libstore: split Store::computeStorePathForPath

the two variants compute their store path hashes very differently, and
the flat version ignores the filter passed in by the user entirely. in
a future change we want to move filters out of store methods entirely,
splitting them now will make that task a lot easier when we are ready.

Change-Id: I5f23a26ca08e81923f33adf687056d0d464c2cb8

lix/libfetchers/fetch-to-store.cc

@@ -15,11 +15,20 @@ try {
     Activity act(*logger, lvlChatty, actUnknown, fmt("copying '%s' to the store", path));
 
     auto filter2 = filter ? *filter : defaultPathFilter;
+    auto physicalPath = path.canonical().abs();
 
-    co_return
-        settings.readOnlyMode
-        ? store.computeStorePathForPath(name, path.canonical().abs(), method, filter2)
-        : TRY_AWAIT(store.addToStore(name, path.canonical().abs(), method, HashType::SHA256, filter2, repair));
+    if (settings.readOnlyMode) {
+        switch (method) {
+        case FileIngestionMethod::Recursive:
+            co_return store.computeStorePathForPathRecursive(name, physicalPath, filter2);
+        case FileIngestionMethod::Flat:
+            co_return store.computeStorePathForPathFlat(name, physicalPath);
+        }
+    } else {
+        co_return TRY_AWAIT(
+            store.addToStore(name, physicalPath, method, HashType::SHA256, filter2, repair)
+        );
+    }
 } catch (...) {
     co_return result::current_exception();
 }

lix/libstore/store-api.cc

@@ -246,15 +246,22 @@ StorePath Store::makeFixedOutputPathFromCA(std::string_view name, const ContentA
 }
 
 
-StorePath Store::computeStorePathForPath(std::string_view name,
-    const Path & srcPath, FileIngestionMethod method, PathFilter & filter) const
+StorePath Store::computeStorePathForPathRecursive(std::string_view name,
+    const Path & srcPath, PathFilter & filter) const
 {
-    Hash h = method == FileIngestionMethod::Recursive
-        ? hashPath(HashType::SHA256, srcPath, filter).first
-        : hashFile(HashType::SHA256, srcPath);
     FixedOutputInfo caInfo {
-        .method = method,
-        .hash = h,
+        .method = FileIngestionMethod::Recursive,
+        .hash = hashPath(HashType::SHA256, srcPath, filter).first,
+        .references = {},
+    };
+    return makeFixedOutputPath(name, caInfo);
+}
+
+StorePath Store::computeStorePathForPathFlat(std::string_view name, const Path & srcPath) const
+{
+    FixedOutputInfo caInfo {
+        .method = FileIngestionMethod::Flat,
+        .hash = hashFile(HashType::SHA256, srcPath),
         .references = {},
     };
     return makeFixedOutputPath(name, caInfo);

lix/libstore/store-api.hh

@@ -315,9 +315,10 @@ public:
      *
      * @return the store path to which srcPath is to be copied.
      */
-    StorePath computeStorePathForPath(std::string_view name,
-        const Path & srcPath, FileIngestionMethod method = FileIngestionMethod::Recursive,
-        PathFilter & filter = defaultPathFilter) const;
+    StorePath computeStorePathForPathRecursive(
+        std::string_view name, const Path & srcPath, PathFilter & filter = defaultPathFilter
+    ) const;
+    StorePath computeStorePathForPathFlat(std::string_view name, const Path & srcPath) const;
 
     /**
      * Preparatory part of addTextToStore().