* nix-env: a tool to manage user environments.

* Replace all directory reading code by a generic readDirectory()
  function.

2 files changed, 281 insertions, 0 deletions

diff --git a/src/nix-env/Makefile.am b/src/nix-env/Makefile.am
new file mode 100644
index 000000000..add54581b
--- /dev/null
+++ b/src/nix-env/Makefile.am
@@ -0,0 +1,11 @@
+bin_PROGRAMS = nix-env
+
+nix_env_SOURCES = main.cc
+nix_env_LDADD = ../libmain/libmain.a ../libexpr/libexpr.a \
+ ../libstore/libstore.a ../libutil/libutil.a \
+ ../boost/format/libformat.a -L../../externals/inst/lib -ldb_cxx \
+ -lsglr -lATB -lconversion -lasfix2 -lmept -lATerm
+
+AM_CXXFLAGS = \
+ -I.. -I../../externals/inst/include -I../libutil -I../libstore \
+ -I../libexpr -I../libmain
diff --git a/src/nix-env/main.cc b/src/nix-env/main.cc
new file mode 100644
index 000000000..4296ce509
--- /dev/null
+++ b/src/nix-env/main.cc
@@ -0,0 +1,270 @@
+#include "globals.hh"
+#include "normalise.hh"
+#include "shared.hh"
+#include "parser.hh"
+#include "eval.hh"
+
+
+typedef void (* Operation) (EvalState & state,
+    Strings opFlags, Strings opArgs);
+
+
+struct DrvInfo
+{
+    string name;
+    Path drvPath;
+    Path outPath;
+};
+
+typedef map<string, DrvInfo> DrvInfos;
+
+
+bool parseDerivation(EvalState & state, Expr e, DrvInfo & drv)
+{
+    ATMatcher m;
+    
+    e = evalExpr(state, e);
+    if (!(atMatch(m, e) >> "Attrs")) return false;
+    Expr a = queryAttr(e, "type");
+    if (!a || evalString(state, a) != "derivation") return false;
+
+    a = queryAttr(e, "name");
+    if (!a) throw badTerm("derivation name missing", e);
+    drv.name = evalString(state, a);
+
+    a = queryAttr(e, "drvPath");
+    if (!a) throw badTerm("derivation path missing", e);
+    drv.drvPath = evalPath(state, a);
+
+    a = queryAttr(e, "outPath");
+    if (!a) throw badTerm("output path missing", e);
+    drv.outPath = evalPath(state, a);
+
+    return true;
+}
+
+
+bool parseDerivations(EvalState & state, Expr e, DrvInfos & drvs)
+{
+    e = evalExpr(state, e);
+    
+    ATermMap drvMap;
+    queryAllAttrs(e, drvMap);
+
+    for (ATermIterator i(drvMap.keys()); i; ++i) {
+        DrvInfo drv;
+        debug(format("evaluating attribute `%1%'") % *i);
+        if (parseDerivation(state, drvMap.get(*i), drv))
+            drvs[drv.name] = drv;
+    }
+
+    return true;
+}
+
+
+void loadDerivations(EvalState & state, Path nePath, DrvInfos & drvs)
+{
+    Expr e = parseExprFromFile(absPath(nePath));
+    if (!parseDerivations(state, e, drvs))
+        throw badTerm("expected set of derivations", e);
+}
+
+
+static Path getLinksDir()
+{
+    return canonPath(nixStateDir + "/links");
+}
+
+
+Path createLink(Path outPath, Path drvPath)
+{
+    Path linksDir = getLinksDir();
+
+    unsigned int num = 0;
+    
+    Strings names = readDirectory(linksDir);
+    for (Strings::iterator i = names.begin(); i != names.end(); ++i) {
+        istringstream s(*i);
+        unsigned int n; 
+        if (s >> n && s.eof() && n > num) num = n + 1;
+    }
+
+    Path linkPath = (format("%1%/%2%") % linksDir % num).str();
+
+    if (symlink(outPath.c_str(), linkPath.c_str()) != 0)
+        throw SysError(format("creating symlink `%1%'") % linkPath);
+
+    return linkPath;
+}
+
+
+void installDerivations(EvalState & state,
+    Path nePath, Strings drvNames)
+{
+    debug(format("installing derivations from `%1%'") % nePath);
+
+    /* Fetch all derivations from the input file. */
+    DrvInfos availDrvs;
+    loadDerivations(state, nePath, availDrvs);
+
+    /* Filter out the ones we're not interested in. */
+    DrvInfos selectedDrvs;
+    for (Strings::iterator i = drvNames.begin();
+         i != drvNames.end(); ++i)
+    {
+        DrvInfos::iterator j = availDrvs.find(*i);
+        if (j == availDrvs.end())
+            throw Error(format("unknown derivation `%1%'") % *i);
+        else
+            selectedDrvs[j->first] = j->second;
+    }
+
+    /* Get the environment builder expression. */
+    Expr envBuilder = parseExprFromFile("/home/eelco/nix/corepkgs/buildenv"); /* !!! */
+
+    /* Construct the whole top level derivation. */
+    ATermList inputs = ATempty;
+    for (DrvInfos::iterator i = selectedDrvs.begin();
