1 files changed, 151 insertions, 0 deletions
diff --git a/src/nix-env/user-env.cc b/src/nix-env/user-env.cc
new file mode 100644
index 000000000000..3bc31b9eafeb
--- /dev/null
+++ b/src/nix-env/user-env.cc
@@ -0,0 +1,151 @@
+#include "user-env.hh"
+#include "util.hh"
+#include "derivations.hh"
+#include "store-api.hh"
+#include "globals.hh"
+#include "shared.hh"
+#include "eval.hh"
+#include "eval-inline.hh"
+#include "profiles.hh"
+
+
+namespace nix {
+
+
+DrvInfos queryInstalled(EvalState & state, const Path & userEnv)
+{
+    DrvInfos elems;
+    Path manifestFile = userEnv + "/manifest.nix";
+    if (pathExists(manifestFile)) {
+        Value v;
+        state.evalFile(manifestFile, v);
+        Bindings & bindings(*state.allocBindings(0));
+        getDerivations(state, v, "", bindings, elems, false);
+    }
+    return elems;
+}
+
+
+bool createUserEnv(EvalState & state, DrvInfos & elems,
+    const Path & profile, bool keepDerivations,
+    const string & lockToken)
+{
+    /* Build the components in the user environment, if they don't
+       exist already. */
+    PathSet drvsToBuild;
+    foreach (DrvInfos::iterator, i, elems)
+        if (i->queryDrvPath() != "")
+            drvsToBuild.insert(i->queryDrvPath());
+
+    debug(format("building user environment dependencies"));
+    store->buildPaths(drvsToBuild, state.repair ? bmRepair : bmNormal);
+
+    /* Construct the whole top level derivation. */
+    PathSet references;
+    Value manifest;
+    state.mkList(manifest, elems.size());
+    unsigned int n = 0;
+    foreach (DrvInfos::iterator, i, elems) {
+        /* Create a pseudo-derivation containing the name, system,
+           output paths, and optionally the derivation path, as well
+           as the meta attributes. */
+        Path drvPath = keepDerivations ? i->queryDrvPath() : "";
+
+        Value & v(*state.allocValue());
+        manifest.list.elems[n++] = &v;
+        state.mkAttrs(v, 16);
+
+        mkString(*state.allocAttr(v, state.sType), "derivation");
+        mkString(*state.allocAttr(v, state.sName), i->name);
+        if (!i->system.empty())
+            mkString(*state.allocAttr(v, state.sSystem), i->system);
+        mkString(*state.allocAttr(v, state.sOutPath), i->queryOutPath());
+        if (drvPath != "")
+            mkString(*state.allocAttr(v, state.sDrvPath), i->queryDrvPath());
+
+        // Copy each output.
+        DrvInfo::Outputs outputs = i->queryOutputs();
+        Value & vOutputs = *state.allocAttr(v, state.sOutputs);
+        state.mkList(vOutputs, outputs.size());
+        unsigned int m = 0;
+        foreach (DrvInfo::Outputs::iterator, j, outputs) {
+            mkString(*(vOutputs.list.elems[m++] = state.allocValue()), j->first);
+            Value & vOutputs = *state.allocAttr(v, state.symbols.create(j->first));
+            state.mkAttrs(vOutputs, 2);
+            mkString(*state.allocAttr(vOutputs, state.sOutPath), j->second);
+
+            /* This is only necessary when installing store paths, e.g.,
+               `nix-env -i /nix/store/abcd...-foo'. */
+            store->addTempRoot(j->second);
+            store->ensurePath(j->second);
+
+            references.insert(j->second);
+        }
+
+        // Copy the meta attributes.
+        Value & vMeta = *state.allocAttr(v, state.sMeta);
+        state.mkAttrs(vMeta, 16);
+        StringSet metaNames = i->queryMetaNames();
+        foreach (StringSet::iterator, j, metaNames) {
+            Value * v = i->queryMeta(*j);
+            if (!v) continue;
+            vMeta.attrs->push_back(Attr(state.symbols.create(*j), v));
+        }
+        vMeta.attrs->sort();
+        v.attrs->sort();
+
+        if (drvPath != "") references.insert(drvPath);
+    }
+
+    /* Also write a copy of the list of user environment elements to
+       the store; we need it for future modifications of the
+       environment. */
+    Path manifestFile = store->addTextToStore("env-manifest.nix",
+        (format("%1%") % manifest).str(), references);
+
+    /* Get the environment builder expression. */
+    Value envBuilder;
+    state.evalFile(state.findFile("nix/buildenv.nix"), envBuilder);
+
+    /* Construct a Nix expression that calls the user environment
+       builder with the manifest as argument. */
+    Value args, topLevel;
+    state.mkAttrs(args, 3);
+    mkString(*state.allocAttr(args, state.symbols.create("manifest")),
+        manifestFile, singleton<PathSet>(manifestFile));
+    args.attrs->push_back(Attr(state.symbols.create("derivations"), &manifest));
+    args.attrs->sort();
+    mkApp(topLevel, envBuilder, args);
+
+    /* Evaluate it. */
+    debug("evaluating user environment builder");
+    state.forceValue(topLevel);
+    PathSet context;
+    Attr & aDrvPath(*topLevel.attrs->find(state.sDrvPath));
+    Path topLevelDrv = state.coerceToPath(aDrvPath.pos ? *(aDrvPath.pos) : noPos, *(aDrvPath.value), context);
+    Attr & aOutPath(*topLevel.attrs->find(state.sOutPath));
+    Path topLevelOut = state.coerceToPath(aOutPath.pos ? *(aOutPath.pos) : noPos, *(aOutPath.value), context);
+
+    /* Realise the resulting store expression. */
+    debug("building user environment");
+    store->buildPaths(singleton<PathSet>(topLevelDrv), state.repair ? bmRepair : bmNormal);
+
+    /* Switch the current user environment to the output path. */
+    PathLocks lock;
+    lockProfile(lock, profile);
+
+    Path lockTokenCur = optimisticLockProfile(profile);
+    if (lockToken != lockTokenCur) {
+        printMsg(lvlError, format("profile ‘%1%’ changed while we were busy; restarting") % profile);
+        return false;
+    }
+
+    debug(format("switching to new user environment"));
+    Path generation = createGeneration(profile, topLevelOut);
+    switchLink(profile, generation);
+
+    return true;
+}
+
+
+}