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

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

src/libcmd/common-eval-args.cc

@@ -93,9 +93,9 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
 
 SourcePath lookupFileArg(EvalState & state, std::string_view s)
 {
-    if (isUri(s)) {
+    if (EvalSettings::isPseudoUrl(s)) {
         auto storePath = fetchers::downloadTarball(
-            state.store, resolveUri(s), "source", false).first;
+            state.store, EvalSettings::resolvePseudoUrl(s), "source", false).first;
         auto accessor = makeStorePathAccessor(state.store, storePath);
         state.registerAccessor(accessor);
         return {accessor, CanonPath::root};

src/libexpr/eval.cc

@@ -405,7 +405,7 @@ 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;
             }
@@ -2563,6 +2563,23 @@ 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);

src/libexpr/eval.hh

@@ -602,6 +602,10 @@ struct EvalSettings : Config
 
     static Strings getDefaultNixPath();
 
+    static bool isPseudoUrl(std::string_view s);
+
+    static std::string resolvePseudoUrl(std::string_view url);
+
     Setting<bool> enableNativeCode{this, false, "allow-unsafe-native-code-during-evaluation",
         "Whether builtin functions that allow executing native code should be enabled."};
 

src/libexpr/parser.y

@@ -776,17 +776,17 @@ SourcePath EvalState::findFile(SearchPath & searchPath, const std::string_view p
 }
 
 
- std::optional<SourcePath> EvalState::resolveSearchPathElem(const SearchPathElem & elem, bool initAccessControl)
+std::optional<SourcePath> EvalState::resolveSearchPathElem(const SearchPathElem & elem, bool initAccessControl)
 {
     auto i = searchPathResolved.find(elem.second);
     if (i != searchPathResolved.end()) return i->second;
 
     std::optional<SourcePath> res;
 
-    if (isUri(elem.second)) {
+    if (EvalSettings::isPseudoUrl(elem.second)) {
         try {
             auto storePath = fetchers::downloadTarball(
-                store, resolveUri(elem.second), "source", false).first;
+                store, EvalSettings::resolvePseudoUrl(elem.second), "source", false).first;
             auto accessor = makeStorePathAccessor(store, storePath);
             registerAccessor(accessor);
             res.emplace(SourcePath {accessor, CanonPath::root});

src/libexpr/primops/fetchTree.cc

@@ -257,8 +257,6 @@ static void fetch(EvalState & state, const PosIdx pos, Value * * args, Value & v
     } else
         url = state.forceStringNoCtx(*args[0], pos);
 
-    url = resolveUri(*url);
-
     state.checkURI(*url);
 
     if (name == "")

src/libstore/filetransfer.cc

@@ -33,14 +33,6 @@ FileTransferSettings fileTransferSettings;
 
 static GlobalConfig::Register rFileTransferSettings(&fileTransferSettings);
 
-std::string resolveUri(std::string_view uri)
-{
-    if (uri.compare(0, 8, "channel:") == 0)
-        return "https://nixos.org/channels/" + std::string(uri.substr(8)) + "/nixexprs.tar.xz";
-    else
-        return std::string(uri);
-}
-
 struct curlFileTransfer : public FileTransfer
 {
     CURLM * curlm = 0;
@@ -874,14 +866,4 @@ FileTransferError::FileTransferError(FileTransfer::Error error, std::optional<st
         err.msg = hf;
 }
 
-bool isUri(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";
-}
-
-
 }

src/libstore/filetransfer.hh

@@ -125,9 +125,4 @@ public:
     FileTransferError(FileTransfer::Error error, std::optional<std::string> response, const Args & ... args);
 };
 
-bool isUri(std::string_view s);
-
-/* Resolve deprecated 'channel:<foo>' URLs. */
-std::string resolveUri(std::string_view uri);
-
 }