Move /src to /subprojects

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

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

@@ -0,0 +1,213 @@
+#include "http-binary-cache-store.hh"
+#include "filetransfer.hh"
+#include "globals.hh"
+#include "nar-info-disk-cache.hh"
+#include "callback.hh"
+
+namespace nix {
+
+MakeError(UploadToHTTP, Error);
+
+
+HttpBinaryCacheStoreConfig::HttpBinaryCacheStoreConfig(
+    std::string_view scheme,
+    std::string_view _cacheUri,
+    const Params & params)
+    : StoreConfig(params)
+    , BinaryCacheStoreConfig(params)
+    , cacheUri(
+        std::string { scheme }
+        + "://"
+        + (!_cacheUri.empty()
+            ? _cacheUri
+            : throw UsageError("`%s` Store requires a non-empty authority in Store URL", scheme)))
+{
+    while (!cacheUri.empty() && cacheUri.back() == '/')
+        cacheUri.pop_back();
+}
+
+
+std::string HttpBinaryCacheStoreConfig::doc()
+{
+    return
+      #include "http-binary-cache-store.md"
+      ;
+}
+
+
+class HttpBinaryCacheStore : public virtual HttpBinaryCacheStoreConfig, public virtual BinaryCacheStore
+{
+private:
+
+    struct State
+    {
+        bool enabled = true;
+        std::chrono::steady_clock::time_point disabledUntil;
+    };
+
+    Sync<State> _state;
+
+public:
+
+    HttpBinaryCacheStore(
+        std::string_view scheme,
+        PathView cacheUri,
+        const Params & params)
+        : StoreConfig(params)
+        , BinaryCacheStoreConfig(params)
+        , HttpBinaryCacheStoreConfig(scheme, cacheUri, params)
+        , Store(params)
+        , BinaryCacheStore(params)
+    {
+        diskCache = getNarInfoDiskCache();
+    }
+
+    std::string getUri() override
+    {
+        return cacheUri;
+    }
+
+    void init() override
+    {
+        // FIXME: do this lazily?
+        if (auto cacheInfo = diskCache->upToDateCacheExists(cacheUri)) {
+            wantMassQuery.setDefault(cacheInfo->wantMassQuery);
+            priority.setDefault(cacheInfo->priority);
+        } else {
+            try {
+                BinaryCacheStore::init();
+            } catch (UploadToHTTP &) {
+                throw Error("'%s' does not appear to be a binary cache", cacheUri);
+            }
+            diskCache->createCache(cacheUri, storeDir, wantMassQuery, priority);
+        }
+    }
+
+protected:
+
+    void maybeDisable()
+    {
+        auto state(_state.lock());
+        if (state->enabled && settings.tryFallback) {
+            int t = 60;
+            printError("disabling binary cache '%s' for %s seconds", getUri(), t);
+            state->enabled = false;
+            state->disabledUntil = std::chrono::steady_clock::now() + std::chrono::seconds(t);
+        }
+    }
+
+    void checkEnabled()
+    {
+        auto state(_state.lock());
+        if (state->enabled) return;
+        if (std::chrono::steady_clock::now() > state->disabledUntil) {
+            state->enabled = true;
+            debug("re-enabling binary cache '%s'", getUri());
+            return;
+        }
+        throw SubstituterDisabled("substituter '%s' is disabled", getUri());
+    }
+
+    bool fileExists(const std::string & path) override
+    {
+        checkEnabled();
+
+        try {
+            FileTransferRequest request(makeRequest(path));
+            request.head = true;
+            getFileTransfer()->download(request);
+            return true;
+        } catch (FileTransferError & e) {
+            /* S3 buckets return 403 if a file doesn't exist and the
+               bucket is unlistable, so treat 403 as 404. */
+            if (e.error == FileTransfer::NotFound || e.error == FileTransfer::Forbidden)
+                return false;
+            maybeDisable();
+            throw;
+        }
+    }
+
+    void upsertFile(const std::string & path,
+        std::shared_ptr<std::basic_iostream<char>> istream,
+        const std::string & mimeType) override
+    {
+        auto req = makeRequest(path);
+        req.data = StreamToSourceAdapter(istream).drain();
+        req.mimeType = mimeType;
+        try {
+            getFileTransfer()->upload(req);
+        } catch (FileTransferError & e) {
+            throw UploadToHTTP("while uploading to HTTP binary cache at '%s': %s", cacheUri, e.msg());
+        }
+    }
+
+    FileTransferRequest makeRequest(const std::string & path)
+    {
+        return FileTransferRequest(
+            hasPrefix(path, "https://") || hasPrefix(path, "http://") || hasPrefix(path, "file://")
+            ? path
+            : cacheUri + "/" + path);
+
+    }
+
+    void getFile(const std::string & path, Sink & sink) override
+    {
+        checkEnabled();
+        auto request(makeRequest(path));
+        try {
+            getFileTransfer()->download(std::move(request), sink);
+        } catch (FileTransferError & e) {
+            if (e.error == FileTransfer::NotFound || e.error == FileTransfer::Forbidden)
+                throw NoSuchBinaryCacheFile("file '%s' does not exist in binary cache '%s'", path, getUri());
+            maybeDisable();
+            throw;
+        }
+    }
+
+    void getFile(const std::string & path,
+        Callback<std::optional<std::string>> callback) noexcept override
+    {
+        try {
+            checkEnabled();
+
+            auto request(makeRequest(path));
+
+            auto callbackPtr = std::make_shared<decltype(callback)>(std::move(callback));
+
+            getFileTransfer()->enqueueFileTransfer(request,
+                {[callbackPtr, this](std::future<FileTransferResult> result) {
+                    try {
+                        (*callbackPtr)(std::move(result.get().data));
+                    } catch (FileTransferError & e) {
+                        if (e.error == FileTransfer::NotFound || e.error == FileTransfer::Forbidden)
+                            return (*callbackPtr)({});
+                        maybeDisable();
+                        callbackPtr->rethrow();
+                    } catch (...) {
+                        callbackPtr->rethrow();
+                    }
+            }});
+
+        } catch (...) {
+            callback.rethrow();
+            return;
+        }
+    }
+
+    /**
+     * This isn't actually necessary read only. We support "upsert" now, so we
+     * have a notion of authentication via HTTP POST/PUT.
+     *
+     * For now, we conservatively say we don't know.
+     *
+     * \todo try to expose our HTTP authentication status.
+     */
+    std::optional<TrustedFlag> isTrustedClient() override
+    {
+        return std::nullopt;
+    }
+};
+
+static RegisterStoreImplementation<HttpBinaryCacheStore, HttpBinaryCacheStoreConfig> regHttpBinaryCacheStore;
+
+}