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/*! ## An XSLT compiler
Compile an XSLT stylesheet into a [Transform]ation.
Once the stylesheet has been compiled, it may then be evaluated with an appropriate context.
NB. This module, by default, does not resolve include or import statements. See the xrust-net crate for a helper module to do that.
```rust
use std::rc::Rc;
use xrust::xdmerror::Error;
use xrust::qname::QualifiedName;
use xrust::item::{Item, Node, NodeType, Sequence, SequenceTrait};
use xrust::transform::Transform;
use xrust::transform::context::StaticContext;
use xrust::trees::intmuttree::{Document, RNode, NodeBuilder};
use xrust::xslt::from_document;
// This is for the callback in the static context
type F = Box<dyn FnMut(&str) -> Result<(), Error>>;
// A little helper function that wraps the toplevel node in a Document
fn make_from_str(s: &str) -> Result<RNode, Error> {
let e = Document::try_from((s, None, None)).expect("failed to parse XML").content[0].clone();
let mut d = NodeBuilder::new(NodeType::Document).build();
d.push(e).expect("unable to append node");
Ok(d)
}
// The source document (a tree)
let src = Rc::new(Item::Node(
make_from_str("<Example><Title>XSLT in Rust</Title><Paragraph>A simple document.</Paragraph></Example>")
.expect("unable to parse XML")
));
// The XSL stylesheet
let style = make_from_str("<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform'>
<xsl:template match='child::Example'><html><xsl:apply-templates/></html></xsl:template>
<xsl:template match='child::Title'><head><title><xsl:apply-templates/></title></head></xsl:template>
<xsl:template match='child::Paragraph'><body><p><xsl:apply-templates/></p></body></xsl:template>
</xsl:stylesheet>")
.expect("unable to parse stylesheet");
// Compile the stylesheet
let mut ctxt = from_document(
style,
None,
make_from_str,
|_| Ok(String::new())
).expect("failed to compile stylesheet");
// Set the source document as the context item
ctxt.context(vec![src], 0);
// Make an empty result document
ctxt.result_document(NodeBuilder::new(NodeType::Document).build());
// Let 'er rip!
// Evaluate the transformation
let seq = ctxt.evaluate(&mut StaticContext::<F>::new())
.expect("evaluation failed");
// Serialise the sequence as XML
assert_eq!(seq.to_xml(), "<html><head><title>XSLT in Rust</title></head><body><p>A simple document.</p></body></html>")
*/
use std::rc::Rc;
use crate::item::{Item, Node, NodeType, Sequence};
use crate::output::*;
use crate::parser::avt::parse as parse_avt;
use crate::parser::xpath::parse;
use crate::pattern::Pattern;
use crate::qname::*;
use crate::transform::context::{Context, ContextBuilder};
use crate::transform::template::Template;
use crate::transform::{
Axis, Grouping, KindTest, NameTest, NodeMatch, NodeTest, Transform, WildcardOrName,
};
use crate::value::*;
use crate::xdmerror::*;
use std::convert::TryFrom;
use url::Url;
const XSLTNS: &str = "http://www.w3.org/1999/XSL/Transform";
/// The XSLT trait allows an object to use an XSL Stylesheet to transform a document into a [Sequence].
pub trait XSLT: Node {
/// Interpret the object as an XSL Stylesheet and transform a source document.
/// The [Node] that is given as the source document becomes the initial context for the transformation.
fn transform<N: Node, F, G>(
&self,
src: Rc<Item<N>>,
b: Option<Url>,
f: F,
g: G,
) -> Result<Sequence<N>, Error>
where
F: Fn(&str) -> Result<N, Error>,
G: Fn(&Url) -> Result<String, Error>;
// {
// let sc = from_document(self.clone(), b, f, g)?;
// let ctxt = ContextBuilder::from(&sc)
// .current(vec![src])
// .build();
// ctxt.evaluate()
// }
}
/// Compiles a [Node] into a transformation [Context].
/// NB. Due to whitespace stripping, this is destructive of the stylesheet.
/// The argument f is a closure that parses a string to a [Node].
/// The argument g is a closure that resolves a URL to a string.
/// These are used for include and import modules.
