openMSX
Public Member Functions | List of all members
XMLOutputStream< Operations > Class Template Reference

'XMLOutputStream' is a helper to write an XML file in a streaming way. More...

#include <XMLOutputStream.hh>

Inheritance diagram for XMLOutputStream< Operations >:
Inheritance graph
[legend]

Public Member Functions

 XMLOutputStream (Operations &ops_)
 
void begin (std::string_view tag)
 
void attribute (std::string_view name, std::string_view value)
 
void data (std::string_view value)
 
void end (std::string_view tag)
 

Detailed Description

template<typename Operations>
class XMLOutputStream< Operations >

'XMLOutputStream' is a helper to write an XML file in a streaming way.

That is: all information must be provided in the exact same order as it appears in the output. So attributes for a tag must be provided before the data for that tag. It's not possible to go back to an earlier tag and add/change/remove attributes or data, nor is it possible to add/remove subtags to already streamed tags.

In other words: this helper class immediately write the provided data to the output stream, and it cannot make changes to already outputted data. So basically the only thing this class does is take care of the syntax details and formatting of the XML file. The main advantage of this class is that it's very cheap: it does not need to keep (much) state in memory (e.g. it does not build the whole XML tree in memory and then dump it all at the end).

One limitation of this helper is that it does not support mixed-content tags. A tag either contains data or it contains subtags, but not both (neither data nor subtags is fine).


After instantiation of the 'XMLOutputStream', you must call the begin(), attribute(), data(), end() methods. These directly correspond to elements in the XML file, so the meaning should be clear. There are also constraints on the order in which these methods are allowed to be called:


'XMLOutputStream' is templatized on an 'Operations' type. This must be a class that implements the following 3 methods: struct MyOperations { void write(const char* buf, size_t len); void write1(char c); void check(bool condition) const; };

The write() and write1() methods write data (e.g. to a file). Either a whole buffer or a single character. In some implementations it's more efficient to write a single char than to write a buffer of length 1, but in your implementation feel free to implement write1() as: write1(char c) { write(&c, 1); }

The check() method should be implemented as: assert(condition); Though in the unittests we instead make this throw an exception so that we can test the error cases.

Definition at line 70 of file XMLOutputStream.hh.

Constructor & Destructor Documentation

◆ XMLOutputStream()

template<typename Operations >
XMLOutputStream< Operations >::XMLOutputStream ( Operations &  ops_)
inline

Definition at line 73 of file XMLOutputStream.hh.

Member Function Documentation

◆ attribute()

template<typename Writer >
void XMLOutputStream< Writer >::attribute ( std::string_view  name,
std::string_view  value 
)

Definition at line 120 of file XMLOutputStream.hh.

Referenced by TEST_CASE().

◆ begin()

template<typename Writer >
void XMLOutputStream< Writer >::begin ( std::string_view  tag)

Definition at line 103 of file XMLOutputStream.hh.

Referenced by TEST_CASE().

◆ data()

template<typename Writer >
void XMLOutputStream< Writer >::data ( std::string_view  value)

Definition at line 132 of file XMLOutputStream.hh.

Referenced by TEST_CASE().

◆ end()

template<typename Writer >
void XMLOutputStream< Writer >::end ( std::string_view  tag)

Definition at line 145 of file XMLOutputStream.hh.

Referenced by TEST_CASE().


The documentation for this class was generated from the following file: