rename markupbase to _markupbase

author: Fred Drake <fdrake@acm.org> 2007-12-07 11:10:11 +0000
committer: Fred Drake <fdrake@acm.org> 2007-12-07 11:10:11 +0000
commit: 06d56a591b365a066955988de856b0ee947ae226 (patch)
tree: c5db3f9573569fcc04b2f8d314078981d7491a06 /Lib/_markupbase.py
parent: 716ad6b335fbdf5ba53dbdc3a17bd835fed19241 (diff)
download: cpython-06d56a591b365a066955988de856b0ee947ae226.tar.gz
1 files changed, 392 insertions, 0 deletions
diff --git a/Lib/_markupbase.py b/Lib/_markupbase.py
new file mode 100644
index 0000000000..b178470944
--- /dev/null
+++ b/Lib/_markupbase.py
@@ -0,0 +1,392 @@
+"""Shared support for scanning document type declarations in HTML and XHTML.
+
+This module is used as a foundation for the HTMLParser and sgmllib
+modules (indirectly, for htmllib as well).  It has no documented
+public API and should not be used directly.
+
+"""
+
+import re
+
+_declname_match = re.compile(r'[a-zA-Z][-_.a-zA-Z0-9]*\s*').match
+_declstringlit_match = re.compile(r'(\'[^\']*\'|"[^"]*")\s*').match
+_commentclose = re.compile(r'--\s*>')
+_markedsectionclose = re.compile(r']\s*]\s*>')
+
+# An analysis of the MS-Word extensions is available at
+# http://www.planetpublish.com/xmlarena/xap/Thursday/WordtoXML.pdf
+
+_msmarkedsectionclose = re.compile(r']\s*>')
+
+del re
+
+
+class ParserBase:
+    """Parser base class which provides some common support methods used
+    by the SGML/HTML and XHTML parsers."""
+
+    def __init__(self):
+        if self.__class__ is ParserBase:
+            raise RuntimeError(
+                "_markupbase.ParserBase must be subclassed")
+
+    def error(self, message):
+        raise NotImplementedError(
+            "subclasses of ParserBase must override error()")
+
+    def reset(self):
+        self.lineno = 1
+        self.offset = 0
+
+    def getpos(self):
+        """Return current line number and offset."""
+        return self.lineno, self.offset
+
+    # Internal -- update line number and offset.  This should be
+    # called for each piece of data exactly once, in order -- in other
+    # words the concatenation of all the input strings to this
+    # function should be exactly the entire input.
+    def updatepos(self, i, j):
+        if i >= j:
+            return j
+        rawdata = self.rawdata
+        nlines = rawdata.count("\n", i, j)
+        if nlines:
+            self.lineno = self.lineno + nlines
+            pos = rawdata.rindex("\n", i, j) # Should not fail
+            self.offset = j-(pos+1)
+        else:
+            self.offset = self.offset + j-i
+        return j
+
+    _decl_otherchars = ''
+
+    # Internal -- parse declaration (for use by subclasses).
+    def parse_declaration(self, i):
+        # This is some sort of declaration; in "HTML as
+        # deployed," this should only be the document type
+        # declaration ("<!DOCTYPE html...>").
+        # ISO 8879:1986, however, has more complex
+        # declaration syntax for elements in <!...>, including:
+        # --comment--
+        # [marked section]
+        # name in the following list: ENTITY, DOCTYPE, ELEMENT,
+        # ATTLIST, NOTATION, SHORTREF, USEMAP,
+        # LINKTYPE, LINK, IDLINK, USELINK, SYSTEM
+        rawdata = self.rawdata
+        j = i + 2
+        assert rawdata[i:j] == "<!", "unexpected call to parse_declaration"
+        if rawdata[j:j+1] == ">":
+            # the empty comment <!>
+            return j + 1
+        if rawdata[j:j+1] in ("-", ""):
+            # Start of comment followed by buffer boundary,
+            # or just a buffer boundary.
+            return -1
+        # A simple, practical version could look like: ((name|stringlit) S*) + '>'
+        n = len(rawdata)
+        if rawdata[j:j+2] == '--': #comment
+            # Locate --.*-- as the body of the comment
+            return self.parse_comment(i)
+        elif rawdata[j] == '[': #marked section
+            # Locate [statusWord [...arbitrary SGML...]] as the body of the marked section
+            # Where statusWord is one of TEMP, CDATA, IGNORE, INCLUDE, RCDATA
+            # Note that this is extended by Microsoft Office "Save as Web" function
+            # to include [if...] and [endif].
