mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-19 21:57:55 +00:00
ca971bbfd8
This patch changes the top-level directory layout as a preparatory step for improving the tools for managing 3rd-party source codes. The rationale is described in the issue referenced below. Issue #1082
734 lines
19 KiB
C++
734 lines
19 KiB
C++
/*
|
|
* \brief XML parser
|
|
* \author Norman Feske
|
|
* \date 2007-08-21
|
|
*/
|
|
|
|
/*
|
|
* Copyright (C) 2007-2013 Genode Labs GmbH
|
|
*
|
|
* This file is part of the Genode OS framework, which is distributed
|
|
* under the terms of the GNU General Public License version 2.
|
|
*/
|
|
|
|
#ifndef _INCLUDE__UTIL__XML_NODE_H_
|
|
#define _INCLUDE__UTIL__XML_NODE_H_
|
|
|
|
#include <util/token.h>
|
|
#include <base/exception.h>
|
|
|
|
namespace Genode {
|
|
|
|
/**
|
|
* Representation of an XML node
|
|
*/
|
|
class Xml_node
|
|
{
|
|
/**
|
|
* Scanner policy that accepts hyphens in identifiers
|
|
*/
|
|
struct Scanner_policy_xml_identifier {
|
|
static bool identifier_char(char c, unsigned i) {
|
|
return is_letter(c) || c == '_' || c == ':'
|
|
|| (i && (c == '-' || c == '.' || is_digit(c))); } };
|
|
|
|
/**
|
|
* Define tokenizer that matches XML tags (with hyphens) as identifiers
|
|
*/
|
|
typedef ::Genode::Token<Scanner_policy_xml_identifier> Token;
|
|
|
|
/**
|
|
* Forward declaration needed for befriending Tag with Attribut
|
|
*/
|
|
class Tag;
|
|
|
|
public:
|
|
|
|
/*********************
|
|
** Exception types **
|
|
*********************/
|
|
|
|
class Exception : public ::Genode::Exception { };
|
|
class Invalid_syntax : public Exception { };
|
|
class Nonexistent_sub_node : public Exception { };
|
|
class Nonexistent_attribute : public Exception { };
|
|
|
|
|
|
/**
|
|
* Representation of an XML-node attribute
|
|
*
|
|
* An attribute has the form 'name="value"'.
|
|
*/
|
|
class Attribute
|
|
{
|
|
private:
|
|
|
|
Token _name;
|
|
Token _value;
|
|
|
|
friend class Xml_node;
|
|
|
|
/*
|
|
* Even though 'Tag' is part of 'Xml_node', the friendship
|
|
* to 'Xml_node' does not apply for 'Tag' when compiling
|
|
* the code with 'gcc-3.4'. Hence, we need to add an
|
|
* explicit friendship to 'Tag'.
|
|
*/
|
|
friend class Tag;
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* This constructor is meant to be used as implicitly to
|
|
* construct an 'Xml_attribute' from a token sequence via an
|
|
* assignment from the leading 'Token'.
|
|
*/
|
|
Attribute(Token t) :
|
|
_name(t.eat_whitespace()), _value(_name.next().next())
|
|
{
|
|
if (_name.type() != Token::IDENT)
|
|
throw Nonexistent_attribute();
|
|
|
|
if (_name.next()[0] != '=' || _value.type() != Token::STRING)
|
|
throw Invalid_syntax();
|
|
}
|
|
|
|
/**
|
|
* Return token following the attribute declaration
|
|
*/
|
|
Token _next() const { return _name.next().next().next(); }
|
|
|
|
public:
|
|
|
|
/**
|
|
* Return attribute type as null-terminated string
|
|
*/
|
|
void type(char *dst, size_t max_len) const
|
|
{
|
|
/*
|
|
* Limit number of characters by token length, take
|
|
* null-termination into account.
