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os: turn Xml_node::Attribute to Xml_attribute

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Moving the XML attribute class to the Genode namespace simplifies the
API.
This commit is contained in:
Norman Feske 2015-03-22 03:26:28 +01:00 committed by Christian Helmuth
parent 394fce110e
commit e1b4408090
1 changed files with 156 additions and 133 deletions
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289
repos/os/include/util/xml_node.h
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@ -17,31 +17,69 @@
#include <util/token.h>
#include <base/exception.h>
namespace Genode { class Xml_node; }
namespace Genode {
class Xml_attribute;
class Xml_node;
}
/**
* Representation of an XML node
* Representation of an XML-node attribute
*
* An attribute has the form 'name="value"'.
*/
class Genode::Xml_node
class Genode::Xml_attribute
{
/**
* 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))); } };
private:
/**
* Define tokenizer that matches XML tags (with hyphens) as identifiers
*/
typedef ::Genode::Token<Scanner_policy_xml_identifier> Token;
/**
* 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))); } };
/**
* Forward declaration needed for befriending Tag with Attribut
*/
class Tag;
/**
* Define tokenizer that matches XML tags (with hyphens) as identifiers
*/
typedef ::Genode::Token<Scanner_policy_xml_identifier> Token;
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'.
*/
Xml_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:
@ -49,136 +87,121 @@ class Genode::Xml_node
** 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"'.
* Return attribute type as null-terminated string
*/
class Attribute
void type(char *dst, size_t max_len) const
{
private:
/*
* 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);
}
Token _name;
Token _value;
/**
* 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; }
friend class Xml_node;
/**
* Return size of value
*/
size_t value_size() const { return _value.len() - 2; }
char const *value_base() const { return _value.start() + 1; }
/*
* 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;
/**
* 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;
}
/**
* 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();
/**
* 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); }
if (_name.next()[0] != '=' || _value.type() != Token::STRING)
throw Invalid_syntax();
}
/**
* 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 token following the attribute declaration
*/
Token _next() const { return _name.next().next().next(); }
/**
* Return next attribute in attribute list
*/
Xml_attribute next() const { return Xml_attribute(_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);
}
/**
* Representation of an XML node
*/
class Genode::Xml_node
{
private:
/**
* 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; }
typedef Xml_attribute::Token Token;
/**
* Return size of value
*/
size_t value_size() const { return _value.len() - 2; }
char const *value_base() const { return _value.start() + 1; }
/**
* Forward declaration needed for befriending Tag with Xml_attribute
*/
class Tag;
/**
* 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;
}
public:
/**
* 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); }
/*********************
** Exception types **
*********************/
/**
* 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;
}
typedef Genode::Exception Exception;
typedef Xml_attribute::Nonexistent_attribute Nonexistent_attribute;
typedef Xml_attribute::Invalid_syntax Invalid_syntax;
/**
* Return next attribute in attribute list
*/
Attribute next() const { return Attribute(_next()); }
};
class Nonexistent_sub_node : public Exception { };
/**
* Type definition for maintaining backward compatibility
*/
typedef Xml_attribute Attribute;
private:
@ -231,7 +254,7 @@ class Genode::Xml_node
Token delimiter = _name.next();
if (supposed_type != END)
try {
for (Attribute a = _name.next(); ; a = a._next())
for (Xml_attribute a = _name.next(); ; a = a._next())
delimiter = a._next();
} catch (Nonexistent_attribute) { }
@ -303,7 +326,7 @@ class Genode::Xml_node
/**
* Return first attribute of tag
*/
Attribute attribute() const { return Attribute(_name.next()); }
Xml_attribute attribute() const { return Xml_attribute(_name.next()); }
};
class Comment
@ -694,10 +717,10 @@ class Genode::Xml_node
* \throw Nonexistent_attribute no such attribute exists
* \return XML attribute
*/
Attribute attribute(unsigned idx) const
Xml_attribute attribute(unsigned idx) const
{
/* get first attribute of the node */
Attribute a = _start_tag.attribute();
Xml_attribute a = _start_tag.attribute();
/* skip attributes until we reach the target index */
for (; idx > 0; idx--)
@ -713,10 +736,10 @@ class Genode::Xml_node
* \throw Nonexistent_attribute no such attribute exists
* \return XML attribute
*/
Attribute attribute(const char *type) const
Xml_attribute attribute(const char *type) const
{
/* iterate, beginning with the first attribute of the node */
for (Attribute a = _start_tag.attribute(); ; a = a.next())
for (Xml_attribute a = _start_tag.attribute(); ; a = a.next())
if (a.has_type(type))
return a;
}