dyaml/source/dyaml/dumper.d
2014-07-19 04:17:18 +02:00

356 lines
11 KiB
D

// Copyright Ferdinand Majerech 2011.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
/**
* YAML _dumper.
*
* Code based on $(LINK2 http://www.pyyaml.org, PyYAML).
*/
module dyaml.dumper;
import std.stream;
import std.typecons;
import dyaml.anchor;
import dyaml.emitter;
import dyaml.encoding;
import dyaml.event;
import dyaml.exception;
import dyaml.linebreak;
import dyaml.node;
import dyaml.representer;
import dyaml.resolver;
import dyaml.serializer;
import dyaml.tagdirective;
/**
* Dumps YAML documents to files or streams.
*
* User specified Representer and/or Resolver can be used to support new
* tags / data types.
*
* Setters are provided to affect output details (style, encoding, etc.).
*
* Examples:
*
* Write to a file:
* --------------------
* auto node = Node([1, 2, 3, 4, 5]);
* Dumper("file.yaml").dump(node);
* --------------------
*
* Write multiple YAML documents to a file:
* --------------------
* auto node1 = Node([1, 2, 3, 4, 5]);
* auto node2 = Node("This document contains only one string");
* Dumper("file.yaml").dump(node1, node2);
*
* //Or with an array:
* //Dumper("file.yaml").dump([node1, node2]);
*
*
* --------------------
*
* Write to memory:
* --------------------
* import std.stream;
* auto stream = new MemoryStream();
* auto node = Node([1, 2, 3, 4, 5]);
* Dumper(stream).dump(node);
* --------------------
*
* Use a custom representer/resolver to support custom data types and/or implicit tags:
* --------------------
* auto node = Node([1, 2, 3, 4, 5]);
* auto representer = new Representer();
* auto resolver = new Resolver();
*
* //Add representer functions / resolver expressions here...
*
* auto dumper = Dumper("file.yaml");
* dumper.representer = representer;
* dumper.resolver = resolver;
* dumper.dump(node);
* --------------------
*/
struct Dumper
{
unittest
{
auto node = Node([1, 2, 3, 4, 5]);
Dumper(new MemoryStream()).dump(node);
}
unittest
{
auto node1 = Node([1, 2, 3, 4, 5]);
auto node2 = Node("This document contains only one string");
Dumper(new MemoryStream()).dump(node1, node2);
}
unittest
{
import std.stream;
auto stream = new MemoryStream();
auto node = Node([1, 2, 3, 4, 5]);
Dumper(stream).dump(node);
}
unittest
{
auto node = Node([1, 2, 3, 4, 5]);
auto representer = new Representer();
auto resolver = new Resolver();
auto dumper = Dumper(new MemoryStream());
dumper.representer = representer;
dumper.resolver = resolver;
dumper.dump(node);
}
private:
///Resolver to resolve tags.
Resolver resolver_;
///Representer to represent data types.
Representer representer_;
///Stream to write to.
Stream stream_;
///Write scalars in canonical form?
bool canonical_;
///Indentation width.
int indent_ = 2;
///Preferred text width.
uint textWidth_ = 80;
///Line break to use.
LineBreak lineBreak_ = LineBreak.Unix;
///Character encoding to use.
Encoding encoding_ = Encoding.UTF_8;
///YAML version string.
string YAMLVersion_ = "1.1";
///Tag directives to use.
TagDirective[] tags_ = null;
///Always write document start?
Flag!"explicitStart" explicitStart_ = No.explicitStart;
///Always write document end?
Flag!"explicitEnd" explicitEnd_ = No.explicitEnd;
///Name of the output file or stream, used in error messages.
string name_ = "<unknown>";
public:
@disable this();
@disable bool opEquals(ref Dumper);
@disable int opCmp(ref Dumper);
/**
* Construct a Dumper writing to a file.
*
* Params: filename = File name to write to.
*
* Throws: YAMLException if the file can not be dumped to (e.g. cannot be opened).
*/
this(string filename) @trusted
{
name_ = filename;
try{this(new File(filename, FileMode.OutNew));}
catch(StreamException e)
{
throw new YAMLException("Unable to open file " ~ filename ~
" for YAML dumping: " ~ e.msg);
}
}
///Construct a Dumper writing to a _stream. This is useful to e.g. write to memory.
this(Stream stream) @safe
{
resolver_ = new Resolver();
representer_ = new Representer();
stream_ = stream;
}
///Destroy the Dumper.
pure @safe nothrow ~this()
{
YAMLVersion_ = null;
}
///Set stream _name. Used in debugging messages.