|
|
*/
|
|
max_len = min(max_len, _name.len() + 1);
|
|
strncpy(dst, _name.start(), max_len);
|
|
}
|
|
|
|
/**
|
|
* Return true if attribute has specified type
|
|
*/
|
|
bool has_type(const char *type) {
|
|
return strlen(type) == _name.len() &&
|
|
strcmp(type, _name.start(), _name.len()) == 0; }
|
|
|
|
/**
|
|
* Return size of value
|
|
*/
|
|
size_t value_size() const { return _value.len() - 2; }
|
|
char const *value_base() const { return _value.start() + 1; }
|
|
|
|
/**
|
|
* Return attribute value as null-terminated string
|
|
*
|
|
* \return true on success, or
|
|
* false if attribute is invalid
|
|
*/
|
|
bool value(char *dst, size_t max_len) const
|
|
{
|
|
/*
|
|
* The value of 'max_len' denotes the maximum number of
|
|
* characters to be written to 'dst' including the null
|
|
* termination. From the quoted value string, we strip
|
|
* both quote characters and add a null-termination
|
|
* character.
|
|
*/
|
|
max_len = min(max_len, _value.len() - 2 + 1);
|
|
strncpy(dst, _value.start() + 1, max_len);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Return true if attribute has the specified value
|
|
*/
|
|
bool has_value(const char *value) const {
|
|
return strlen(value) == (_value.len() - 2) &&
|
|
!strcmp(value, _value.start() + 1, _value.len() - 2); }
|
|
|
|
/**
|
|
* Return attribute value as typed value
|
|
*
|
|
* \param T type of value to read
|
|
* \return true on success, or
|
|
* false if attribute is invalid or value
|
|
* conversion failed
|
|
*/
|
|
template <typename T>
|
|
bool value(T *out) const
|
|
{
|
|
/*
|
|
* The '_value' token starts with a quote, which we
|
|
* need to skip to access the string. For validating
|
|
* the length, we have to consider both the starting
|
|
* and the trailing quote character.
|
|
*/
|
|
return ascii_to(_value.start() + 1, out) == _value.len() - 2;
|
|
}
|
|
|
|
/**
|
|
* Return next attribute in attribute list
|
|
*/
|
|
Attribute next() const { return Attribute(_next()); }
|
|
};
|
|
|
|
private:
|
|
|
|
class Tag
|
|
{
|
|
public:
|
|
|
|
enum Type { START, END, EMPTY, INVALID };
|
|
|
|
private:
|
|
|
|
Token _token;
|
|
Token _name;
|
|
Type _type;
|
|
|
|
public:
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* \param start first token of the tag
|
|
*
|
|
* At construction time, the validity of the tag is checked and
|
|
* the tag type is determined. A valid tag consists of:
|
|
* # Leading '<' tag delimiter
|
|
* # '/' for marking an end tag
|
|
* # Tag name
|
|
* # Optional attribute sequence (if tag is no end tag)
|
|
* # '/' for marking an empty-element tag (if tag is no end tag)
|
|
* # Closing '>' tag delimiter
|
|
*/
|
|
Tag(Token start) : _token(start), _type(INVALID)
|
|
{
|
|
Type supposed_type = START;
|
|
|
|
if (_token[0] != '<')
|
|
return;
|
|
|
|
if (_token.next()[0] == '/')
|
|
supposed_type = END;
|
|
|
|
if (_token.next().type() != Token::IDENT && _token.next()[0] != '/')
|
|
return;
|
|
|
|
_name = _token.next()[0] == '/' ? _token.next().next() : _token.next();
|
|
if (_name.type() != Token::IDENT)
|
|
return;
|
|
|
|
/* skip attributes to find tag delimiter */
|
|
Token delimiter = _name.next();
|
|
if (supposed_type != END)
|
|
try {
|
|
for (Attribute a = _name.next(); ; a = a._next())
|
|
delimiter = a._next();
|
|
} catch (Nonexistent_attribute) { }
|
|
|
|
delimiter = delimiter.eat_whitespace();
|
|
|
|
/*
|
|
* Now we expect the '>' delimiter. For empty-element tags,
|
|
* the delimiter is prefixed with a '/'.
