing system name (including special field) and drive specifier from rest |
| of path. This is needed by many riscospath functions. |
| """ |
| dash= _allowMOSFSNames and p[:1]=='-' |
| if dash: |
| q= string.find(p, '-', 1)+1 |
| else: |
| if p[:1]==':': |
| q= 0 |
| else: |
| q= string.find(p, ':')+1 # q= index of start of non-FS portion of path |
| s= string.find(p, '#') |
| if s==-1 or s>q: |
| s= q # find end of main FS name, not including special field |
| else: |
| for c in p[dash:s]: |
| if c not in string.ascii_letters: |
| q= 0 |
| break # disallow invalid non-special-field characters in FS name |
| r= q |
| if p[q:q+1]==':': |
| r= string.find(p, '.', q+1)+1 |
| if r==0: |
| r= len(p) # find end of drive name (if any) following FS name (if any) |
| return (p[:q], p[q:r], p[r:]) |
| |
| |
| def normcase(p): |
| """ |
| Normalize the case of a pathname. This converts to lowercase as the native RISC |
| OS filesystems are case-insensitive. However, not all filesystems have to be, |
| and there's no simple way to find out what type an FS is argh. |
| """ |
| return string.lower(p) |
| |
| |
| def isabs(p): |
| """ |
| Return whether a path is absolute. Under RISC OS, a file system specifier does |
| not make a path absolute, but a drive name or number does, and so does using the |
| symbol for root, URD, library, CSD or PSD. This means it is perfectly possible |
| to have an "absolute" URL dependent on the current working directory, and |
| equally you can have a "relative" URL that's on a completely different device to |
| the current one argh. |
| """ |
| (fs, drive, path)= _split(p) |
| return drive!='' or path[:1] in _roots |
| |
| |
| def join(a, *p): |
| """ |
| Join path elements with the directory separator, replacing the entire path when |
| an absolute or FS-changing path part is found. |
| """ |
| j= a |
| for b in p: |
| (fs, drive, path)= _split(b) |
| if j=='' or fs!='' or drive!='' or path[:1] in _roots: |
| j= b |
| elif j[-1]==':': |
| j= j+b |
| else: |
| j= j+'.'+b |
| return j |
| |
| |
| def split(p): |
| """ |
| Split a path in head (everything up to the last '.') and tail (the rest). FS |
| name must still be dealt with separately since special field may contain '.'. |
| """ |
| (fs, drive, path)= _split(p) |
| q= string.rfind(path, '.') |
| if q!=-1: |
| return (fs+drive+path[:q], path[q+1:]) |
| return ('', p) |
| |
| |
| def splitext(p): |
| """ |
| Split a path in root and extension. This assumes the 'using slash for dot and |
| dot for slash with foreign files' convention common in RISC OS is in force. |
| """ |
| (tail, head)= split(p) |
| if '/' in head: |
| q= len(head)-string.rfind(head, '/') |
| return (p[:-q], p[-q:]) |
| return (p, '') |
| |
| |
| def splitdrive(p): |
| """ |
| Split a pathname into a drive specification (including FS name) and the rest of |
| the path. The terminating dot of the drive name is included in the drive |
| specification. |
| """ |
| (fs, drive, path)= _split(p) |
| return (fs+drive, p) |
| |
| |
| def basename(p): |
| """ |
| Return the tail (basename) part of a path. |
| """ |
| return split(p)[1] |
| |
| |
| def dirname(p): |
| """ |
| Return the head (dirname) part of a path. |
| """ |
| return split(p)[0] |
| |
| |
| def commonprefix(ps): |
| """ |
| Return the longest prefix of all list elements. Purely string-based; does not |
| separate any path parts. Why am I in os.path? |
| """ |
| if len(ps)==0: |
| return '' |
| prefix= ps[0] |
| for p in ps[1:]: |
| prefix= prefix[:len(p)] |
| for i in range(len(prefix)): |
| if prefix[i] <> p[i]: |
| prefix= prefix[:i] |
| if i==0: |
| return '' |
| break |
| return prefix |
| |
| |
| ## File access functions. Why are we in os.path? |
| |
| def getsize(p): |
| """ |
| Return the size of a file, reported by os.stat(). |
| """ |
| st= os.stat(p) |
| return st[stat.ST_SIZE] |
| |
| |
| def getmtime(p): |
| """ |
| Return the last modification time of a file, reported by os.stat(). |
| """ |
| st = os.stat(p) |
| return st[stat.ST_MTIME] |
| |
| getatime= getmtime |
| |
| |
| # RISC OS-specific file access functions |
| |
| def exists(p): |
| """ |
| Test whether a path exists. |
| """ |
| try: |
| return swi.swi('OS_File', '5s;i', p)!=0 |
| except swi.error: |
| return 0 |
| |
| |
| def isdir(p): |
| """ |
| Is a path a directory? Includes image files. |
| """ |
| try: |
| return swi.swi('OS_File', '5s;i', p) in [2, 3] |
| except swi.error: |
| return 0 |
| |
| |
| def isfile(p): |
| """ |
| Test whether a path is a file, including image files. |
| """ |
| try: |
| return swi.swi('OS_File', '5s;i', p) in [1, 3] |
| except swi.error: |
| return 0 |
| |
| |
| def islink(p): |
| """ |
| RISC OS has no links or mounts. |
| """ |
| return _false |
| |
| ismount= islink |
| |
| |
| # Same-file testing. |
| |
| # samefile works on filename comparison since there is no ST_DEV and ST_INO is |
| # not reliably unique (esp. directories). First it has to normalise the |
| # pathnames, which it can do 'properly' using OS_FSControl since samefile can |
| # assume it's running on RISC OS (unlike normpath). |
| |
| def samefile(fa, fb): |
| """ |
| Test whether two pathnames reference the same actual file. |
| """ |
| l= 512 |
| b= swi.block(l) |
| swi.swi('OS_FSControl', 'isb..i', 37, fa, b, l) |
| fa= b.ctrlstring() |
| swi.swi('OS_FSControl', 'isb..i', 37, fb, b, l) |
| fb= b.ctrlstring() |
| return fa==fb |
| |
| |
| def sameopenfile(a, b): |
| """ |
| Test whether two open file objects reference the same file. |
| """ |
| return os.fstat(a)[stat.ST_INO]==os.fstat(b)[stat.ST_INO] |
| |
| |
| ## Path canonicalisation |
| |
| # 'user directory' is taken as meaning the User Root Directory, which is in |
| # practice never used, for anything. |
| |
| def expanduser(p): |
| (fs, drive, path)= _split(p) |
| l= 512 |
| b= swi.block(l) |
| |
| if path[:1]!='@': |
| return p |
| if fs=='': |
| fsno= swi.swi('OS_Args', '00;i') |
| swi.swi('OS_FSControl', 'iibi', 33, fsno, b, l) |
| fsname= b.ctrlstring() |
| else: |
| if fs[:1]=='-': |
| fsname= fs[1:-1] |
| else: |
| fsname= fs[:-1] |
| fsname= string.split(fsname, '#', 1)[0] # remove special field from fs |
| x= swi.swi('OS_FSControl', 'ib2s.i;.....i', 54, b, fsname, l) |
| if x<l: |
| urd= b.tostring(0, l-x-1) |
| else: # no URD! try CSD |
| x= swi.swi('OS_FSControl', 'ib0s.i;.....i', 54, b, fsname, l) |
| if x<l: |
| urd= b.tostring(0, l-x-1) |
| else: # no CSD! use root |
| urd= '$' |
| return fsname+':'+urd+path[1:] |
| |
| # Environment variables are in angle brackets. |
| |
| def expandvars(p): |
| """ |
| Expand environment variables using OS_GSTrans. |
| """ |
| l= 512 |
| b= swi.block(l) |
| return b.tostring(0, swi.swi('OS_GSTrans', 'sbi;..i', p, b, l)) |
| |
| |
| # Return an absolute path. |
| |
| def abspath(p): |
| return normpath(join(os.getcwd(), p)) |
| |
| |
| # realpath is a no-op on systems without islink support |
| realpath = abspath |
| |
| |
| # Normalize a path. Only special path element under RISC OS is "^" for "..". |
| |
| def normpath(p): |
| """ |
| Normalize path, eliminating up-directory ^s. |
| """ |
| (fs, drive, path)= _split(p) |
| rhs= '' |
| ups= 0 |
| while path!='': |
| (path, el)= split(path) |
| if el=='^': |
| ups= ups+1 |
| else: |
| if ups>0: |
| ups= ups-1 |
| else: |
| if rhs=='': |
| rhs= el |
| else: |
| rhs= el+'.'+rhs |
| while ups>0: |
| ups= ups-1 |
| rhs= '^.'+rhs |
| return fs+drive+rhs |
| |
| |
| # Directory tree walk. |
| # Independent of host system. Why am I in os.path? |
| |
| def walk(top, func, arg): |
| """Directory tree walk with callback function. |
| |
| For each directory in the directory tree rooted at top (including top |
| itself, but excluding '.' and '..'), call func(arg, dirname, fnames). |
| dirname is the name of the directory, and fnames a list of the names of |
| the files and subdirectories in dirname (excluding '.' and '..'). func |
| may modify the fnames list in-place (e.g. via del or slice assignment), |
| and walk will only recurse into the subdirectories whose names remain in |
| fnames; this can be used to implement a filter, or to impose a specific |
| order of visiting. No semantics are defined for, or required of, arg, |
| beyond that arg is always passed to func. It can be used, e.g., to pass |
| a filename pattern, or a mutable object designed to accumulate |
| statistics. Passing None for arg is common.""" |
| |
| try: |
| names= os.listdir(top) |
| except os.error: |
| return |
| func(arg, top, names) |
| for name in names: |
| name= join(top, name) |
| if isdir(name) and not islink(name): |
| walk(name, func, arg) |