From fa07558a069b974769e22ac944cfe21a69fb4485 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 7 Feb 2017 19:22:48 +0100
Subject: [PATCH] Provide default implementations for a couple of Store methods

---
 src/libstore/binary-cache-store.hh            | 19 -------------------
 src/{nix-store => libstore}/serve-protocol.hh |  0
 src/libstore/store-api.cc                     | 13 +++++++++++++
 src/libstore/store-api.hh                     | 14 +++++++-------
 4 files changed, 20 insertions(+), 26 deletions(-)
 rename src/{nix-store => libstore}/serve-protocol.hh (100%)

diff --git a/src/libstore/binary-cache-store.hh b/src/libstore/binary-cache-store.hh
index 7b228422d..a70d50d49 100644
--- a/src/libstore/binary-cache-store.hh
+++ b/src/libstore/binary-cache-store.hh
@@ -71,9 +71,6 @@ public:
         PathSet & referrers) override
     { notImpl(); }
 
-    PathSet queryValidDerivers(const Path & path) override
-    { return {}; }
-
     PathSet queryDerivationOutputs(const Path & path) override
     { notImpl(); }
 
@@ -83,13 +80,6 @@ public:
     Path queryPathFromHashPart(const string & hashPart) override
     { notImpl(); }
 
-    PathSet querySubstitutablePaths(const PathSet & paths) override
-    { return {}; }
-
-    void querySubstitutablePathInfos(const PathSet & paths,
-        SubstitutablePathInfos & infos) override
-    { }
-
     bool wantMassQuery() override { return wantMassQuery_; }
 
     void addToStore(const ValidPathInfo & info, const ref<std::string> & nar,
@@ -121,21 +111,12 @@ public:
     void addIndirectRoot(const Path & path) override
     { notImpl(); }
 
-    void syncWithGC() override
-    { }
-
     Roots findRoots() override
     { notImpl(); }
 
     void collectGarbage(const GCOptions & options, GCResults & results) override
     { notImpl(); }
 
-    void optimiseStore() override
-    { }
-
-    bool verifyStore(bool checkContents, bool repair) override
-    { return true; }
-
     ref<FSAccessor> getFSAccessor() override;
 
     void addSignatures(const Path & storePath, const StringSet & sigs) override
diff --git a/src/nix-store/serve-protocol.hh b/src/libstore/serve-protocol.hh
similarity index 100%
rename from src/nix-store/serve-protocol.hh
rename to src/libstore/serve-protocol.hh
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index a42d11834..f98ba3840 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -285,6 +285,19 @@ bool Store::isValidPath(const Path & storePath)
 }
 
 
+/* Default implementation for stores that only implement
+   queryPathInfoUncached(). */
+bool Store::isValidPathUncached(const Path & path)
+{
+    try {
+        queryPathInfo(path);
+        return true;
+    } catch (InvalidPath &) {
+        return false;
+    }
+}
+
+
 ref<const ValidPathInfo> Store::queryPathInfo(const Path & storePath)
 {
     std::promise<ref<ValidPathInfo>> promise;
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 3fee99907..8058daf14 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -320,7 +320,7 @@ public:
 
 protected:
 
-    virtual bool isValidPathUncached(const Path & path) = 0;
+    virtual bool isValidPathUncached(const Path & path);
 
 public:
 
@@ -360,7 +360,7 @@ public:
        output.  (Note that the result of `queryDeriver()' is the
        derivation that was actually used to produce `path', which may
        not exist anymore.) */
-    virtual PathSet queryValidDerivers(const Path & path) = 0;
+    virtual PathSet queryValidDerivers(const Path & path) { return {}; };
 
     /* Query the outputs of the derivation denoted by `path'. */
     virtual PathSet queryDerivationOutputs(const Path & path) = 0;
@@ -373,13 +373,13 @@ public:
     virtual Path queryPathFromHashPart(const string & hashPart) = 0;
 
     /* Query which of the given paths have substitutes. */
-    virtual PathSet querySubstitutablePaths(const PathSet & paths) = 0;
+    virtual PathSet querySubstitutablePaths(const PathSet & paths) { return {}; };
 
     /* Query substitute info (i.e. references, derivers and download
        sizes) of a set of paths.  If a path does not have substitute
        info, it's omitted from the resulting ‘infos’ map. */
     virtual void querySubstitutablePathInfos(const PathSet & paths,
-        SubstitutablePathInfos & infos) = 0;
+        SubstitutablePathInfos & infos) { return; };
 
     virtual bool wantMassQuery() { return false; }
 
@@ -454,7 +454,7 @@ public:
          permanent root and sees our's.
 
        In either case the permanent root is seen by the collector. */
-    virtual void syncWithGC() = 0;
+    virtual void syncWithGC() { };
 
     /* Find the roots of the garbage collector.  Each root is a pair
        (link, storepath) where `link' is the path of the symlink
@@ -485,11 +485,11 @@ public:
 
     /* Optimise the disk space usage of the Nix store by hard-linking files
        with the same contents. */
-    virtual void optimiseStore() = 0;
+    virtual void optimiseStore() { };
 
     /* Check the integrity of the Nix store.  Returns true if errors
        remain. */
-    virtual bool verifyStore(bool checkContents, bool repair) = 0;
+    virtual bool verifyStore(bool checkContents, bool repair) { return false; };
 
     /* Return an object to access files in the Nix store. */
     virtual ref<FSAccessor> getFSAccessor() = 0;