|
|
*/
|
|
if (delimiter[0] == '/') {
|
|
|
|
/* if a '/' was already at the start, the tag is invalid */
|
|
if (supposed_type == END)
|
|
return;
|
|
|
|
supposed_type = EMPTY;
|
|
|
|
/* skip '/' */
|
|
delimiter = delimiter.next();
|
|
}
|
|
|
|
if (delimiter[0] != '>') return;
|
|
|
|
_type = supposed_type;
|
|
}
|
|
|
|
/**
|
|
* Default constructor produces invalid Tag
|
|
*/
|
|
Tag() : _type(INVALID) { }
|
|
|
|
/**
|
|
* Return type of tag
|
|
*/
|
|
Type type() const { return _type; }
|
|
|
|
/**
|
|
* Return true if tag is the start of a valid XML node
|
|
*/
|
|
bool is_node() const { return _type == START || _type == EMPTY; }
|
|
|
|
/**
|
|
* Return first token of tag
|
|
*/
|
|
Token token() const { return _token; }
|
|
|
|
/**
|
|
* Return name of tag
|
|
*/
|
|
Token name() const { return _name; }
|
|
|
|
/**
|
|
* Return token after the closing tag delimiter
|
|
*/
|
|
Token next_token() const
|
|
{
|
|
/*
|
|
* Search for next closing delimiter, skip potential
|
|
* attributes and '/' delimiter prefix of empty-element
|
|
* tags.
|
|
*/
|
|
Token t = _name;
|
|
for (; t && t[0] != '>'; t = t.next());
|
|
|
|
/* if 't' is invalid, 't.next()' is invalid too */
|
|
return t.next();
|
|
}
|
|
|
|
/**
|
|
* Return first attribute of tag
|
|
*/
|
|
Attribute attribute() const { return Attribute(_name.next()); }
|
|
};
|
|
|
|
class Comment
|
|
{
|
|
private:
|
|
|
|
Token _next; /* token following the comment */
|
|
bool _valid; /* true if comment is well formed */
|
|
|
|
/**
|
|
* Check if token sequence matches specified character sequence
|
|
*
|
|
* \param t start of token sequence
|
|
* \param s null-terminated character sequence
|
|
*/
|
|
static bool _match(Token t, const char *s)
|
|
{
|
|
for (int i = 0; s[i]; t = t.next(), i++)
|
|
if (t[0] != s[i])
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
public:
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* \param start first token of the comment tag
|
|
*/
|
|
Comment(Token t) : _valid(false)
|
|
{
|
|
/* check for comment-start tag */
|
|
if (!_match(t, "<!--"))
|
|
return;
|
|
|
|
/* search for comment-end tag */
|
|
for ( ; t && !_match(t, "-->"); t = t.next());
|
|
|
|
if (t.type() == Token::END)
|
|
return;
|
|
|
|
_next = t.next().next().next();
|
|
_valid = true;
|
|
}
|
|
|
|
/**
|
|
* Default constructor produces invalid Comment
|
|
*/
|
|
Comment() : _valid(false) { }
|
|
|
|
/**
|
|
* Return true if comment is valid
|
|
*/
|
|
bool valid() const { return _valid; }
|
|
|
|
/**
|
|
* Return token after the closing comment delimiter
|
|
*/
|
|
Token next_token() const { return _next; }
|
|
};
|
|
|
|
const char *_addr; /* first character of XML data */
|
|
size_t _max_len; /* length of XML data in characters */
|
|
int _num_sub_nodes; /* number of immediate sub nodes */
|
|
Tag _start_tag;
|
|
Tag _end_tag;
|
|
|
|
/**
|
|
* Search for end tag of XML node and initialize '_num_sub_nodes'
|
|
*
|
|
* \return end tag or invalid tag
|
|
*
|
|
* The function searches for a end tag that matches the same
|
|
* depth level and the same name as the start tag of the XML
|
|
* node. If the XML structure is invalid, the search results
|
|
* is an invalid Tag.
