libstore: remove unused DownstreamPlaceholder

Change-Id: I3b71778aa9e92bf8ac0edef0ca929e92010f5c6a

lix/libexpr/eval.cc

@@ -14,7 +14,6 @@
 #include "lix/libutil/types.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/derivations.hh"
-#include "lix/libstore/downstream-placeholder.hh"
 #include "lix/libexpr/gc-alloc.hh"
 #include "lix/libstore/filetransfer.hh"
 #include "lix/libexpr/function-trace.hh"

lix/libexpr/eval.hh

@@ -804,8 +804,7 @@ public:
     /**
      * Coerce to `SingleDerivedPath`.
      *
-     * Must be a string which is either a literal store path or a
-     * "placeholder (see `DownstreamPlaceholder`).
+     * Must be a string which is either a literal store path.
      *
      * Even more importantly, the string context must be exactly one
      * element, which is either a `NixStringContextElem::Opaque` or

lix/libexpr/primops.cc

@@ -1,6 +1,5 @@
 #include "lix/libutil/archive.hh"
 #include "lix/libstore/derivations.hh"
-#include "lix/libstore/downstream-placeholder.hh"
 #include "lix/libexpr/eval.hh"
 #include "lix/libexpr/eval-settings.hh"
 #include "lix/libexpr/extra-primops.hh"

lix/libstore/derivations.cc

@@ -1,5 +1,4 @@
 #include "lix/libstore/derivations.hh"
-#include "lix/libstore/downstream-placeholder.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/globals.hh"
 #include "lix/libutil/json.hh"

lix/libstore/downstream-placeholder.cc

@@ -1,33 +0,0 @@
-#include "lix/libstore/downstream-placeholder.hh"
-#include "lix/libstore/derivations.hh"
-
-namespace nix {
-
-std::string DownstreamPlaceholder::render() const
-{
-    return "/" + hash.to_string(Base::Base32, false);
-}
-
-
-DownstreamPlaceholder DownstreamPlaceholder::unknownCaOutput(
-    const StorePath & drvPath,
-    OutputNameView outputName,
-    const ExperimentalFeatureSettings & xpSettings)
-{
-    xpSettings.require(Xp::CaDerivations);
-    auto drvNameWithExtension = drvPath.name();
-    auto drvName = drvNameWithExtension.substr(0, drvNameWithExtension.size() - 4);
-    auto clearText = "nix-upstream-output:" + std::string { drvPath.hashPart() } + ":" + outputPathName(drvName, outputName);
-    return DownstreamPlaceholder {
-        hashString(HashType::SHA256, clearText)
-    };
-}
-
-DownstreamPlaceholder DownstreamPlaceholder::fromSingleDerivedPathBuilt(
-    const SingleDerivedPath::Built & b,
-    const ExperimentalFeatureSettings & xpSettings)
-{
-    return DownstreamPlaceholder::unknownCaOutput(b.drvPath.path, b.output, xpSettings);
-}
-
-}

