1fc9ba4885
Value now carries a shared_ptr<Bindings>, and all Bindings constructors return a unique_ptr<Bindings>. The test that wanted to compare two Bindings by putting them into Values has been modified to use the new Equal() method on Bindings (extracted from EvalState). Change-Id: I8dfb60e65fdabb717e3b3e5d56d5b3fc82f70883 Reviewed-on: https://cl.tvl.fyi/c/depot/+/1744 Tested-by: BuildkiteCI Reviewed-by: glittershark <grfn@gws.fyi> Reviewed-by: tazjin <mail@tazj.in>
109 lines
2.8 KiB
C++
109 lines
2.8 KiB
C++
#include "libexpr/attr-path.hh"
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#include <absl/strings/numbers.h>
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#include "libexpr/eval-inline.hh"
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#include "libutil/util.hh"
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namespace nix {
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static Strings parseAttrPath(const std::string& s) {
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Strings res;
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std::string cur;
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std::string::const_iterator i = s.begin();
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while (i != s.end()) {
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if (*i == '.') {
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res.push_back(cur);
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cur.clear();
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} else if (*i == '"') {
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++i;
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while (true) {
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if (i == s.end()) {
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throw Error(format("missing closing quote in selection path '%1%'") %
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s);
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}
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if (*i == '"') {
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break;
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}
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cur.push_back(*i++);
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}
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} else {
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cur.push_back(*i);
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}
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++i;
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}
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if (!cur.empty()) {
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res.push_back(cur);
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}
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return res;
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}
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Value* findAlongAttrPath(EvalState& state, const std::string& attrPath,
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Bindings* autoArgs, Value& vIn) {
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Strings tokens = parseAttrPath(attrPath);
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Error attrError =
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Error(format("attribute selection path '%1%' does not match expression") %
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attrPath);
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Value* v = &vIn;
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for (auto& attr : tokens) {
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/* Is i an index (integer) or a normal attribute name? */
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enum { apAttr, apIndex } apType = apAttr;
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unsigned int attrIndex;
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if (absl::SimpleAtoi(attr, &attrIndex)) {
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apType = apIndex;
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}
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/* Evaluate the expression. */
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Value* vNew = state.allocValue();
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state.autoCallFunction(autoArgs, *v, *vNew);
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v = vNew;
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state.forceValue(*v);
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/* It should evaluate to either a set or an expression,
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according to what is specified in the attrPath. */
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if (apType == apAttr) {
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if (v->type != tAttrs) {
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throw TypeError(format("the expression selected by the selection path "
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"'%1%' should be a set but is %2%") %
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attrPath % showType(*v));
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}
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if (attr.empty()) {
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throw Error(format("empty attribute name in selection path '%1%'") %
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attrPath);
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}
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Bindings::iterator a = v->attrs->find(state.symbols.Create(attr));
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if (a == v->attrs->end()) {
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throw Error(
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format("attribute '%1%' in selection path '%2%' not found") % attr %
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attrPath);
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}
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v = &*(a->second).value;
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}
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else if (apType == apIndex) {
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if (!v->isList()) {
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throw TypeError(format("the expression selected by the selection path "
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"'%1%' should be a list but is %2%") %
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attrPath % showType(*v));
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}
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if (attrIndex >= v->listSize()) {
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throw Error(
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format("list index %1% in selection path '%2%' is out of range") %
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attrIndex % attrPath);
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}
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v = (*v->list)[attrIndex];
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}
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}
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return v;
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}
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} // namespace nix
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