+         i != selectedDrvs.end(); ++i)
+    {
+        ATerm t = ATmake(
+            "Attrs(["
+            "Bind(\"type\", Str(\"derivation\")), "
+            "Bind(\"name\", Str(<str>)), "
+            "Bind(\"drvPath\", Path(<str>)), "
+            "Bind(\"outPath\", Path(<str>))"
+            "])",
+            i->second.name.c_str(),
+            i->second.drvPath.c_str(),
+            i->second.outPath.c_str());
+        inputs = ATinsert(inputs, t);
+    }
+
+    ATerm inputs2 = ATmake("List(<term>)", ATreverse(inputs));
+
+    /* Also write a copy of the list of inputs to the store; we need
+       it for future modifications of the environment. */
+    Path inputsFile = writeTerm(inputs2, "-env-inputs");
+
+    Expr topLevel = ATmake(
+        "Call(<term>, Attrs(["
+        "Bind(\"system\", Str(<str>)), "
+        "Bind(\"derivations\", <term>), " // !!! redundant
+        "Bind(\"manifest\", Path(<str>))"
+        "]))",
+        envBuilder, thisSystem.c_str(), inputs2, inputsFile.c_str());
+
+    /* Instantiate it. */
+    debug(format("evaluating builder expression `%1%'") % topLevel);
+    DrvInfo topLevelDrv;
+    if (!parseDerivation(state, topLevel, topLevelDrv))
+        abort();
+    
+    /* Realise the resulting store expression. */
+    debug(format("realising user environment"));
+    Path nfPath = normaliseStoreExpr(topLevelDrv.drvPath);
+    realiseClosure(nfPath);
+
+    /* Switch the current user environment to the output path. */
+    debug(format("switching to new user environment"));
+    Path linkPath = createLink(topLevelDrv.outPath, topLevelDrv.drvPath);
+//     switchLink(current"), link);
+}
+
+
+static void opInstall(EvalState & state,
+    Strings opFlags, Strings opArgs)
+{
+    if (opArgs.size() < 1) throw UsageError("Nix expression expected");
+
+    Path nePath = opArgs.front();
+    opArgs.pop_front();
+
+    installDerivations(state, nePath,
+        Strings(opArgs.begin(), opArgs.end()));
+}
+
+
+static void opQuery(EvalState & state,
+    Strings opFlags, Strings opArgs)
+{
+    enum { qName } query = qName;
+    enum { sInstalled, sAvailable } source = sInstalled;
+
+    for (Strings::iterator i = opFlags.begin();
+         i != opFlags.end(); ++i)
+        if (*i == "--name") query = qName;
+        else if (*i == "--installed") source = sInstalled;
+        else if (*i == "--available" || *i == "-f") source = sAvailable;
+        else throw UsageError(format("unknown flag `%1%'") % *i);
+
+    /* Obtain derivation information from the specified source. */
+    DrvInfos drvs;
+
+    switch (source) {
+
+        case sInstalled:
+            break;
+
+        case sAvailable: {
+            Path nePath = opArgs.front();
+            opArgs.pop_front();
+            loadDerivations(state, nePath, drvs);
+            break;
+        }
+
+        default: abort();
+    }
+
+    /* Perform the specified query on the derivations. */
+    switch (query) {
+
+        case qName: {
+            if (opArgs.size() != 0) throw UsageError("no arguments expected");
+            for (DrvInfos::iterator i = drvs.begin(); i != drvs.end(); ++i)
+                cout << format("%1%\n") % i->second.name;
+            break;
+        }
+        
+        default: abort();
+    }
+}
+
+
+void run(Strings args)
+{
+    EvalState state;
+    Strings opFlags, opArgs;
+    Operation op = 0;
+
+    for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
+        string arg = *i;
+
+        Operation oldOp = op;
+
+        if (arg == "--install" || arg == "-i")
+            op = opInstall;
+        if (arg == "--query" || arg == "-q")
+            op = opQuery;
+        else if (arg == "--verbose" || arg == "-v")
+            verbosity = (Verbosity) ((int) verbosity + 1);
+        else if (arg[0] == '-')
+            opFlags.push_back(arg);
+        else
+            opArgs.push_back(arg);
+
+        if (oldOp && oldOp != op)
+            throw UsageError("only one operation may be specified");
+    }
+
+    if (!op) throw UsageError("no operation specified");
+
+    openDB();
+
+    op(state, opFlags, opArgs);
+
+    printEvalStats(state);
+}
+
+
+string programId = "nix-env";