+            return self.parse_marked_section(i)
+        else: #all other declaration elements
+            decltype, j = self._scan_name(j, i)
+        if j < 0:
+            return j
+        if decltype == "doctype":
+            self._decl_otherchars = ''
+        while j < n:
+            c = rawdata[j]
+            if c == ">":
+                # end of declaration syntax
+                data = rawdata[i+2:j]
+                if decltype == "doctype":
+                    self.handle_decl(data)
+                else:
+                    self.unknown_decl(data)
+                return j + 1
+            if c in "\"'":
+                m = _declstringlit_match(rawdata, j)
+                if not m:
+                    return -1 # incomplete
+                j = m.end()
+            elif c in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ":
+                name, j = self._scan_name(j, i)
+            elif c in self._decl_otherchars:
+                j = j + 1
+            elif c == "[":
+                # this could be handled in a separate doctype parser
+                if decltype == "doctype":
+                    j = self._parse_doctype_subset(j + 1, i)
+                elif decltype in ("attlist", "linktype", "link", "element"):
+                    # must tolerate []'d groups in a content model in an element declaration
+                    # also in data attribute specifications of attlist declaration
+                    # also link type declaration subsets in linktype declarations
+                    # also link attribute specification lists in link declarations
+                    self.error("unsupported '[' char in %s declaration" % decltype)
+                else:
+                    self.error("unexpected '[' char in declaration")
+            else:
+                self.error(
+                    "unexpected %r char in declaration" % rawdata[j])
+            if j < 0:
+                return j
+        return -1 # incomplete
+
+    # Internal -- parse a marked section
+    # Override this to handle MS-word extension syntax <![if word]>content<![endif]>
+    def parse_marked_section(self, i, report=1):
+        rawdata= self.rawdata
+        assert rawdata[i:i+3] == '<![', "unexpected call to parse_marked_section()"
+        sectName, j = self._scan_name( i+3, i )
+        if j < 0:
+            return j
+        if sectName in ("temp", "cdata", "ignore", "include", "rcdata"):
+            # look for standard ]]> ending
+            match= _markedsectionclose.search(rawdata, i+3)
+        elif sectName in ("if", "else", "endif"):
+            # look for MS Office ]> ending
+            match= _msmarkedsectionclose.search(rawdata, i+3)
+        else:
+            self.error('unknown status keyword %r in marked section' % rawdata[i+3:j])
+        if not match:
+            return -1
+        if report:
+            j = match.start(0)
+            self.unknown_decl(rawdata[i+3: j])
+        return match.end(0)
+
+    # Internal -- parse comment, return length or -1 if not terminated
+    def parse_comment(self, i, report=1):
+        rawdata = self.rawdata
+        if rawdata[i:i+4] != '<!--':
+            self.error('unexpected call to parse_comment()')
+        match = _commentclose.search(rawdata, i+4)
+        if not match:
+            return -1
+        if report:
+            j = match.start(0)
+            self.handle_comment(rawdata[i+4: j])
+        return match.end(0)
+
+    # Internal -- scan past the internal subset in a <!DOCTYPE declaration,
+    # returning the index just past any whitespace following the trailing ']'.
+    def _parse_doctype_subset(self, i, declstartpos):
+        rawdata = self.rawdata
+        n = len(rawdata)
+        j = i
+        while j < n:
+            c = rawdata[j]
+            if c == "<":
+                s = rawdata[j:j+2]
+                if s == "<":
+                    # end of buffer; incomplete
+                    return -1
+                if s != "<!":
+                    self.updatepos(declstartpos, j + 1)
+                    self.error("unexpected char in internal subset (in %r)" % s)
+                if (j + 2) == n:
+                    # end of buffer; incomplete
+                    return -1
+                if (j + 4) > n:
+                    # end of buffer; incomplete
+                    return -1
+                if rawdata[j:j+4] == "<!--":
+                    j = self.parse_comment(j, report=0)
+                    if j < 0:
+                        return j
+                    continue
+                name, j = self._scan_name(j + 2, declstartpos)
+                if j == -1:
+                    return -1
+                if name not in ("attlist", "element", "entity", "notation"):
+                    self.updatepos(declstartpos, j + 2)
+                    self.error(
+                        "unknown declaration %r in internal subset" % name)
+                # handle the individual names
+                meth = getattr(self, "_parse_doctype_" + name)
+                j = meth(j, declstartpos)
+                if j < 0:
+                    return j
+            elif c == "%":
+                # parameter entity reference
+                if (j + 1) == n:
+                    # end of buffer; incomplete
+                    return -1
+                s, j = self._scan_name(j + 1, declstartpos)
+                if j < 0:
+                    return j
+                if rawdata[j] == ";":
+                    j = j + 1
+            elif c == "]":
+                j = j + 1
+                while j < n and rawdata[j].isspace():
+                    j = j + 1
+                if j < n:
+                    if rawdata[j] == ">":
