Move isUri() and resolveUri() out of filetransfer.cc

These are purely related to NIX_PATH / -I command line parsing, so put
them in libexpr.

1 files changed, 18 insertions, 1 deletions

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index b67ed853e..ca8d634da 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -402,7 +402,7 @@ static Strings parseNixPath(const std::string & s)
         }
 
         if (*p == ':') {
-            if (isUri(std::string(start2, s.end()))) {
+            if (EvalSettings::isPseudoUrl(std::string(start2, s.end()))) {
                 ++p;
                 while (p != s.end() && *p != ':') ++p;
             }
@@ -2583,6 +2583,23 @@ Strings EvalSettings::getDefaultNixPath()
     return res;
 }
 
+bool EvalSettings::isPseudoUrl(std::string_view s)
+{
+    if (s.compare(0, 8, "channel:") == 0) return true;
+    size_t pos = s.find("://");
+    if (pos == std::string::npos) return false;
+    std::string scheme(s, 0, pos);
+    return scheme == "http" || scheme == "https" || scheme == "file" || scheme == "channel" || scheme == "git" || scheme == "s3" || scheme == "ssh";
+}
+
+std::string EvalSettings::resolvePseudoUrl(std::string_view url)
+{
+    if (hasPrefix(url, "channel:"))
+        return "https://nixos.org/channels/" + std::string(url.substr(8)) + "/nixexprs.tar.xz";
+    else
+        return std::string(url);
+}
+
 EvalSettings evalSettings;
 
 static GlobalConfig::Register rEvalSettings(&evalSettings);