/// They are not included in this module since some environments, in particular Wasm, do not have I/O facilities.
pub fn from_document<N: Node, F, G>(
styledoc: N,
base: Option<Url>,
f: F,
g: G,
) -> Result<Context<N>, Error>
where
F: Fn(&str) -> Result<N, Error>,
G: Fn(&Url) -> Result<String, Error>,
{
// Check that this is a valid XSLT stylesheet
// There must be a single element as a child of the root node, and it must be named xsl:stylesheet or xsl:transform
let mut rnit = styledoc.child_iter();
let stylenode = match rnit.next() {
Some(root) => {
if !(root.name().get_nsuri_ref() == Some(XSLTNS)
&& (root.name().get_localname() == "stylesheet"
|| root.name().get_localname() == "transform"))
{
return Result::Err(Error::new(
ErrorKind::TypeError,
String::from("not an XSLT stylesheet"),
));
} else {
root
}
}
None => {
return Result::Err(Error::new(
ErrorKind::TypeError,
String::from("document does not have document element"),
))
}
};
if rnit.next().is_some() {
return Result::Err(Error::new(
ErrorKind::TypeError,
String::from("extra element: not an XSLT stylesheet"),
));
}
// TODO: check version attribute
// Strip whitespace from the stylesheet
strip_whitespace(
styledoc.clone(),
true,
&vec![NodeTest::Name(NameTest {
ns: None,
prefix: None,
name: Some(WildcardOrName::Wildcard),
})],
&vec![NodeTest::Name(NameTest {
ns: Some(WildcardOrName::Name(XSLTNS.to_string())),
prefix: Some("xsl".to_string()),
name: Some(WildcardOrName::Name("text".to_string())),
})],
)?;
// Setup the serialization of the primary result document
let mut od = OutputDefinition::new();
if let Some(c) = stylenode.child_iter().find(|c| {
!(c.is_element()
&& c.name().get_nsuri_ref() == Some(XSLTNS)
&& c.name().get_localname() == "output")
}) {
let b: bool = matches!(
c.get_attribute(&QualifiedName::new(None, None, "indent".to_string()))
.to_string()
.as_str(),
"yes" | "true" | "1"
);
od.set_indent(b);
};
// Iterate over children, looking for includes
// * resolve href
// * fetch document
// * parse XML
// * replace xsl:include element with content
stylenode
.child_iter()
.filter(|c| {
c.is_element()
&& c.name().get_nsuri_ref() == Some(XSLTNS)
&& c.name().get_localname() == "include"
})
.try_for_each(|mut c| {
let h = c.get_attribute(&QualifiedName::new(None, None, "href".to_string()));
let url = match base.clone().map_or_else(
|| Url::parse(h.to_string().as_str()),
|full| full.join(h.to_string().as_str()),
) {
Ok(u) => u,
Err(_) => {
return Result::Err(Error::new(
ErrorKind::Unknown,
format!(
"unable to parse href URL \"{}\" baseurl \"{}\"",
h,
base.clone()
.map_or(String::from("--no base--"), |b| b.to_string())
),
));
}
};
let xml = g(&url)?;
let module = f(xml.as_str().trim())?;
// TODO: check that the module is a valid XSLT stylesheet, etc
// Copy each top-level element of the module to the main stylesheet,
// inserting before the xsl:include node
let moddoc = module.first_child().unwrap();
moddoc.child_iter().try_for_each(|mc| {
c.insert_before(mc)?;
Ok::<(), Error>(())
})?;
// Remove the xsl:include element node
c.pop()?;
Ok(())
})?;
// Iterate over children, looking for imports
// * resolve href
// * fetch document
// * parse XML
// * replace xsl:import element with content
stylenode
.child_iter()
.filter(|c| {
c.is_element()
&& c.name().get_nsuri_ref() == Some(XSLTNS)
&& c.name().get_localname() == "import"
