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Diffstat (limited to 'libcutl/cutl/xml/parser.cxx')
| -rw-r--r-- | libcutl/cutl/xml/parser.cxx | 827 |
1 files changed, 827 insertions, 0 deletions
diff --git a/libcutl/cutl/xml/parser.cxx b/libcutl/cutl/xml/parser.cxx new file mode 100644 index 0000000..219fb00 --- /dev/null +++ b/libcutl/cutl/xml/parser.cxx @@ -0,0 +1,827 @@ +// file : cutl/xml/parser.cxx +// copyright : Copyright (c) 2009-2013 Code Synthesis Tools CC +// license : MIT; see accompanying LICENSE file + +#include <new> // std::bad_alloc +#include <cassert> +#include <cstring> // std::strchr +#include <istream> +#include <ostream> +#include <sstream> + +#include <cutl/xml/parser.hxx> + +using namespace std; + +namespace cutl +{ + namespace xml + { + // parsing + // + parsing:: + ~parsing () throw () {} + + parsing:: + parsing (const string& n, + unsigned long long l, + unsigned long long c, + const string& d) + : name_ (n), line_ (l), column_ (c), description_ (d) + { + init (); + } + + parsing:: + parsing (const parser& p, const std::string& d) + : name_ (p.input_name ()), + line_ (p.line ()), + column_ (p.column ()), + description_ (d) + { + init (); + } + + void parsing:: + init () + { + ostringstream os; + if (!name_.empty ()) + os << name_ << ':'; + os << line_ << ':' << column_ << ": error: " << description_; + what_ = os.str (); + } + + char const* parsing:: + what () const throw () + { + return what_.c_str (); + } + + // parser::event_type + // + static const char* parser_event_str[] = + { + "start element", + "end element", + "start attribute", + "end attribute", + "characters", + "start namespace declaration", + "end namespace declaration", + "end of file" + }; + + ostream& + operator<< (ostream& os, parser::event_type e) + { + return os << parser_event_str[e]; + } + + // parser + // + parser:: + ~parser () + { + if (p_ != 0) + XML_ParserFree (p_); + } + + parser:: + parser (istream& is, const string& iname, feature_type f) + : is_ (is), iname_ (iname), feature_ (f), + depth_ (0), state_ (state_next), event_ (eof), queue_ (eof), + pqname_ (&qname_), pvalue_ (&value_), + attr_i_ (0), start_ns_i_ (0), end_ns_i_ (0) + { + if ((feature_ & receive_attributes_map) != 0 && + (feature_ & receive_attributes_event) != 0) + feature_ &= ~receive_attributes_map; + + // Allocate the parser. Make sure nothing else can throw after + // this call since otherwise we will leak it. + // + p_ = XML_ParserCreateNS (0, XML_Char (' ')); + + if (p_ == 0) + throw bad_alloc (); + + // Get prefixes in addition to namespaces and local names. + // + XML_SetReturnNSTriplet (p_, true); + + // Set handlers. + // + XML_SetUserData(p_, this); + + if ((f & receive_elements) != 0) + { + XML_SetStartElementHandler (p_, &start_element_); + XML_SetEndElementHandler (p_, &end_element_); + } + + if ((f & receive_characters) != 0) + XML_SetCharacterDataHandler (p_, &characters_); + + if ((f & receive_namespace_decls) != 0) + XML_SetNamespaceDeclHandler (p_, + &start_namespace_decl_, + &end_namespace_decl_); + } + + void parser:: + handle_error () + { + XML_Error e (XML_GetErrorCode (p_)); + + if (e == XML_ERROR_ABORTED) + { + // For now we only abort the parser in the characters_() handler. + // + switch (content ()) + { + case empty: + throw parsing (*this, "character in empty content"); + case complex: + throw parsing (*this, "character in complex content"); + default: + assert (false); + } + } + else + throw parsing (iname_, + XML_GetCurrentLineNumber (p_), + XML_GetCurrentColumnNumber (p_), + XML_ErrorString (e)); + } + + struct stream_exception_controller + { + ~stream_exception_controller () + { + istream::iostate s = is_.rdstate (); + s &= ~istream::failbit; + + // If our error state (sans failbit) intersects with the + // exception state then that means we have an active + // exception and changing error/exception state will + // cause another to be thrown. + // + if (!