lix/libstore/downstream-placeholder.hh

@@ -1,77 +0,0 @@
-#pragma once
-///@file
-
-#include "lix/libutil/hash.hh"
-#include "lix/libstore/path.hh"
-#include "lix/libstore/derived-path.hh"
-
-namespace nix {
-
-/**
- * Downstream Placeholders are opaque and almost certainly unique values
- * used to allow derivations to refer to store objects which are yet to
- * be built and for we do not yet have store paths for.
- *
- * They correspond to `DerivedPaths` that are not `DerivedPath::Opaque`,
- * except for the cases involving input addressing or fixed outputs
- * where we do know a store path for the derivation output in advance.
- *
- * Unlike `DerivationPath`, however, `DownstreamPlaceholder` is
- * purposefully opaque and obfuscated. This is so they are hard to
- * create by accident, and so substituting them (once we know what the
- * path to store object is) is unlikely to capture other stuff it
- * shouldn't.
- *
- * We use them with `Derivation`: the `render()` method is called to
- * render an opaque string which can be used in the derivation, and the
- * resolving logic can substitute those strings for store paths when
- * resolving `Derivation.inputDrvs` to `BasicDerivation.inputSrcs`.
- */
-class DownstreamPlaceholder
-{
-    /**
-     * `DownstreamPlaceholder` is just a newtype of `Hash`.
-     * This its only field.
-     */
-    Hash hash;
-
-    /**
-     * Newtype constructor
-     */
-    DownstreamPlaceholder(Hash hash) : hash(hash) { }
-
-public:
-    /**
-     * This creates an opaque and almost certainly unique string
-     * deterministically from the placeholder.
-     */
-    std::string render() const;
-
-    /**
-     * Create a placeholder for an unknown output of a content-addressed
-     * derivation.
-     *
-     * The derivation itself is known (we have a store path for it), but
-     * the output doesn't yet have a known store path.
-     *
-     * @param xpSettings Stop-gap to avoid globals during unit tests.
-     */
-    static DownstreamPlaceholder unknownCaOutput(
-        const StorePath & drvPath,
-        OutputNameView outputName,
-        const ExperimentalFeatureSettings & xpSettings = experimentalFeatureSettings);
-
-    /**
-     * Convenience constructor that handles both cases (unknown
-     * content-addressed output and unknown derivation), delegating as
-     * needed to `unknownCaOutput`.
-     *
-     * Recursively builds up a placeholder from a
-     * `SingleDerivedPath::Built.drvPath` chain.
-     */
-    static DownstreamPlaceholder fromSingleDerivedPathBuilt(
-        const SingleDerivedPath::Built & built,
-        const ExperimentalFeatureSettings & xpSettings = experimentalFeatureSettings);
-};
-
-}

lix/libstore/meson.build

@@ -156,7 +156,6 @@ libstore_sources = files(
   'daemon.cc',
   'derivations.cc',
   'derived-path.cc',
-  'downstream-placeholder.cc',
   'dummy-store.cc',
   'export-import.cc',
   'filetransfer.cc',
@@ -223,7 +222,6 @@ libstore_headers = files(
   'daemon.hh',
   'derivations.hh',
   'derived-path.hh',
-  'downstream-placeholder.hh',
   'dummy-store.hh',
   'filetransfer.hh',
   'fs-accessor.hh',

lix/nix/app.cc

@@ -7,7 +7,6 @@
 #include "lix/libstore/names.hh"
 #include "lix/libcmd/command.hh"
 #include "lix/libstore/derivations.hh"
-#include "lix/libstore/downstream-placeholder.hh"
 
 namespace nix {
 

tests/unit/libstore/downstream-placeholder.cc

@@ -1,23 +0,0 @@
-#include <gtest/gtest.h>
-
-#include "lix/libstore/downstream-placeholder.hh"
-
-namespace nix {
-
-TEST(DownstreamPlaceholder, unknownCaOutput) {
-    /**
-     * We set these in tests rather than the regular globals so we don't have
-     * to worry about race conditions if the tests run concurrently.
-     */
-    ExperimentalFeatureSettings mockXpSettings;
-    mockXpSettings.experimentalFeatures.override(ExperimentalFeatures{} | Xp::CaDerivations);
-
-    ASSERT_EQ(
-        DownstreamPlaceholder::unknownCaOutput(
-            StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo.drv" },
-            "out",
-            mockXpSettings).render(),
-        "/0c6rn30q4frawknapgwq386zq358m8r6msvywcvc89n6m5p2dgbz");
-}
-
-}

tests/unit/meson.build

@@ -136,7 +136,6 @@ libstore_tests_sources = files(
   'libstore/common-protocol.cc',
   'libstore/derivation.cc',
   'libstore/derived-path.cc',
-  'libstore/downstream-placeholder.cc',
   'libstore/filetransfer.cc',
   'libstore/machines.cc',
   'libstore/nar-info-disk-cache.cc',