})
.try_for_each(|mut c| {
let h = c.get_attribute(&QualifiedName::new(None, None, "href".to_string()));
let url = match base.clone().map_or_else(
|| Url::parse(h.to_string().as_str()),
|full| full.join(h.to_string().as_str()),
) {
Ok(u) => u,
Err(_) => {
return Result::Err(Error::new(
ErrorKind::Unknown,
format!(
"unable to parse href URL \"{}\" baseurl \"{}\"",
h,
base.clone()
.map_or(String::from("--no base--"), |b| b.to_string())
),
));
}
};
let xml = g(&url)?;
let module = f(xml.as_str().trim())?;
// TODO: check that the module is a valid XSLT stylesheet, etc
// Copy each top-level element of the module to the main stylesheet,
// inserting before the xsl:include node
// TODO: Don't Panic
let moddoc = module.first_child().unwrap();
moddoc.child_iter().try_for_each(|mc| {
if mc.node_type() == NodeType::Element {
// Add the import precedence attribute
let newnode = mc.deep_copy()?;
let newat = styledoc.new_attribute(
QualifiedName::new(
Some(String::from("http://github.com/ballsteve/xrust")),
None,
String::from("import"),
),
Value::from(1),
)?;
newnode.add_attribute(newat)?;
c.insert_before(newnode)?;
} else {
let newnode = mc.deep_copy()?;
c.insert_before(newnode)?;
}
Ok::<(), Error>(())
})?;
// Remove the xsl:import element node
c.pop()?;
Ok::<(), Error>(())
})?;
// Iterate over children, looking for templates
// * compile match pattern
// * compile content into sequence constructor
// * register template in dynamic context
let mut templates: Vec<Template<N>> = vec![];
stylenode
.child_iter()
.filter(|c| {
c.is_element()
&& c.name().get_nsuri_ref() == Some(XSLTNS)
&& c.name().get_localname() == "template"
})
.try_for_each(|c| {
let m = c.get_attribute(&QualifiedName::new(None, None, "match".to_string()));
let pat = Pattern::try_from(m.to_string())?;
let mut body = vec![];
c.child_iter().try_for_each(|d| {
body.push(to_transform(d)?);
Ok::<(), Error>(())
})?;
//sc.static_analysis(&mut pat);
//sc.static_analysis(&mut body);
// Determine the priority of the template
let pr = c.get_attribute(&QualifiedName::new(None, None, "priority".to_string()));
let prio: f64 = match pr.to_string().as_str() {
"" => {
// Calculate the default priority
// TODO: more work to be done interpreting XSLT 6.5
match &pat {
Pattern::Predicate(p) => match p {
Transform::Empty => -1.0,
_ => 1.0,
},
Pattern::Selection(s) => {
let ((t, nt), q) = s.clone().t.unwrap();
// If "/" then -0.5
match (t, nt) {
(Axis::SelfAttribute, _) => -0.5,
(Axis::SelfAxis, Axis::Parent)
| (Axis::SelfAxis, Axis::Ancestor)
| (Axis::SelfAxis, Axis::AncestorOrSelf) => match q {
NodeTest::Name(nm) => match nm.name {
Some(WildcardOrName::Wildcard) => -0.5,
Some(_) => 0.0,
_ => -0.5,
},
NodeTest::Kind(_kt) => -0.5,
},
_ => 0.5,
}
}
_ => -1.0,
}
}
_ => pr.to_string().parse::<f64>().unwrap(), // TODO: better error handling
};
// Set the import precedence
let mut import: usize = 0;
let im = c.get_attribute(&QualifiedName::new(
Some(String::from("http://github.com/ballsteve/xrust")),
None,
String::from("import"),
));
if im.to_string() != "" {
import = im.to_int()? as usize
}
templates.push(Template::new(
pat,
Transform::SequenceItems(body),
Some(prio),
vec![import],
None,
None,
));
Ok::<(), Error>(())
})?;
Ok(ContextBuilder::new()
// Define the builtin templates
// See XSLT 6.7. This implements text-only-copy.
