Move 'nix hash-*' and 'nix to-*' to 'nix hash'

From the 'nix' UX review.

src/nix/hash.cc

@@ -8,7 +8,7 @@
 
 using namespace nix;
 
-struct CmdHash : Command
+struct CmdHashBase : Command
 {
     FileIngestionMethod mode;
     Base base = SRI;
@@ -17,7 +17,7 @@ struct CmdHash : Command
     std::vector<std::string> paths;
     std::optional<std::string> modulus;
 
-    CmdHash(FileIngestionMethod mode) : mode(mode)
+    CmdHashBase(FileIngestionMethod mode) : mode(mode)
     {
         mkFlag(0, "sri", "print hash in SRI format", &base, SRI);
         mkFlag(0, "base64", "print hash in base-64", &base, Base64);
@@ -51,8 +51,6 @@ struct CmdHash : Command
         return d;
     }
 
-    Category category() override { return catUtility; }
-
     void run() override
     {
         for (auto path : paths) {
@@ -79,9 +77,6 @@ struct CmdHash : Command
     }
 };
 
-static RegisterCommand rCmdHashFile("hash-file", [](){ return make_ref<CmdHash>(FileIngestionMethod::Flat); });
-static RegisterCommand rCmdHashPath("hash-path", [](){ return make_ref<CmdHash>(FileIngestionMethod::Recursive); });
-
 struct CmdToBase : Command
 {
     Base base;
@@ -103,8 +98,6 @@ struct CmdToBase : Command
             "SRI");
     }
 
-    Category category() override { return catUtility; }
-
     void run() override
     {
         for (auto s : args)
@@ -112,10 +105,41 @@ struct CmdToBase : Command
     }
 };
 
-static RegisterCommand rCmdToBase16("to-base16", [](){ return make_ref<CmdToBase>(Base16); });
-static RegisterCommand rCmdToBase32("to-base32", [](){ return make_ref<CmdToBase>(Base32); });
-static RegisterCommand rCmdToBase64("to-base64", [](){ return make_ref<CmdToBase>(Base64); });
-static RegisterCommand rCmdToSRI("to-sri", [](){ return make_ref<CmdToBase>(SRI); });
+struct CmdHash : NixMultiCommand
+{
+    CmdHash()
+        : MultiCommand({
+                {"file", []() { return make_ref<CmdHashBase>(FileIngestionMethod::Flat);; }},
+                {"path", []() { return make_ref<CmdHashBase>(FileIngestionMethod::Recursive); }},
+                {"to-base16", []() { return make_ref<CmdToBase>(Base16); }},
+                {"to-base32", []() { return make_ref<CmdToBase>(Base32); }},
+                {"to-base64", []() { return make_ref<CmdToBase>(Base64); }},
+                {"to-sri", []() { return make_ref<CmdToBase>(SRI); }},
+          })
+    { }
+
+    std::string description() override
+    {
+        return "compute and convert cryptographic hashes";
+    }
+
+    Category category() override { return catUtility; }
+
+    void run() override
+    {
+        if (!command)
+            throw UsageError("'nix hash' requires a sub-command.");
+        command->second->prepare();
+        command->second->run();
+    }
+
+    void printHelp(const string & programName, std::ostream & out) override
+    {
+        MultiCommand::printHelp(programName, out);
+    }
+};
+
+static auto rCmdHash = registerCommand<CmdHash>("hash");
 
 /* Legacy nix-hash command. */
 static int compatNixHash(int argc, char * * argv)
@@ -149,7 +173,7 @@ static int compatNixHash(int argc, char * * argv)
     });
 
     if (op == opHash) {
-        CmdHash cmd(flat ? FileIngestionMethod::Flat : FileIngestionMethod::Recursive);
+        CmdHashBase cmd(flat ? FileIngestionMethod::Flat : FileIngestionMethod::Recursive);
         cmd.ht = ht;
         cmd.base = base32 ? Base32 : Base16;
         cmd.truncate = truncate;

tests/brotli.sh

@@ -9,13 +9,13 @@ outPath=$(nix-build dependencies.nix --no-out-link)
 
 nix copy --to $cacheURI $outPath
 
-HASH=$(nix hash-path $outPath)
+HASH=$(nix hash path $outPath)
 
 clearStore
 clearCacheCache
 
 nix copy --from $cacheURI $outPath --no-check-sigs
 
-HASH2=$(nix hash-path $outPath)
+HASH2=$(nix hash path $outPath)
 