(old_state_ & s)) + { + // Clear failbit if it was caused by eof. + // + if (is_.fail () && is_.eof ()) + is_.clear (s); + + is_.exceptions (old_state_); + } + } + + stream_exception_controller (istream& is) + : is_ (is), old_state_ (is_.exceptions ()) + { + is_.exceptions (old_state_ & ~istream::failbit); + } + + private: + stream_exception_controller (const stream_exception_controller&); + + stream_exception_controller& + operator= (const stream_exception_controller&); + + private: + istream& is_; + istream::iostate old_state_; + }; + + const string& parser:: + attribute (const qname_type& qn) const + { + if (const element_entry* e = get_element ()) + { + attribute_map_type::const_iterator i (e->attr_map_.find (qn)); + + if (i != e->attr_map_.end ()) + { + if (!i->second.handled) + { + i->second.handled = true; + e->attr_unhandled_--; + } + return i->second.value; + } + } + + throw parsing (*this, "attribute '" + qn.string () + "' expected"); + } + + string parser:: + attribute (const qname_type& qn, const string& dv) const + { + if (const element_entry* e = get_element ()) + { + attribute_map_type::const_iterator i (e->attr_map_.find (qn)); + + if (i != e->attr_map_.end ()) + { + if (!i->second.handled) + { + i->second.handled = true; + e->attr_unhandled_--; + } + return i->second.value; + } + } + + return dv; + } + + bool parser:: + attribute_present (const qname_type& qn) const + { + if (const element_entry* e = get_element ()) + { + attribute_map_type::const_iterator i (e->attr_map_.find (qn)); + + if (i != e->attr_map_.end ()) + { + if (!i->second.handled) + { + i->second.handled = true; + e->attr_unhandled_--; + } + return true; + } + } + + return false; + } + + void parser:: + next_expect (event_type e) + { + if (next () != e) + throw parsing (*this, string (parser_event_str[e]) + " expected"); + } + + void parser:: + next_expect (event_type e, const string& ns, const string& n) + { + if (next () != e || namespace_ () != ns || name () != n) + throw parsing (*this, + string (parser_event_str[e]) + " '" + + qname_type (ns, n).string () + "' expected"); + } + + const parser::element_entry* parser:: + get_element () const + { + // The start_element_() Expat handler may have already provisioned + // an entry in the element stack. In this case, we need to get the + // one before it, if any. + // + const element_entry* r (0); + element_state::size_type n (element_state_.size ()); + if (n != 0) + { + n--; + if (element_state_[n].depth == depth_) + r = &element_state_[n]; + else if (n != 0 && element_state_[n].depth > depth_) + { + n--; + if (element_state_[n].depth == depth_) + r = &element_state_[n]; + } + } + return r; + } + + void parser:: + pop_element () + { + // Make sure there are no unhandled attributes left. + // + const element_entry& e (element_state_.back ()); + if (e.attr_unhandled_ != 0) + { + // Find the first unhandled attribute and report it. + // + for (attribute_map_type::const_iterator i (e.attr_map_.begin ()); + i != e.attr_map_.end (); ++i) + { + if (!i->second.handled) + throw parsing ( + *this, "unexpected attribute '" + i->first.string () + "'"); + } + assert (false); + } + + element_state_.pop_back (); + } + + parser::event_type parser:: + next_ (bool peek) + { + event_type e (next_body ()); + + // Content-specific processing. Note that we handle characters in the + // characters_() Expat handler for two reasons. Firstly, it is faster + // to ignore the whitespaces at the source. Secondly, this allows us + // to distinguish between element and attribute characters. We can + // move this processing to the handler because the characters event + // is never queued. + // + switch (e) + { + case end_element: + { + // If this is a peek, then avoid popping the stack just yet. + // This way, the attribute map will still be valid until we + // call next(). + // + if (!peek) + { + if (!element_state_.empty () && + element_state_.back ().depth == depth_) + pop_element (); + + depth_--; + } + break; + } + case start_element: + { + const element_entry* e (get_element ()); + switch (e != 0 ? e->content : mixed) + { + case empty: + throw parsing (*this, "element in empty content"); + case simple: + throw parsing (*this, "element in simple content"); + default: + break; + } + + // If this is a peek, then delay adjusting the depth. + // + if (!peek) + depth_++; + + break; + } + default: + break; + } + + return e; + } + + parser::event_type parser:: + next_body () + { + // See if we have any start namespace declarations we need to return. + // + if (start_ns_i_ < start_ns_.size ()) + { + // Based on the previous event determine what's the next one must be. + // + switch (event_) + { + case start_namespace_decl: + { + if (++start_ns_i_ == start_ns_.size ()) + { + start_ns_i_ = 