// TODO: Support deep-copy, shallow-copy, deep-skin, shallow-skip and fail
// This matches "/" and processes the root element
.template(Template::new(
Pattern::try_from("/")?,
Transform::ApplyTemplates(Box::new(Transform::Step(NodeMatch::new(
Axis::Child,
NodeTest::Kind(KindTest::Any),
)))),
None,
vec![0],
None,
None,
))
// This matches "*" and applies templates to all children
.template(Template::new(
Pattern::try_from("child::*")?,
Transform::ApplyTemplates(Box::new(Transform::Step(NodeMatch::new(
Axis::Child,
NodeTest::Kind(KindTest::Any),
)))),
None,
vec![0],
None,
None,
))
// This matches "text()" and copies content
.template(Template::new(
Pattern::try_from("child::text()")?,
Transform::ContextItem,
None,
vec![0],
None,
None,
))
.template_all(templates)
.output_definition(od)
.build())
}
/// Compile a node in a template to a sequence [Combinator]
fn to_transform<N: Node>(n: N) -> Result<Transform<N>, Error> {
match n.node_type() {
NodeType::Text => Ok(Transform::Literal(Rc::new(Item::Value(Value::String(
n.to_string(),
))))),
NodeType::Element => {
match (n.name().get_nsuri_ref(), n.name().get_localname().as_str()) {
(Some(XSLTNS), "text") => {
let doe = n.get_attribute(&QualifiedName::new(
None,
None,
"disable-output-escaping".to_string(),
));
if !doe.to_string().is_empty() {
match &doe.to_string()[..] {
"yes" => Ok(Transform::Literal(Rc::new(Item::Value(Value::String(
n.to_string(),
))))),
"no" => {
let text = n
.to_string()
.replace('&', "&")
.replace('>', ">")
.replace('<', "<")
.replace('\'', "'")
.replace('\"', """);
Ok(Transform::Literal(Rc::new(Item::Value(Value::from(text)))))
}
_ => Result::Err(Error::new(
ErrorKind::TypeError,
"disable-output-escaping only accepts values yes or no."
.to_string(),
)),
}
} else {
let text = n
.to_string()
.replace('&', "&")
.replace('>', ">")
.replace('<', "<")
.replace('\'', "'")
.replace('\"', """);
Ok(Transform::Literal(Rc::new(Item::Value(Value::from(text)))))
}
}
(Some(XSLTNS), "apply-templates") => {
let sel =
n.get_attribute(&QualifiedName::new(None, None, "select".to_string()));
if !sel.to_string().is_empty() {
Ok(Transform::ApplyTemplates(Box::new(parse::<N>(
&sel.to_string(),
)?)))
} else {
// If there is no select attribute, then default is "child::node()"
Ok(Transform::ApplyTemplates(Box::new(Transform::Step(
NodeMatch::new(Axis::Child, NodeTest::Kind(KindTest::Any)),
))))
}
}
(Some(XSLTNS), "apply-imports") => Ok(Transform::ApplyImports),
(Some(XSLTNS), "sequence") => {
let s = n.get_attribute(&QualifiedName::new(None, None, "select".to_string()));
if !s.to_string().is_empty() {
Ok(parse::<N>(&s.to_string())?)
} else {
Result::Err(Error::new(
ErrorKind::TypeError,
"missing select attribute".to_string(),
))
}
}
(Some(XSLTNS), "if") => {
let t = n.get_attribute(&QualifiedName::new(None, None, "test".to_string()));
if !t.to_string().is_empty() {
Ok(Transform::Switch(
vec![(
parse::<N>(&t.to_string())?,
Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?),
)],
Box::new(Transform::Empty),
))
} else {
Result::Err(Error::new(
ErrorKind::TypeError,
"missing test attribute".to_string(),
))
}
}
(Some(XSLTNS), "choose") => {
let mut clauses: Vec<(Transform<N>, Transform<N>)> = Vec::new();
let mut otherwise: Option<Transform<N>> = None;
let mut status: Option<Error> = None;
n.child_iter()
.try_for_each(|m| {
// look for when elements
// then find an otherwise
// fail on anything else (apart from whitespace, comments, PIs)
match m.node_type() {
NodeType::Element => {
match (m.name().get_nsuri_ref(), m.name().get_localname().as_str()) {
(Some(XSLTNS), "when") => {
if otherwise.is_none() {
let t = m.get_attribute(&QualifiedName::new(None, None, "test".to_string()));
if !t.to_string().is_empty() {
clauses.push((
parse::<N>(&t.to_string())?,
Transform::SequenceItems(
m.child_iter()
.try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?