|
|
*
|
|
* During the search, the function also counts the number of
|
|
* immediate sub nodes.
|
|
*/
|
|
Tag _init_end_tag()
|
|
{
|
|
/*
|
|
* If the start tag is invalid or an empty-element tag,
|
|
* we use the same tag as end tag.
|
|
*/
|
|
if (_start_tag.type() != Tag::START)
|
|
return _start_tag;
|
|
|
|
int depth = 1;
|
|
Token curr_token = _start_tag.next_token();
|
|
|
|
while (curr_token.type() != Token::END) {
|
|
|
|
/* eat XML comment */
|
|
Comment curr_comment(curr_token);
|
|
if (curr_comment.valid()) {
|
|
curr_token = curr_comment.next_token();
|
|
continue;
|
|
}
|
|
|
|
/* skip all tokens that are no tags */
|
|
Tag curr_tag(curr_token);
|
|
if (curr_tag.type() == Tag::INVALID) {
|
|
curr_token = curr_token.next();
|
|
continue;
|
|
}
|
|
|
|
/* count sub nodes at depth 1 */
|
|
if (depth == 1 && curr_tag.is_node())
|
|
_num_sub_nodes++;
|
|
|
|
/* keep track of the current depth */
|
|
depth += (curr_tag.type() == Tag::START);
|
|
depth -= (curr_tag.type() == Tag::END);
|
|
|
|
/* within sub nodes, continue after current token */
|
|
if (depth > 0) {
|
|
|
|
/* continue search with token after current tag */
|
|
curr_token = curr_tag.next_token();
|
|
continue;
|
|
}
|
|
|
|
/* reaching the same depth as the start tag */
|
|
const char *start_name = _start_tag.name().start();
|
|
size_t start_len = _start_tag.name().len();
|
|
const char *curr_name = curr_tag.name().start();
|
|
size_t curr_len = curr_tag.name().len();
|
|
|
|
/* on mismatch of start tag and end tag, return invalid tag */
|
|
if (start_len != curr_len
|
|
|| strcmp(start_name, curr_name, curr_len))
|
|
return Tag();
|
|
|
|
/* end tag corresponds to start tag */
|
|
return curr_tag;
|
|
}
|
|
return Tag();
|
|
}
|
|
|
|
/**
|
|
* Find next non-whitespace and non-comment token
|
|
*/
|
|
static Token eat_whitespaces_and_comments(Token t)
|
|
{
|
|
while (true) {
|
|
|
|
t = t.eat_whitespace();
|
|
|
|
/* eat comment */
|
|
Comment comment(t);
|
|
if (comment.valid()) {
|
|
t = comment.next_token();
|
|
continue;
|
|
}
|
|
|
|
break;
|
|
}
|
|
return t;
|
|
}
|
|
|
|
/**
|
|
* Create sub node from XML node
|
|
*
|
|
* \throw Nonexistent_sub_node
|
|
* \throw Invalid_syntax
|
|
*/
|
|
Xml_node _sub_node(const char *at) const
|
|
{
|
|
if (at < addr() || (size_t)(at - addr()) >= _max_len)
|
|
throw Nonexistent_sub_node();
|
|
|
|
return Xml_node(at, _max_len - (at - addr()));
|
|
}
|
|
|
|
public:
|
|
|
|
/**
|
|
* Constructor
|
|
*
|
|
* The constructor validates if the start tag has a
|
|
* matching end tag of the same depth and counts
|
|
* the number of immediate sub nodes.