+                        return j
+                    self.updatepos(declstartpos, j)
+                    self.error("unexpected char after internal subset")
+                else:
+                    return -1
+            elif c.isspace():
+                j = j + 1
+            else:
+                self.updatepos(declstartpos, j)
+                self.error("unexpected char %r in internal subset" % c)
+        # end of buffer reached
+        return -1
+
+    # Internal -- scan past <!ELEMENT declarations
+    def _parse_doctype_element(self, i, declstartpos):
+        name, j = self._scan_name(i, declstartpos)
+        if j == -1:
+            return -1
+        # style content model; just skip until '>'
+        rawdata = self.rawdata
+        if '>' in rawdata[j:]:
+            return rawdata.find(">", j) + 1
+        return -1
+
+    # Internal -- scan past <!ATTLIST declarations
+    def _parse_doctype_attlist(self, i, declstartpos):
+        rawdata = self.rawdata
+        name, j = self._scan_name(i, declstartpos)
+        c = rawdata[j:j+1]
+        if c == "":
+            return -1
+        if c == ">":
+            return j + 1
+        while 1:
+            # scan a series of attribute descriptions; simplified:
+            #   name type [value] [#constraint]
+            name, j = self._scan_name(j, declstartpos)
+            if j < 0:
+                return j
+            c = rawdata[j:j+1]
+            if c == "":
+                return -1
+            if c == "(":
+                # an enumerated type; look for ')'
+                if ")" in rawdata[j:]:
+                    j = rawdata.find(")", j) + 1
+                else:
+                    return -1
+                while rawdata[j:j+1].isspace():
+                    j = j + 1
+                if not rawdata[j:]:
+                    # end of buffer, incomplete
+                    return -1
+            else:
+                name, j = self._scan_name(j, declstartpos)
+            c = rawdata[j:j+1]
+            if not c:
+                return -1
+            if c in "'\"":
+                m = _declstringlit_match(rawdata, j)
+                if m:
+                    j = m.end()
+                else:
+                    return -1
+                c = rawdata[j:j+1]
+                if not c:
+                    return -1
+            if c == "#":
+                if rawdata[j:] == "#":
+                    # end of buffer
+                    return -1
+                name, j = self._scan_name(j + 1, declstartpos)
+                if j < 0:
+                    return j
+                c = rawdata[j:j+1]
+                if not c:
+                    return -1
+            if c == '>':
+                # all done
+                return j + 1
+
+    # Internal -- scan past <!NOTATION declarations
+    def _parse_doctype_notation(self, i, declstartpos):
+        name, j = self._scan_name(i, declstartpos)
+        if j < 0:
+            return j
+        rawdata = self.rawdata
+        while 1:
+            c = rawdata[j:j+1]
+            if not c:
+                # end of buffer; incomplete
+                return -1
+            if c == '>':
+                return j + 1
+            if c in "'\"":
+                m = _declstringlit_match(rawdata, j)
+                if not m:
+                    return -1
+                j = m.end()
+            else:
+                name, j = self._scan_name(j, declstartpos)
+                if j < 0:
+                    return j
+
+    # Internal -- scan past <!ENTITY declarations
+    def _parse_doctype_entity(self, i, declstartpos):
+        rawdata = self.rawdata
+        if rawdata[i:i+1] == "%":
+            j = i + 1
+            while 1:
+                c = rawdata[j:j+1]
+                if not c:
+                    return -1
+                if c.isspace():
+                    j = j + 1
+                else:
+                    break
+        else:
+            j = i
+        name, j = self._scan_name(j, declstartpos)
+        if j < 0:
+            return j
+        while 1:
+            c = self.rawdata[j:j+1]
+            if not c:
+                return -1
+            if c in "'\"":
+                m = _declstringlit_match(rawdata, j)
+                if m:
+                    j = m.end()
+                else:
+                    return -1    # incomplete
+            elif c == ">":
+                return j + 1
+            else:
+                name, j = self._scan_name(j, declstartpos)
+                if j < 0:
+                    return j
+
+    # Internal -- scan a name token and the new position and the token, or
+    # return -1 if we've reached the end of the buffer.
+    def _scan_name(self, i, declstartpos):
+        rawdata = self.rawdata
+        n = len(rawdata)
+        if i == n:
+            return None, -1
+        m = _declname_match(rawdata, i)
+        if m:
+            s = m.group()
+            name = s.strip()
+            if (i + len(s)) == n:
+                return None, -1  # end of buffer
+            return name.lower(), m.end()
+        else:
+            self.updatepos(declstartpos, i)
+            self.error("expected name token at %r"
+                       % rawdata[declstartpos:declstartpos+20])
+
+    # To be overridden -- handlers for unknown objects
+    def unknown_decl(self, data):
+        pass
author	Fred Drake <fdrake@acm.org>	2007-12-07 11:10:11 +0000
committer	Fred Drake <fdrake@acm.org>	2007-12-07 11:10:11 +0000
commit	06d56a591b365a066955988de856b0ee947ae226 (patch)
tree	c5db3f9573569fcc04b2f8d314078981d7491a06 /Lib/_markupbase.py
parent	716ad6b335fbdf5ba53dbdc3a17bd835fed19241 (diff)
download	cpython-06d56a591b365a066955988de856b0ee947ae226.tar.gz