)
));
} else {
status.replace(Error::new(ErrorKind::TypeError, "missing test attribute".to_string()));
}
} else {
status.replace(Error::new(ErrorKind::TypeError, "invalid content in choose element: when follows otherwise".to_string()));
}
}
(Some(XSLTNS), "otherwise") => {
if !clauses.is_empty() {
otherwise = Some(Transform::SequenceItems(m.child_iter()
.try_fold(
vec![],
|mut o, e| {
o.push(to_transform(e)?);
Ok(o)
},
)?));
} else {
status.replace(Error::new(ErrorKind::TypeError, "invalid content in choose element: no when elements".to_string()));
}
}
_ => {
status.replace(Error::new(ErrorKind::TypeError, "invalid element content in choose element".to_string()));
}
}
}
NodeType::Text => {
if !n.to_string().trim().is_empty() {
status.replace(Error::new(ErrorKind::TypeError, "invalid text content in choose element".to_string()));
}
}
NodeType::Comment |
NodeType::ProcessingInstruction => {}
_ => {
status.replace(Error::new(ErrorKind::TypeError, "invalid content in choose element".to_string()));
}
}
Ok::<(), Error>(())
})?;
match status {
Some(e) => Result::Err(e),
None => Ok(Transform::Switch(
clauses,
otherwise.map_or(Box::new(Transform::Empty), |o| Box::new(o)),
)),
}
}
(Some(XSLTNS), "for-each") => {
let s = n.get_attribute(&QualifiedName::new(None, None, "select".to_string()));
if !s.to_string().is_empty() {
Ok(Transform::ForEach(
None,
Box::new(parse::<N>(&s.to_string())?),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
))
} else {
Result::Err(Error::new(
ErrorKind::TypeError,
"missing select attribute".to_string(),
))
}
}
(Some(XSLTNS), "for-each-group") => {
let s = n.get_attribute(&QualifiedName::new(None, None, "select".to_string()));
if !s.to_string().is_empty() {
match (
n.get_attribute(&QualifiedName::new(
None,
None,
"group-by".to_string(),
))
.to_string()
.as_str(),
n.get_attribute(&QualifiedName::new(
None,
None,
"group-adjacent".to_string(),
))
.to_string()
.as_str(),
n.get_attribute(&QualifiedName::new(
None,
None,
"group-starting-with".to_string(),
))
.to_string()
.as_str(),
n.get_attribute(&QualifiedName::new(
None,
None,
"group-ending-with".to_string(),
))
.to_string()
.as_str(),
) {
(by, "", "", "") => Ok(Transform::ForEach(
Some(Grouping::By(vec![parse::<N>(by)?])),
Box::new(parse::<N>(&s.to_string())?),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
)),
("", adj, "", "") => Ok(Transform::ForEach(
Some(Grouping::Adjacent(vec![parse::<N>(adj)?])),
Box::new(parse::<N>(&s.to_string())?),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
)),
// TODO: group-starting-with and group-ending-with
_ => Result::Err(Error::new(
ErrorKind::NotImplemented,
"invalid grouping attribute(s) specified".to_string(),
)),
}
} else {
Result::Err(Error::new(
ErrorKind::TypeError,
"missing select attribute".to_string(),
))
}
}
(Some(XSLTNS), "copy") => {
// TODO: handle select attribute
let content: Vec<Transform<N>> =
n.child_iter().try_fold(vec![], |mut body, e| {
body.push(to_transform(e)?);
Ok(body)
})?;
Ok(Transform::Copy(
Box::new(Transform::ContextItem), // TODO: this is where the select attribute would go
// The content of this element is a template for the content of the new item
Box::new(if content.is_empty() {
Transform::Empty
} else {
Transform::SequenceItems(content)
}),
))
}
(Some(XSLTNS), "copy-of") => {
let s = n.get_attribute(&QualifiedName::new(None, None, "select".to_string()));
if !s.to_string().is_empty() {
Ok(Transform::DeepCopy(Box::new(parse::<N>(&s.to_string())?)))
