Move /src to /subprojects

This will facilitate breaking up Nix into multiple packages for each
component with Meson.

subprojects/libstore/local-binary-cache-store.cc

@@ -0,0 +1,132 @@
+#include "local-binary-cache-store.hh"
+#include "globals.hh"
+#include "nar-info-disk-cache.hh"
+#include "signals.hh"
+
+#include <atomic>
+
+namespace nix {
+
+LocalBinaryCacheStoreConfig::LocalBinaryCacheStoreConfig(
+    std::string_view scheme,
+    PathView binaryCacheDir,
+    const Params & params)
+    : StoreConfig(params)
+    , BinaryCacheStoreConfig(params)
+    , binaryCacheDir(binaryCacheDir)
+{
+}
+
+
+std::string LocalBinaryCacheStoreConfig::doc()
+{
+    return
+      #include "local-binary-cache-store.md"
+      ;
+}
+
+
+struct LocalBinaryCacheStore : virtual LocalBinaryCacheStoreConfig, virtual BinaryCacheStore
+{
+    /**
+     * @param binaryCacheDir `file://` is a short-hand for `file:///`
+     * for now.
+     */
+    LocalBinaryCacheStore(
+        std::string_view scheme,
+        PathView binaryCacheDir,
+        const Params & params)
+        : StoreConfig(params)
+        , BinaryCacheStoreConfig(params)
+        , LocalBinaryCacheStoreConfig(scheme, binaryCacheDir, params)
+        , Store(params)
+        , BinaryCacheStore(params)
+    {
+    }
+
+    void init() override;
+
+    std::string getUri() override
+    {
+        return "file://" + binaryCacheDir;
+    }
+
+protected:
+
+    bool fileExists(const std::string & path) override;
+
+    void upsertFile(const std::string & path,
+        std::shared_ptr<std::basic_iostream<char>> istream,
+        const std::string & mimeType) override
+    {
+        auto path2 = binaryCacheDir + "/" + path;
+        static std::atomic<int> counter{0};
+        Path tmp = fmt("%s.tmp.%d.%d", path2, getpid(), ++counter);
+        AutoDelete del(tmp, false);
+        StreamToSourceAdapter source(istream);
+        writeFile(tmp, source);
+        std::filesystem::rename(tmp, path2);
+        del.cancel();
+    }
+
+    void getFile(const std::string & path, Sink & sink) override
+    {
+        try {
+            readFile(binaryCacheDir + "/" + path, sink);
+        } catch (SysError & e) {
+            if (e.errNo == ENOENT)
+                throw NoSuchBinaryCacheFile("file '%s' does not exist in binary cache", path);
+            throw;
+        }
+    }
+
+    StorePathSet queryAllValidPaths() override
+    {
+        StorePathSet paths;
+
+        for (auto & entry : std::filesystem::directory_iterator{binaryCacheDir}) {
+            checkInterrupt();
+            auto name = entry.path().filename().string();
+            if (name.size() != 40 ||
+                !hasSuffix(name, ".narinfo"))
+                continue;
+            paths.insert(parseStorePath(
+                    storeDir + "/" + name.substr(0, name.size() - 8)
+                    + "-" + MissingName));
+        }
+
+        return paths;
+    }
+
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return Trusted;
+    }
+};
+
+void LocalBinaryCacheStore::init()
+{
+    createDirs(binaryCacheDir + "/nar");
+    createDirs(binaryCacheDir + "/" + realisationsPrefix);
+    if (writeDebugInfo)
+        createDirs(binaryCacheDir + "/debuginfo");
+    createDirs(binaryCacheDir + "/log");
+    BinaryCacheStore::init();
+}
+
+bool LocalBinaryCacheStore::fileExists(const std::string & path)
+{
+    return pathExists(binaryCacheDir + "/" + path);
+}
+
+std::set<std::string> LocalBinaryCacheStoreConfig::uriSchemes()
+{
+    if (getEnv("_NIX_FORCE_HTTP") == "1")
+        return {};
+    else
+        return {"file"};
+}
+
+static RegisterStoreImplementation<LocalBinaryCacheStore, LocalBinaryCacheStoreConfig> regLocalBinaryCacheStore;
+
+}