|
|
*/
|
|
Xml_node(const char *addr, size_t max_len = ~0UL) :
|
|
_addr(addr),
|
|
_max_len(max_len),
|
|
_num_sub_nodes(0),
|
|
_start_tag(eat_whitespaces_and_comments(Token(addr, max_len))),
|
|
_end_tag(_init_end_tag())
|
|
{
|
|
/* check validity of XML node */
|
|
if (_start_tag.type() == Tag::EMPTY) return;
|
|
if (_start_tag.type() == Tag::START && _end_tag.type() == Tag::END) return;
|
|
|
|
throw Invalid_syntax();
|
|
}
|
|
|
|
/**
|
|
* Request type name of XML node as null-terminated string
|
|
*/
|
|
void type_name(char *dst, size_t max_len) const {
|
|
_start_tag.name().string(dst, max_len); }
|
|
|
|
/**
|
|
* Return true if tag is of specified type
|
|
*/
|
|
bool has_type(const char *type) const {
|
|
return (!strcmp(type, _start_tag.name().start(),
|
|
_start_tag.name().len())
|
|
&& strlen(type) == _start_tag.name().len()); }
|
|
|
|
/**
|
|
* Request content of XML node as null-terminated string
|
|
*/
|
|
void value(char *dst, size_t max_len) const {
|
|
max_len = min(content_size() + 1, min(max_len, _max_len));
|
|
strncpy(dst, content_addr(), max_len); }
|
|
|
|
/**
|
|
* Read content as typed value from XML node
|
|
*
|
|
* \param T type of value to read from XML node
|
|
* \param out resulting value
|
|
* \return true on success
|
|
*/
|
|
template <typename T>
|
|
bool value(T *out) const {
|
|
return ascii_to(content_addr(), out) == content_size(); }
|
|
|
|
/**
|
|
* Return begin of node including the start tag
|
|
*/
|
|
const char *addr() const { return _addr; }
|
|
|
|
/**
|
|
* Return size of node including start and end tags
|
|
*/
|
|
size_t size() const { return _end_tag.next_token().start() - addr(); }
|
|
|
|
/**
|
|
* Return begin of node content as an opaque string
|
|
*
|
|
* Note that the returned string is not null-terminated as it
|
|
* points directly into a sub range of the unmodified Xml_node
|
|
* address range.
|
|
*
|
|
* XXX This function is deprecated. Use 'content_base()' instead.
|
|
*/
|
|
char *content_addr() const { return _start_tag.next_token().start(); }
|
|
|
|
/**
|
|
* Return pointer to start of content
|
|
*/
|
|
char const *content_base() const { return content_addr(); }
|
|
|
|
/**
|
|
* Return size of node content
|
|
*/
|
|
size_t content_size() const
|
|
{
|
|
if (_start_tag.type() == Tag::EMPTY)
|
|
return 0;
|
|
|
|
return _end_tag.token().start() - content_addr();
|
|
}
|
|
|
|
/**
|
|
* Return the number of the XML node's immediate sub nodes
|
|
*/
|
|
size_t num_sub_nodes() const { return _num_sub_nodes; }
|
|
|
|
/**
|
|
* Return XML node following the current one
|
|
*
|
|
* \throw Nonexistent_sub_node sub sequent node does not exist
|
|
*/
|
|
Xml_node next() const
|
|
{
|
|
Token after_node = _end_tag.next_token();
|
|
after_node = eat_whitespaces_and_comments(after_node);
|
|
try { return _sub_node(after_node.start()); }
|
|
catch (Invalid_syntax) { throw Nonexistent_sub_node(); }
|
|
}
|
|
|
|
/**
|
|
* Return next XML node of specified type
|
|
*
|
|
* \param type type of XML node, or
|
|
* 0 for matching any type
|
|
*/
|
|
Xml_node next(const char *type) const
|
|
{
|
|
Xml_node node = next();
|
|
for (; type && !node.has_type(type); node = node.next());
|
|
return node;
|
|
}
|
|
|
|
/**
|
|
* Return true if node is the last of a node sequence
|
|
*/
|
|
bool is_last(const char *type = 0) const
|
|
{
|
|
try { next(type); return false; }
|
|
catch (Nonexistent_sub_node) { return true; }
|
|
}
|
