nix/src/libexpr/value-to-xml.cc

#include "value-to-xml.hh"
#include "xml-writer.hh"
#include "nixexpr-ast.hh"
#include "aterm.hh"
#include "util.hh"

#include <cstdlib>


namespace nix {

    
static XMLAttrs singletonAttrs(const string & name, const string & value)
{
    XMLAttrs attrs;
    attrs[name] = value;
    return attrs;
}


static void printValueAsXML(EvalState & state, bool strict, Value & v,
    XMLWriter & doc, PathSet & context, PathSet & drvsSeen);


static void showAttrs(EvalState & state, bool strict, Bindings & attrs,
    XMLWriter & doc, PathSet & context, PathSet & drvsSeen)
{
    StringSet names;
    foreach (Bindings::iterator, i, attrs)
        names.insert(aterm2String(i->first));
    foreach (StringSet::iterator, i, names) {
        XMLOpenElement _(doc, "attr", singletonAttrs("name", *i));
        printValueAsXML(state, strict, attrs[toATerm(*i)], doc, context, drvsSeen);
    }
}


static void printPatternAsXML(Pattern pat, XMLWriter & doc)
{
    ATerm name;
    ATermList formals;
    ATermBool ellipsis;
    if (matchVarPat(pat, name))
        doc.writeEmptyElement("varpat", singletonAttrs("name", aterm2String(name)));
    else if (matchAttrsPat(pat, formals, ellipsis, name)) {
        XMLAttrs attrs;
        if (name != sNoAlias) attrs["name"] = aterm2String(name);
        if (ellipsis == eTrue) attrs["ellipsis"] = "1";
        XMLOpenElement _(doc, "attrspat", attrs);
        for (ATermIterator i(formals); i; ++i) {
            Expr name; ATerm dummy;
            if (!matchFormal(*i, name, dummy)) abort();
            doc.writeEmptyElement("attr", singletonAttrs("name", aterm2String(name)));
        }
    }
}


static void printValueAsXML(EvalState & state, bool strict, Value & v,
    XMLWriter & doc, PathSet & context, PathSet & drvsSeen)
{
    checkInterrupt();

    if (strict) state.forceValue(v);
        
    switch (v.type) {

        case tInt:
            doc.writeEmptyElement("int", singletonAttrs("value", (format("%1%") % v.integer).str()));
            break;

        case tBool:
            doc.writeEmptyElement("bool", singletonAttrs("value", v.boolean ? "true" : "false"));
            break;

        case tString:
            /* !!! show the context? */
            doc.writeEmptyElement("string", singletonAttrs("value", v.string.s));
            break;

        case tPath:
            doc.writeEmptyElement("path", singletonAttrs("value", v.path));
            break;

        case tNull:
            doc.writeEmptyElement("null");
            break;

        case tAttrs:
            if (state.isDerivation(v)) {
                XMLAttrs xmlAttrs;
            
                Bindings::iterator a = v.attrs->find(toATerm("derivation"));

                Path drvPath;
                a = v.attrs->find(toATerm("drvPath"));
                if (a != v.attrs->end() && a->second.type == tString)
                    xmlAttrs["drvPath"] = drvPath = a->second.string.s;
        
                a = v.attrs->find(toATerm("outPath"));
                if (a != v.attrs->end() && a->second.type == tString)
                    xmlAttrs["outPath"] = a->second.string.s;

                XMLOpenElement _(doc, "derivation", xmlAttrs);

                if (drvPath != "" && drvsSeen.find(drvPath) == drvsSeen.end()) {
                    drvsSeen.insert(drvPath);
                    showAttrs(state, strict, *v.attrs, doc, context, drvsSeen);
                } else
                    doc.writeEmptyElement("repeated");
            }

            else {
                XMLOpenElement _(doc, "attrs");
                showAttrs(state, strict, *v.attrs, doc, context, drvsSeen);
            }
            
            break;

        case tList: {
            XMLOpenElement _(doc, "list");
            for (unsigned int n = 0; n < v.list.length; ++n)
                printValueAsXML(state, strict, v.list.elems[n], doc, context, drvsSeen);
            break;
        }

        case tLambda: {
            XMLOpenElement _(doc, "function");
            printPatternAsXML(v.lambda.pat, doc);
            break;
        }

        default:
            doc.writeEmptyElement("unevaluated");
    }
}


void printValueAsXML(EvalState & state, bool strict,
    Value & v, std::ostream & out, PathSet & context)
{
    XMLWriter doc(true, out);
    XMLOpenElement root(doc, "expr");
    PathSet drvsSeen;    
    printValueAsXML(state, strict, v, doc, context, drvsSeen);
}

 
}