@property void name(string name) pure @safe nothrow
{
name_ = name;
}
///Specify custom Resolver to use.
@property void resolver(Resolver resolver) @trusted
{
resolver_.destroy();
resolver_ = resolver;
}
///Specify custom Representer to use.
@property void representer(Representer representer) @trusted
{
representer_.destroy();
representer_ = representer;
}
///Write scalars in _canonical form?
@property void canonical(bool canonical) pure @safe nothrow
{
canonical_ = canonical;
}
///Set indentation width. 2 by default. Must not be zero.
@property void indent(uint indent) pure @safe nothrow
in
{
assert(indent != 0, "Can't use zero YAML indent width");
}
body
{
indent_ = indent;
}
///Set preferred text _width.
@property void textWidth(uint width) pure @safe nothrow
{
textWidth_ = width;
}
///Set line break to use. Unix by default.
@property void lineBreak(LineBreak lineBreak) pure @safe nothrow
{
lineBreak_ = lineBreak;
}
///Set character _encoding to use. UTF-8 by default.
@property void encoding(Encoding encoding) pure @safe nothrow
{
encoding_ = encoding;
}
///Always explicitly write document start?
@property void explicitStart(bool explicit) pure @safe nothrow
{
explicitStart_ = explicit ? Yes.explicitStart : No.explicitStart;
}
///Always explicitly write document end?
@property void explicitEnd(bool explicit) pure @safe nothrow
{
explicitEnd_ = explicit ? Yes.explicitEnd : No.explicitEnd;
}
///Specify YAML version string. "1.1" by default.
@property void YAMLVersion(string YAMLVersion) pure @safe nothrow
{
YAMLVersion_ = YAMLVersion;
}
/**
* Specify tag directives.
*
* A tag directive specifies a shorthand notation for specifying _tags.
* Each tag directive associates a handle with a prefix. This allows for
* compact tag notation.
*
* Each handle specified MUST start and end with a '!' character
* (a single character "!" handle is allowed as well).
*
* Only alphanumeric characters, '-', and '__' may be used in handles.
*
* Each prefix MUST not be empty.
*
* The "!!" handle is used for default YAML _tags with prefix
* "tag:yaml.org,2002:". This can be overridden.
*
* Params: tags = Tag directives (keys are handles, values are prefixes).
*
* Example:
* --------------------
* Dumper dumper = Dumper("file.yaml");
* string[string] directives;
* directives["!short!"] = "tag:long.org,2011:";
* //This will emit tags starting with "tag:long.org,2011"
* //with a "!short!" prefix instead.
* dumper.tagDirectives(directives);
* dumper.dump(Node("foo"));
* --------------------
*/
@property void tagDirectives(string[string] tags) pure @trusted
{
TagDirective[] t;
foreach(handle, prefix; tags)
{
assert(handle.length >= 1 && handle[0] == '!' && handle[$ - 1] == '!',
"A tag handle is empty or does not start and end with a "
"'!' character : " ~ handle);
assert(prefix.length >= 1, "A tag prefix is empty");
t ~= TagDirective(handle, prefix);
}
tags_ = t;
}
/**
* Dump one or more YAML _documents to the file/stream.
*
* Note that while you can call dump() multiple times on the same
* dumper, you will end up writing multiple YAML "files" to the same
* file/stream.
*
* Params: documents = Documents to _dump (root nodes of the _documents).
*
* Throws: YAMLException on error (e.g. invalid nodes,
* unable to write to file/stream).
*/
void dump(Node[] documents ...) @trusted
{
try
{
auto emitter = Emitter(stream_, canonical_, indent_, textWidth_, lineBreak_);
auto serializer = Serializer(emitter, resolver_, encoding_, explicitStart_,
explicitEnd_, YAMLVersion_, tags_);
foreach(ref document; documents)
{
representer_.represent(serializer, document);
}
}
catch(YAMLException e)
{
throw new YAMLException("Unable to dump YAML to stream "
~ name_ ~ " : " ~ e.msg);
}
}
package:
/*
* Emit specified events. Used for debugging/testing.
*
* Params: events = Events to emit.
*
* Throws: YAMLException if unable to emit.
*/
void emit(Event[] events) @system
{
try
{
auto emitter = Emitter(stream_, canonical_, indent_, textWidth_, lineBreak_);
foreach(ref event; events)
{
emitter.emit(event);
}
}
catch(YAMLException e)
{
throw new YAMLException("Unable to emit YAML to stream "
~ name_ ~ " : " ~ e.msg);
}
}
}