1 files changed, 140 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/parser.cc b/third_party/nix/src/libexpr/parser.cc
index 50b7cc3ff8e3..a96d345cc126 100644
--- a/third_party/nix/src/libexpr/parser.cc
+++ b/third_party/nix/src/libexpr/parser.cc
@@ -1,5 +1,14 @@
 #include "libexpr/parser.hh"
 
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "libexpr/eval.hh"
+#include "libstore/download.hh"
+#include "libstore/store-api.hh"
+
 namespace nix {
 
 void addAttr(ExprAttrs* attrs, AttrPath& attrPath, Expr* e, const Pos& pos) {
@@ -182,5 +191,136 @@ Expr* stripIndentation(const Pos& pos, SymbolTable& symbols,
              : new ExprConcatStrings(pos, true, es2);
 }
 
+Path resolveExprPath(Path path) {
+  assert(path[0] == '/');
+
+  /* If `path' is a symlink, follow it.  This is so that relative
+     path references work. */
+  struct stat st;
+  while (true) {
+    if (lstat(path.c_str(), &st))
+      throw SysError(format("getting status of '%1%'") % path);
+    if (!S_ISLNK(st.st_mode)) {
+      break;
+    }
+    path = absPath(readLink(path), dirOf(path));
+  }
+
+  /* If `path' refers to a directory, append `/default.nix'. */
+  if (S_ISDIR(st.st_mode)) path = canonPath(path + "/default.nix");
+
+  return path;
+}
+
+// These methods are actually declared in eval.hh, and were - for some
+// reason - previously implemented in parser.y.
+
+Expr* EvalState::parseExprFromFile(const Path& path) {
+  return parseExprFromFile(path, staticBaseEnv);
+}
+
+Expr* EvalState::parseExprFromFile(const Path& path, StaticEnv& staticEnv) {
+  return parse(readFile(path).c_str(), path, dirOf(path), staticEnv);
+}
+
+Expr* EvalState::parseExprFromString(const std::string& s, const Path& basePath,
+                                     StaticEnv& staticEnv) {
+  return parse(s.c_str(), "(std::string)", basePath, staticEnv);
+}
+
+Expr* EvalState::parseExprFromString(const std::string& s,
+                                     const Path& basePath) {
+  return parseExprFromString(s, basePath, staticBaseEnv);
+}
+
+Expr* EvalState::parseStdin() {
+  // Activity act(*logger, lvlTalkative, format("parsing standard input"));
+  return parseExprFromString(drainFD(0), absPath("."));
+}
+
+void EvalState::addToSearchPath(const std::string& s) {
+  size_t pos = s.find('=');
+  std::string prefix;
+  Path path;
+  if (pos == std::string::npos) {
+    path = s;
+  } else {
+    prefix = std::string(s, 0, pos);
+    path = std::string(s, pos + 1);
+  }
+
+  searchPath.emplace_back(prefix, path);
+}
+
+Path EvalState::findFile(const std::string& path) {
+  return findFile(searchPath, path);
+}
+
+Path EvalState::findFile(SearchPath& searchPath, const std::string& path,
+                         const Pos& pos) {
+  for (auto& i : searchPath) {
+    std::string suffix;
+    if (i.first.empty())
+      suffix = "/" + path;
+    else {
+      auto s = i.first.size();
+      if (path.compare(0, s, i.first) != 0 ||
+          (path.size() > s && path[s] != '/'))
+        continue;
+      suffix = path.size() == s ? "" : "/" + std::string(path, s);
+    }
+    auto r = resolveSearchPathElem(i);
+    if (!r.first) {
+      continue;
+    }
+    Path res = r.second + suffix;
+    if (pathExists(res)) {
+      return canonPath(res);
+    }
+  }
+  format f = format(
+      "file '%1%' was not found in the Nix search path (add it using $NIX_PATH "
+      "or -I)" +
+      std::string(pos ? ", at %2%" : ""));
+  f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
+  throw ThrownError(f % path % pos);
+}
+
+std::pair<bool, std::string> EvalState::resolveSearchPathElem(
+    const SearchPathElem& elem) {
+  auto i = searchPathResolved.find(elem.second);
+  if (i != searchPathResolved.end()) {
+    return i->second;
+  }
+
+  std::pair<bool, std::string> res;
+
+  if (isUri(elem.second)) {
+    try {
+      CachedDownloadRequest request(elem.second);
+      request.unpack = true;
+      res = {true, getDownloader()->downloadCached(store, request).path};
+    } catch (DownloadError& e) {
+      LOG(WARNING) << "Nix search path entry '" << elem.second
+                   << "' cannot be downloaded, ignoring";
+      res = {false, ""};
+    }
+  } else {
+    auto path = absPath(elem.second);
+    if (pathExists(path)) {
+      res = {true, path};
+    } else {
+      LOG(WARNING) << "Nix search path entry '" << elem.second
+                   << "' does not exist, ignoring";
+      res = {false, ""};
+    }
+  }
+
+  DLOG(INFO) << "resolved search path element '" << elem.second << "' to '"
+             << res.second << "'";
+
+  searchPathResolved[elem.second] = res;
+  return res;
+}
 
 }  // namespace nix