|
|
|
/**
|
|
* Return sub node with specified index
|
|
*
|
|
* \param idx index of sub node,
|
|
* default is the first node
|
|
* \throw Nonexistent_sub_node no such sub node exists
|
|
*/
|
|
Xml_node sub_node(unsigned idx = 0U) const
|
|
{
|
|
/* look up node at specified index */
|
|
try {
|
|
Xml_node curr_node = _sub_node(content_addr());
|
|
for (; idx > 0; idx--)
|
|
curr_node = curr_node.next();
|
|
return curr_node;
|
|
} catch (Invalid_syntax) { }
|
|
|
|
throw Nonexistent_sub_node();
|
|
}
|
|
|
|
/**
|
|
* Return first sub node that matches the specified type
|
|
*
|
|
* \throw Nonexistent_sub_node no such sub_node exists
|
|
*/
|
|
Xml_node sub_node(const char *type) const
|
|
{
|
|
/* search for sub node of specified type */
|
|
try {
|
|
Xml_node curr_node = _sub_node(content_addr());
|
|
for ( ; true; curr_node = curr_node.next())
|
|
if (curr_node.has_type(type))
|
|
return curr_node;
|
|
} catch (...) { }
|
|
|
|
throw Nonexistent_sub_node();
|
|
}
|
|
|
|
/**
|
|
* Return Nth attribute of XML node
|
|
*
|
|
* \param idx attribute index,
|
|
* first attribute has index 0
|
|
* \throw Nonexistent_attribute no such attribute exists
|
|
* \return XML attribute
|
|
*/
|
|
Attribute attribute(unsigned idx) const
|
|
{
|
|
/* get first attribute of the node */
|
|
Attribute a = _start_tag.attribute();
|
|
|
|
/* skip attributes until we reach the target index */
|
|
for (; idx > 0; idx--)
|
|
a = a._next();
|
|
|
|
return a;
|
|
}
|
|
|
|
/**
|
|
* Return attribute of specified type
|
|
*
|
|
* \param type name of attribute type
|
|
* \throw Nonexistent_attribute no such attribute exists
|
|
* \return XML attribute
|
|
*/
|
|
Attribute attribute(const char *type) const
|
|
{
|
|
/* iterate, beginning with the first attribute of the node */
|
|
for (Attribute a = _start_tag.attribute(); ; a = a.next())
|
|
if (a.has_type(type))
|
|
return a;
|
|
}
|
|
|
|
/**
|
|
* Shortcut for reading an attribute value from XML node
|
|
*
|
|
* \param type attribute name
|
|
* \param default_value value returned if no attribute with the
|
|
* name 'type' is present.
|
|
* \return attribute value or specified default value
|
|
*
|
|
* Without this shortcut, attribute values can be obtained by
|
|
* 'node.attribute(...).value(...)' only. Because the attribute
|
|
* lookup may throw a 'Nonexistent_attribute' exception, code that
|
|
* reads optional attributes (those with default values) has to
|
|
* handle the exception accordingly. Such code tends to become
|
|
* clumsy, in particular when many attributes are processed in a
|
|
* subsequent fashion. This function template relieves the XML node
|
|
* user from implementing the exception handling manually.
|
|
*/
|
|
template <typename T>
|
|
inline T attribute_value(char const *type, T default_value) const
|
|
{
|
|
T result = default_value;
|
|
try { attribute(type).value(&result); } catch (...) { }
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Return true if attribute of specified type exists
|
|
*/
|
|
inline bool has_attribute(char const *type) const
|
|
{
|
|
try { attribute(type); return true; } catch (...) { }
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Return true if sub node of specified type exists
|
|
*/
|
|
inline bool has_sub_node(char const *type) const
|
|
{
|
|
try { sub_node(type); return true; } catch (...) { }
|
|
return false;
|
|
}
|
|
};
|
|
}
|
|
|
|
#endif /* _INCLUDE__UTIL__XML_NODE_H_ */
|