Expose the export magic value and move LocalStore::queryReferences to Store

src/libstore/local-store.cc

@@ -953,14 +953,6 @@ PathSet LocalStore::queryAllValidPaths()
 }
 
 
-void LocalStore::queryReferences(const Path & path,
-    PathSet & references)
-{
-    ValidPathInfo info = queryPathInfo(path);
-    references.insert(info.references.begin(), info.references.end());
-}
-
-
 void LocalStore::queryReferrers_(const Path & path, PathSet & referrers)
 {
     SQLiteStmtUse use(stmtQueryReferrers);
@@ -1493,9 +1485,6 @@ struct HashAndWriteSink : Sink
 };
 
 
-#define EXPORT_MAGIC 0x4558494e
-
-
 static void checkSecrecy(const Path & path)
 {
     struct stat st;
@@ -1532,7 +1521,7 @@ void LocalStore::exportPath(const Path & path, bool sign,
     PathSet references;
     queryReferences(path, references);
 
-    hashAndWriteSink << EXPORT_MAGIC << path << references << queryDeriver(path);
+    hashAndWriteSink << exportMagic << path << references << queryDeriver(path);
 
     if (sign) {
         Hash hash = hashAndWriteSink.currentHash();
@@ -1608,8 +1597,8 @@ Path LocalStore::importPath(bool requireSignature, Source & source)
 
     restorePath(unpacked, hashAndReadSource);
 
-    unsigned int magic = readInt(hashAndReadSource);
+    uint32_t magic = readInt(hashAndReadSource);
-    if (magic != EXPORT_MAGIC)
+    if (magic != exportMagic)
         throw Error("Nix archive cannot be imported; wrong format");
 
     Path dstPath = readStorePath(hashAndReadSource);

src/libstore/local-store.hh

@@ -108,8 +108,6 @@ public:
 
     Hash queryPathHash(const Path & path) override;
 
-    void queryReferences(const Path & path, PathSet & references) override;
-
     void queryReferrers(const Path & path, PathSet & referrers) override;
 
     Path queryDeriver(const Path & path) override;

src/libstore/store-api.cc

@@ -224,6 +224,13 @@ Path computeStorePathForText(const string & name, const string & s,
 }
 
 
+void Store::queryReferences(const Path & path, PathSet & references)
+{
+    ValidPathInfo info = queryPathInfo(path);
+    references.insert(info.references.begin(), info.references.end());
+}
+
+
 /* Return a string accepted by decodeValidPathInfo() that
    registers the specified paths as valid.  Note: it's the
    responsibility of the caller to provide a closure. */

src/libstore/store-api.hh

@@ -12,6 +12,13 @@
 namespace nix {
 
 
+/* Size of the hash part of store paths, in base-32 characters. */
+const size_t storePathHashLen = 32; // i.e. 160 bits
+
+/* Magic header of exportPath() output. */
+const uint32_t exportMagic = 0x4558494e;
+
+
 typedef std::map<Path, Path> Roots;
 
 
@@ -158,8 +165,7 @@ public:
 
     /* Query the set of outgoing FS references for a store path. The
        result is not cleared. */
-    virtual void queryReferences(const Path & path,
+    virtual void queryReferences(const Path & path, PathSet & references);
-        PathSet & references) = 0;
 
     /* Queries the set of incoming FS references for a store path.
        The result is not cleared. */
@@ -339,9 +345,6 @@ public:
 };
 
 
-const size_t storePathHashLen = 32; // base-32 characters, i.e. 160 bits
-
-
 /* !!! These should be part of the store API, I guess. */
 
 /* Throw an exception if `path' is not directly in the Nix store. */