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use crate::format::Formatter;
use anyhow::Error;
use handlebars::{
handlebars_helper, Context, Decorator, Handlebars, Helper, HelperDef, HelperResult, Output,
RenderContext, RenderError, Renderable,
};
use std::collections::HashMap;
use std::path::Path;
type FormatterRef<'a> = &'a (dyn Formatter + Send + Sync);
pub fn expand(file: &Path, formatter: FormatterRef) -> Result<String, Error> {
let mut handlebars = Handlebars::new();
handlebars.set_strict_mode(true);
handlebars.register_helper("lower", Box::new(lower));
handlebars.register_helper("options", Box::new(OptionsHelper { formatter }));
handlebars.register_helper("option", Box::new(OptionHelper { formatter }));
handlebars.register_helper("man", Box::new(ManLinkHelper { formatter }));
handlebars.register_decorator("set", Box::new(set_decorator));
handlebars.register_template_file("template", file)?;
let includes = file.parent().unwrap().join("includes");
handlebars.register_templates_directory(".md", includes)?;
let man_name = file
.file_stem()
.expect("expected filename")
.to_str()
.expect("utf8 filename")
.to_string();
let data = HashMap::from([("man_name", man_name)]);
let expanded = handlebars.render("template", &data)?;
Ok(expanded)
}
struct OptionsHelper<'a> {
formatter: FormatterRef<'a>,
}
impl HelperDef for OptionsHelper<'_> {
fn call<'reg: 'rc, 'rc>(
&self,
h: &Helper<'reg, 'rc>,
r: &'reg Handlebars<'reg>,
ctx: &'rc Context,
rc: &mut RenderContext<'reg, 'rc>,
out: &mut dyn Output,
) -> HelperResult {
if in_options(rc) {
return Err(RenderError::new("options blocks cannot be nested"));
}
set_in_context(rc, "__MDMAN_IN_OPTIONS", serde_json::Value::Bool(true));
let s = self.formatter.render_options_start();
out.write(&s)?;
let t = match h.template() {
Some(t) => t,
None => return Err(RenderError::new("options block must not be empty")),
};
let block = t.renders(r, ctx, rc)?;
out.write(&block)?;
let s = self.formatter.render_options_end();
out.write(&s)?;
remove_from_context(rc, "__MDMAN_IN_OPTIONS");
Ok(())
}
}
fn in_options(rc: &RenderContext<'_, '_>) -> bool {
rc.context()
.map_or(false, |ctx| ctx.data().get("__MDMAN_IN_OPTIONS").is_some())
}
struct OptionHelper<'a> {
formatter: FormatterRef<'a>,
}
impl HelperDef for OptionHelper<'_> {
fn call<'reg: 'rc, 'rc>(
&self,
h: &Helper<'reg, 'rc>,
r: &'reg Handlebars<'reg>,
ctx: &'rc Context,
rc: &mut RenderContext<'reg, 'rc>,
out: &mut dyn Output,
) -> HelperResult {
if !in_options(rc) {
return Err(RenderError::new("option must be in options block"));
}
let params = h.params();
if params.is_empty() {
return Err(RenderError::new(
"option block must have at least one param",
));
}
let params = params
.iter()
.map(|param| {
param
.value()
.as_str()
.ok_or_else(|| RenderError::new("option params must be strings"))
})
.collect::<Result<Vec<&str>, RenderError>>()?;
let t = match h.template() {
Some(t) => t,
None => return Err(RenderError::new("option block must not be empty")),
};
let block = t.renders(r, ctx, rc)?;
let man_name = ctx
.data()
.get("man_name")
.expect("expected man_name in context")
.as_str()
.expect("expect man_name str");
let option = self
.formatter
.render_option(¶ms, &block, man_name)
.map_err(|e| RenderError::new(format!("option render failed: {}", e)))?;
out.write(&option)?;
Ok(())
}
}
struct ManLinkHelper<'a> {
formatter: FormatterRef<'a>,
}
impl HelperDef for ManLinkHelper<'_> {
fn call<'reg: 'rc, 'rc>(
&self,
h: &Helper<'reg, 'rc>,
_r: &'reg Handlebars<'reg>,
_ctx: &'rc Context,
_rc: &mut RenderContext<'reg, 'rc>,
out: &mut dyn Output,
) -> HelperResult {
let params = h.params();
if params.len() != 2 {
return Err(RenderError::new("{{man}} must have two arguments"));
}
let name = params[0]
.value()
.as_str()
.ok_or_else(|| RenderError::new("man link name must be a string"))?;
let section = params[1]
.value()
.as_u64()
.ok_or_else(|| RenderError::new("man link section must be an integer"))?;
let section =
u8::try_from(section).map_err(|_e| RenderError::new("section number too large"))?;
let link = self
.formatter
.linkify_man_to_md(name, section)
.map_err(|e| RenderError::new(format!("failed to linkify man: {}", e)))?;
out.write(&link)?;
Ok(())
}
}
fn set_decorator(
d: &Decorator,
_: &Handlebars,
_ctx: &Context,
rc: &mut RenderContext,
) -> Result<(), RenderError> {
let data_to_set = d.hash();
for (k, v) in data_to_set {
set_in_context(rc, k, v.value().clone());
}
Ok(())
}
fn set_in_context(rc: &mut RenderContext, key: &str, value: serde_json::Value) {
let mut ctx = match rc.context() {
Some(c) => (*c).clone(),
None => Context::wraps(serde_json::Value::Object(serde_json::Map::new())).unwrap(),
};
if let serde_json::Value::Object(m) = ctx.data_mut() {
m.insert(key.to_string(), value);
rc.set_context(ctx);
} else {
panic!("expected object in context");
}
}
fn remove_from_context(rc: &mut RenderContext, key: &str) {
let ctx = rc.context().expect("cannot remove from null context");
let mut ctx = (*ctx).clone();
if let serde_json::Value::Object(m) = ctx.data_mut() {
m.remove(key);
rc.set_context(ctx);
} else {
panic!("expected object in context");
}
}
handlebars_helper!(lower: |s: str| s.to_lowercase());