 [[ $HASH = $HASH2 ]]

tests/fetchurl.sh

@@ -12,7 +12,7 @@ cmp $outPath fetchurl.sh
 # Now using a base-64 hash.
 clearStore
 
-hash=$(nix hash-file --type sha512 --base64 ./fetchurl.sh)
+hash=$(nix hash file --type sha512 --base64 ./fetchurl.sh)
 
 outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file://$(pwd)/fetchurl.sh --argstr sha512 $hash --no-out-link)
 
@@ -21,7 +21,7 @@ cmp $outPath fetchurl.sh
 # Now using an SRI hash.
 clearStore
 
-hash=$(nix hash-file ./fetchurl.sh)
+hash=$(nix hash file ./fetchurl.sh)
 
 [[ $hash =~ ^sha256- ]]
 
@@ -34,14 +34,14 @@ clearStore
 
 other_store=file://$TEST_ROOT/other_store?store=/fnord/store
 
-hash=$(nix hash-file --type sha256 --base16 ./fetchurl.sh)
+hash=$(nix hash file --type sha256 --base16 ./fetchurl.sh)
 
 storePath=$(nix --store $other_store add-to-store --flat ./fetchurl.sh)
 
 outPath=$(nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr sha256 $hash --no-out-link --substituters $other_store)
 
 # Test hashed mirrors with an SRI hash.
-nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr hash $(nix to-sri --type sha256 $hash) \
+nix-build '<nix/fetchurl.nix>' --argstr url file:///no-such-dir/fetchurl.sh --argstr hash $(nix hash to-sri --type sha256 $hash) \
           --no-out-link --substituters $other_store
 
 # Test unpacking a NAR.

tests/hash.sh

@@ -2,7 +2,7 @@ source common.sh
 
 try () {
     printf "%s" "$2" > $TEST_ROOT/vector
-    hash=$(nix hash-file --base16 $EXTRA --type "$1" $TEST_ROOT/vector)
+    hash=$(nix hash file --base16 $EXTRA --type "$1" $TEST_ROOT/vector)
     if test "$hash" != "$3"; then
         echo "hash $1, expected $3, got $hash"
         exit 1
@@ -69,17 +69,17 @@ try2 md5 "f78b733a68f5edbdf9413899339eaa4a"
 
 # Conversion.
 try3() {
-    h64=$(nix to-base64 --type "$1" "$2")
+    h64=$(nix hash to-base64 --type "$1" "$2")
     [ "$h64" = "$4" ]
-    sri=$(nix to-sri --type "$1" "$2")
+    sri=$(nix hash to-sri --type "$1" "$2")
     [ "$sri" = "$1-$4" ]
     h32=$(nix-hash --type "$1" --to-base32 "$2")
     [ "$h32" = "$3" ]
     h16=$(nix-hash --type "$1" --to-base16 "$h32")
     [ "$h16" = "$2" ]
-    h16=$(nix to-base16 --type "$1" "$h64")
+    h16=$(nix hash to-base16 --type "$1" "$h64")
     [ "$h16" = "$2" ]
-    h16=$(nix to-base16 "$sri")
+    h16=$(nix hash to-base16 "$sri")
     [ "$h16" = "$2" ]
 }
 try3 sha1 "800d59cfcd3c05e900cb4e214be48f6b886a08df" "vw46m23bizj4n8afrc0fj19wrp7mj3c0" "gA1Zz808BekAy04hS+SPa4hqCN8="

tests/pure-eval.sh

@@ -15,7 +15,7 @@ nix eval --expr 'assert 1 + 2 == 3; true'
 
 [[ $(nix eval --impure --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; })).x") == 123 ]]
 (! nix eval --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; })).x")
-nix eval --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; sha256 = \"$(nix hash-file pure-eval.nix --type sha256)\"; })).x"
+nix eval --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; sha256 = \"$(nix hash file pure-eval.nix --type sha256)\"; })).x"
 
 rm -rf $TEST_ROOT/eval-out
 nix eval --store dummy:// --write-to $TEST_ROOT/eval-out --expr '{ x = "foo" + "bar"; y = { z = "bla"; }; }'

tests/tarball.sh

@@ -10,7 +10,7 @@ mkdir -p $tarroot
 cp dependencies.nix $tarroot/default.nix
 cp config.nix dependencies.builder*.sh $tarroot/
 
-hash=$(nix hash-path $tarroot)
+hash=$(nix hash path $tarroot)
 
 test_tarball() {
     local ext="$1"