} else {
Ok(Transform::DeepCopy(Box::new(Transform::ContextItem)))
}
}
(Some(XSLTNS), "element") => {
let m = n.get_attribute(&QualifiedName::new(None, None, "name".to_string()));
if m.to_string().is_empty() {
return Result::Err(Error::new(
ErrorKind::TypeError,
"missing name attribute".to_string(),
));
}
Ok(Transform::Element(
Box::new(parse_avt(m.to_string().as_str())?),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
))
}
(Some(XSLTNS), "attribute") => {
let m = n.get_attribute(&QualifiedName::new(None, None, "name".to_string()));
if !m.to_string().is_empty() {
Ok(Transform::LiteralAttribute(
QualifiedName::new(None, None, m.to_string()),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
))
} else {
Result::Err(Error::new(
ErrorKind::TypeError,
"missing name attribute".to_string(),
))
}
}
(Some(XSLTNS), "comment") => Ok(Transform::LiteralComment(Box::new(
Transform::SequenceItems(n.child_iter().try_fold(vec![], |mut body, e| {
body.push(to_transform(e)?);
Ok(body)
})?),
))),
(Some(XSLTNS), "processing-instruction") => {
let m = n.get_attribute(&QualifiedName::new(None, None, "name".to_string()));
if m.to_string().is_empty() {
return Result::Err(Error::new(
ErrorKind::TypeError,
"missing name attribute".to_string(),
));
}
Ok(Transform::LiteralProcessingInstruction(
Box::new(parse_avt(m.to_string().as_str())?),
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
))
}
(Some(XSLTNS), "message") => {
let t =
n.get_attribute(&QualifiedName::new(None, None, "terminate".to_string()));
Ok(Transform::Message(
Box::new(Transform::SequenceItems(n.child_iter().try_fold(
vec![],
|mut body, e| {
body.push(to_transform(e)?);
Ok(body)
},
)?)),
None,
Box::new(Transform::Empty),
Box::new(if t.to_string().is_empty() {
Transform::False
} else {
Transform::Literal(Rc::new(Item::Value(Value::from(t.to_string()))))
}),
))
}
(Some(XSLTNS), u) => Ok(Transform::NotImplemented(format!(
"unsupported XSL element \"{}\"",
u
))),
(u, a) => {
let mut content = vec![];
n.attribute_iter().try_for_each(|e| {
content.push(to_transform(e)?);
Ok::<(), Error>(())
})?;
n.child_iter().try_for_each(|e| {
content.push(to_transform(e)?);
Ok::<(), Error>(())
})?;
Ok(Transform::LiteralElement(
QualifiedName::new(
u.map(|v| v.to_string()),
n.name().get_prefix(),
a.to_string(),
),
Box::new(Transform::SequenceItems(content)),
))
}
}
}
NodeType::Attribute => {
// Get value as a Value
Ok(Transform::LiteralAttribute(
n.name(),
Box::new(Transform::Literal(Rc::new(Item::Value(Value::String(
n.to_string(),
))))),
))
}
_ => {
// TODO: literal elements, etc, pretty much everything in the XSLT spec
println!("found a strange element");
Ok(Transform::NotImplemented(
"other template content".to_string(),
))
}
}
}
/// Strip whitespace nodes from a XDM tree.
/// See [XSLT 4.3](https://www.w3.org/TR/2017/REC-xslt-30-20170608/#stylesheet-stripping).
/// The [Node] argument must be the document node of the tree.
pub fn strip_whitespace<N: Node>(
t: N,
cpi: bool, // strip comments and PIs?
strip: &Vec<NodeTest>,
preserve: &Vec<NodeTest>,
) -> Result<(), Error> {
t.child_iter().try_for_each(|n| {
strip_whitespace_node(n, cpi, strip, preserve, true)?;
Ok(())
})?;
Ok(())
}
/// Strip whitespace nodes from a XDM tree.
/// This function operates under the direction of the xsl:strip-space and xsl:preserve-space directives in a XSLT stylesheet.
pub fn strip_source_document<N: Node>(src: N, style: N) -> Result<(), Error> {
// Find strip-space element, if any, and use it to construct a vector of NodeTests.
// Ditto for preserve-space.
let mut ss: Vec<NodeTest> = vec![];
let mut ps: Vec<NodeTest> = vec![];
style.child_iter().try_for_each(|n| {
// n should be the xsl:stylesheet element
n.child_iter().try_for_each(|m| {
match (
m.node_type(),
m.name().get_nsuri_ref(),
m.name().get_localname().as_str(),
) {
(NodeType::Element, Some(XSLTNS), "strip-space") => {
let v =
m.get_attribute(&QualifiedName::new(None, None, "elements".to_string()));
if !v.to_string().is_empty() {
v.to_string().split_whitespace().try_for_each(|t| {
ss.push(NodeTest::try_from(t)?);
Ok::<(), Error>(())
})?
} else {
return Result::Err(Error::new(
ErrorKind::Unknown,
String::from("missing elements attribute"),
));
}
}
(NodeType::Element, Some(XSLTNS), "preserve-space") => {
let v =
m.get_attribute(&QualifiedName::new(None, None, "elements".to_string()));
if !v.to_string().is_empty() {
v.to_string().split_whitespace().try_for_each(|t| {
ps.push(NodeTest::try_from(t)?);
Ok::<(), Error>(())
})?