0; + start_ns_.clear (); + pqname_ = &qname_; + break; // No more declarations. + } + // Fall through. + } + case start_element: + { + event_ = start_namespace_decl; + pqname_ = &start_ns_[start_ns_i_]; + return event_; + } + default: + { + assert (false); + return event_ = eof; + } + } + } + + // See if we have any attributes we need to return as events. + // + if (attr_i_ < attr_.size ()) + { + // Based on the previous event determine what's the next one must be. + // + switch (event_) + { + case start_attribute: + { + event_ = characters; + pvalue_ = &attr_[attr_i_].value; + return event_; + } + case characters: + { + event_ = end_attribute; // Name is already set. + return event_; + } + case end_attribute: + { + if (++attr_i_ == attr_.size ()) + { + attr_i_ = 0; + attr_.clear (); + pqname_ = &qname_; + pvalue_ = &value_; + break; // No more attributes. + } + // Fall through. + } + case start_element: + case start_namespace_decl: + { + event_ = start_attribute; + pqname_ = &attr_[attr_i_].qname; + return event_; + } + default: + { + assert (false); + return event_ = eof; + } + } + } + + // See if we have any end namespace declarations we need to return. + // + if (end_ns_i_ < end_ns_.size ()) + { + // Based on the previous event determine what's the next one must be. + // + switch (event_) + { + case end_namespace_decl: + { + if (++end_ns_i_ == end_ns_.size ()) + { + end_ns_i_ = 0; + end_ns_.clear (); + pqname_ = &qname_; + break; // No more declarations. + } + // Fall through. + } + // The end namespace declaration comes before the end element + // which means it can follow pretty much any other event. + // + default: + { + event_ = end_namespace_decl; + pqname_ = &end_ns_[end_ns_i_]; + return event_; + } + } + } + + // Check the queue. + // + if (queue_ != eof) + { + event_ = queue_; + queue_ = eof; + return event_; + } + + XML_ParsingStatus ps; + XML_GetParsingStatus (p_, &ps); + + switch (ps.parsing) + { + case XML_INITIALIZED: + { + // As if we finished the previous chunk. + break; + } + case XML_PARSING: + { + assert (false); + return event_ = eof; + } + case XML_FINISHED: + { + return event_ = eof; + } + case XML_SUSPENDED: + { + switch (XML_ResumeParser (p_)) + { + case XML_STATUS_SUSPENDED: + { + // If the parser is again in the suspended state, then + // that means we have the next event. + // + return event_; + } + case XML_STATUS_OK: + { + // Otherwise, we need to get and parse the next chunk of data + // unless this was the last chunk, in which case this is eof. + // + if (ps.finalBuffer) + return event_ = eof; + + break; + } + case XML_STATUS_ERROR: + handle_error (); + } + + break; + } + } + + // Get and parse the next chunk of data until we get the next event + // or reach eof. + // + event_ = eof; + XML_Status s; + do + { + const size_t cap (4096); + + char* b (static_cast<char*> (XML_GetBuffer (p_, cap))); + if (b == 0) + throw bad_alloc (); + + // Temporarily unset the exception failbit. Also clear the fail bit + // when we reset the old state if it was caused by eof. + // + { + stream_exception_controller sec (is_); + is_.read (b, static_cast<streamsize> (cap)); + } + + s = XML_ParseBuffer (p_, static_cast<int> (is_.gcount ()), is_.eof ()); + + if (s == XML_STATUS_ERROR) + handle_error (); + + } while (s != XML_STATUS_SUSPENDED && !is_.eof ()); + + return event_; + } + + static void + split_name (const XML_Char* s, qname& qn) + { + string& ns (qn.namespace_ ()); + string& name (qn.name ()); + string& prefix (qn.prefix ()); + + const char* p (strchr (s, ' ')); + + if (p == 0) + { + ns.clear (); + name = s; + prefix.clear (); + } + else + { + ns.assign (s, 0, p - s); + + s = p + 1; + p = strchr (s, ' '); + + if (p == 0) + { + name = s; + prefix.clear (); + } + else + { + name.assign (s, 0, p - s); + prefix = p + 1; + } + } + } + + void XMLCALL parser:: + start_element_ (void* v, const XML_Char* name, const XML_Char** atts) + { + parser& p (*static_cast<parser*> (v)); + + XML_ParsingStatus ps; + XML_GetParsingStatus (p.p_, &ps); + + // Expat has a (mis)-feature of a possibily calling handlers even + // after the non-resumable XML_StopParser call. + // + if (ps.parsing == XML_FINISHED) + return; + + // Cannot be a followup event. + // + assert (ps.parsing == XML_PARSING); + + p.event_ = start_element; + split_name (name, p.qname_); + + p.line_ = XML_GetCurrentLineNumber (p.p_); + p.column_ = XML_GetCurrentColumnNumber (p.p_); + + // Handle attributes. + // + if (*atts != 0) + { + bool am ((p.feature_ & receive_attributes_map) != 0); + bool ae ((p.feature_ & receive_attributes_event) != 0); + + // Provision an entry for this element. + // + element_entry* pe (0); + if (am) + { + p.element_state_.push_back (element_entry (p.depth_ + 1)); + pe = &p.element_state_.back (); + } + + if (am || ae) + { + for (; *atts != 0; atts += 2) + { + if (am) + { + qname_type qn; + split_name (*atts, qn); + attribute_map_type::value_type v (qn, attribute_value_type ()); + v.second.value = *(atts + 1); + v.second.handled = false; + pe->attr_map_.insert (v); + } + else + { + p.attr_.push_back (attribute_type ()); + split_name (*atts, p.attr_.back ().qname); + p.attr_.back ().value = *(atts + 1); + } + } + + if (am) + pe->attr_unhandled_ = pe->attr_map_.size (); + } + } + + XML_StopParser (p.p_, true); + } + + void XMLCALL parser:: + end_element_ (void* v, const XML_Char* name) + { + parser& p (*static_cast<parser*> (v)); + + XML_ParsingStatus ps; + XML_GetParsingStatus (p.p_, &ps); + + // Expat has a (mis)-feature of a possibily calling handlers even + // after the non-resumable XML_StopParser call. + // + if (ps.parsing == XML_FINISHED) + return; + + // This can be a followup event for empty elements (<foo/>). In this + // case the element name is already set. + // + if (ps.parsing != XML_PARSING) + p.queue_ = end_element; + else + { + // We may also have the end namespace declaration events which + // should come before the end element. If that's the case, then + // queue the end element and return the end namespace as the next + // event. + // + if (p.end_ns_i_ < p.end_ns_.size ()) + { + p.event_ = end_namespace_decl; + p.queue_ = end_element; + } + else + p.event_ = end_element; + + split_name (name, p.qname_); + + p.line_ = XML_GetCurrentLineNumber (p.p_); + p.column_ = XML_GetCurrentColumnNumber (p.p_); + + XML_StopParser (p.p_, true); + } + } + + void XMLCALL parser:: + characters_ (void* v, const XML_Char* s, int n) + { + parser& p (*static_cast<parser*> (v)); + + XML_ParsingStatus ps; + XML_GetParsingStatus (p.p_, &ps); + + // Expat has a (mis)-feature of a possibily calling handlers even + // after the non-resumable XML_StopParser call. + // + if (ps.parsing == XML_FINISHED) + return; + + // If this is empty or complex content, see if these are whitespaces. + // + switch (p.content ()) + { + case empty: + case complex: + { + for (int i (0); i != n; ++i) + { + char c (s[i]); + if (c == 0x20 || c == 0x0A || c == 0x0D || c == 0x09) + continue; + + // It would have been easier to throw the exception directly, + // however, the Expat code is most likely not exception safe. + // + p.line_ = XML_GetCurrentLineNumber (p.p_); + p.column_ = XML_GetCurrentColumnNumber (p.p_); + XML_StopParser (p.p_, false); + break; + } + return; + } + default: + break; + } + + // This can be a followup event for another character event. In + // this case simply append the data. + // + if (ps.parsing != XML_PARSING) + { + assert (p.event_ == characters); + p.value_.append (s, n); + } + else + { + p.event_ = characters; + p.value_.assign (s, n); + + p.line_ = XML_GetCurrentLineNumber (p.p_); + p.column_ = XML_GetCurrentColumnNumber (p.p_); + + XML_StopParser (p.p_, true); + } + } + + void XMLCALL parser:: + start_namespace_decl_ (void* v, const XML_Char* prefix, const XML_Char* ns) + { + parser& p (*static_cast<parser*> (v)); + + XML_ParsingStatus ps; + XML_GetParsingStatus (p.p_, &ps); + + // Expat has a (mis)-feature of a possibily calling handlers even + // after the non-resumable XML_StopParser call. + // + if (ps.parsing == XML_FINISHED) + return; + + p.start_ns_.push_back (qname_type ()); + p.start_ns_.back ().prefix () = (prefix != 0 ? prefix : ""); + p.start_ns_.back ().namespace_ () = (ns != 0 ? ns : ""); + } + + void XMLCALL parser:: + end_namespace_decl_ (void* v, const XML_Char* prefix) + { + parser& p (*static_cast<parser*> (v)); + + XML_ParsingStatus ps; + XML_GetParsingStatus (p.p_, &ps); + + // Expat has a (mis)-feature of a possibily calling handlers even + // after the non-resumable XML_StopParser call. + // + if (ps.parsing == XML_FINISHED) + return; + + p.end_ns_.push_back (qname_type ()); + p.end_ns_.back ().prefix () = (prefix != 0 ? prefix : ""); + } + } +} |