From d564ac1c5086bda75388d21a25583b2c9809f086 Mon Sep 17 00:00:00 2001
From: Carlo Nucera <carlo.nucera@protonmail.com>
Date: Mon, 27 Jul 2020 16:42:02 -0400
Subject: Offer a safer interface for pathOpt

The new interface we offer provides a way of getting all the
DerivationOutputs with the storePaths directly, based on the observation
that it's the most common usecase.
---
 src/libstore/derivations.hh | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'src/libstore/derivations.hh')

diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh
index b1cda85cb..b0cb870a2 100644
--- a/src/libstore/derivations.hh
+++ b/src/libstore/derivations.hh
@@ -41,6 +41,9 @@ struct DerivationOutput
         DerivationOutputFloating
     > output;
     std::optional<HashType> hashAlgoOpt(const Store & store) const;
+    /* Note, when you use this function you should make sure that you're passing
+       the right derivation name. When in doubt, you should use the safer
+       interface provided by BasicDerivation::outputsAndPaths */
     std::optional<StorePath> pathOpt(const Store & store, std::string_view drvName) const;
     /* DEPRECATED: Remove after CA drvs are fully implemented */
     StorePath path(const Store & store, std::string_view drvName) const {
@@ -52,6 +55,15 @@ struct DerivationOutput
 
 typedef std::map<string, DerivationOutput> DerivationOutputs;
 
+/* These are analogues to the previous DerivationOutputs data type, but they
+   also contains, for each output, the (optional) store path in which it would
+   be written. To calculate values of these types, see the corresponding
+   functions in BasicDerivation */
+typedef std::map<string, std::pair<DerivationOutput, StorePath>>
+  DerivationOutputsAndPaths;
+typedef std::map<string, std::pair<DerivationOutput, std::optional<StorePath>>>
+  DerivationOutputsAndOptPaths;
+
 /* For inputs that are sub-derivations, we specify exactly which
    output IDs we are interested in. */
 typedef std::map<StorePath, StringSet> DerivationInputs;
@@ -101,6 +113,13 @@ struct BasicDerivation
     /* Return the output names of a derivation. */
     StringSet outputNames() const;
 
+    /* Calculates the maps that contains all the DerivationOutputs, but
+       augmented with knowledge of the Store paths they would be written into.
+       The first one of these functions will be removed when the CA work is
+       completed */
+    DerivationOutputsAndPaths outputsAndPaths(const Store & store) const;
+    DerivationOutputsAndOptPaths outputsAndOptPaths(const Store & store) const;
+
     static std::string_view nameFromPath(const StorePath & storePath);
 };
 
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