} else {
return Result::Err(Error::new(
ErrorKind::Unknown,
String::from("missing elements attribute"),
));
}
}
_ => {}
}
Ok::<(), Error>(())
})?;
Ok::<(), Error>(())
})?;
strip_whitespace(src, false, &ss, &ps)
}
// TODO: the rules for stripping/preserving are a lot more complex
// TODO: Return Result so that errors can be propagated
fn strip_whitespace_node<N: Node>(
mut n: N,
cpi: bool, // strip comments and PIs?
strip: &Vec<NodeTest>,
preserve: &Vec<NodeTest>,
keep: bool,
) -> Result<(), Error> {
match n.node_type() {
NodeType::Comment | NodeType::ProcessingInstruction => {
if cpi {
n.pop()?;
// TODO: Merge text nodes that are now adjacent
}
}
NodeType::Element => {
// Determine if this element toggles the strip/preserve setting
// Match a strip NodeTest or a preserve NodeTest
// The 'strength' of the match determines which setting wins
let mut ss = -1.0;
let mut ps = -1.0;
strip.iter().for_each(|t| match t {
NodeTest::Kind(KindTest::Any) | NodeTest::Kind(KindTest::Element) => ss = -0.5,
NodeTest::Name(nt) => match (nt.ns.as_ref(), nt.name.as_ref()) {
(None, Some(WildcardOrName::Wildcard)) => {
ss = -0.25;
}
(None, Some(WildcardOrName::Name(name))) => {
match (n.name().get_nsuri(), n.name().get_localname()) {
(Some(_), _) => {}
(None, ename) => {
if *name == ename {
ss = 0.5;
}
}
}
}
(Some(WildcardOrName::Name(ns)), Some(WildcardOrName::Name(name))) => {
match (n.name().get_nsuri(), n.name().get_localname()) {
(Some(ens), ename) => {
if *ns == ens && *name == ename {
ss = 0.5;
}
}
(None, ename) => {
if *name == ename {
ss = 0.5;
}
}
}
}
(Some(WildcardOrName::Wildcard), Some(WildcardOrName::Name(_))) => {
ss = -0.25;
}
(Some(WildcardOrName::Name(_)), Some(WildcardOrName::Wildcard)) => {
ss = -0.25;
}
(Some(WildcardOrName::Wildcard), Some(WildcardOrName::Wildcard)) => {
ss = -0.5;
}
_ => {}
},
_ => {}
});
preserve.iter().for_each(|t| match t {
NodeTest::Kind(KindTest::Any) | NodeTest::Kind(KindTest::Element) => ps = -0.5,
NodeTest::Name(nt) => match (nt.ns.as_ref(), nt.name.as_ref()) {
(None, Some(WildcardOrName::Name(name))) => {
match (n.name().get_nsuri(), n.name().get_localname()) {
(Some(_), _) => {}
(None, ename) => {
if *name == ename {
ps = 0.5;
}
}
}
}
(Some(WildcardOrName::Name(ns)), Some(WildcardOrName::Name(name))) => {
match (n.name().get_nsuri(), n.name().get_localname()) {
(Some(ens), ename) => {
if *ns == ens && *name == ename {
ps = 0.5;
}
}
(None, ename) => {
if *name == ename {
ps = 0.5;
}
}
}
}
(Some(WildcardOrName::Wildcard), Some(WildcardOrName::Name(_))) => {
ps = -0.25;
}
(Some(WildcardOrName::Name(_)), Some(WildcardOrName::Wildcard)) => {
ps = -0.25;
}
(Some(WildcardOrName::Wildcard), Some(WildcardOrName::Wildcard)) => {
ps = -0.5;
}
_ => {}
},
_ => {}
});
n.child_iter().try_for_each(|m| {
strip_whitespace_node(
m,
cpi,
strip,
preserve,
if ss > -1.0 {
ps >= ss
} else if ps > -1.0 {
true
} else {
keep
},
)
})?
}
NodeType::Text => {
if n.to_string().trim().is_empty() && !keep {
n.pop()?;
}
}
_ => {}
}
Ok(())
}