lix/src/nix-instantiate/main.cc
Eelco Dolstra 630ae0c9d7 * nix-build: use an indirection scheme to make it easier for users to
get rid of GC roots.  Nix-build places a symlink `result' in the
  current directory.  Previously, removing that symlink would not
  remove the store path being linked to as a GC root.  Now, the GC
  root created by nix-build is actually a symlink in
  `/nix/var/nix/gcroots/auto' to `result'.  So if that symlink is
  removed the GC root automatically becomes invalid (since it can no
  longer be resolved).  The root itself is not automatically removed -
  the garbage collector should delete dangling roots.
2005-02-01 13:48:46 +00:00

144 lines
3.6 KiB
C++

#include <map>
#include <iostream>
#include "globals.hh"
#include "build.hh"
#include "gc.hh"
#include "shared.hh"
#include "eval.hh"
#include "parser.hh"
#include "nixexpr-ast.hh"
#include "help.txt.hh"
void printHelp()
{
cout << string((char *) helpText, sizeof helpText);
}
static Expr evalStdin(EvalState & state, bool parseOnly)
{
startNest(nest, lvlTalkative, format("evaluating standard input"));
string s, s2;
while (getline(cin, s2)) s += s2 + "\n";
Expr e = parseExprFromString(state, s, absPath("."));
return parseOnly ? e : evalExpr(state, e);
}
static Path gcRoot;
static int rootNr = 0;
static bool indirectRoot = false;
/* Print out the paths of the resulting derivation(s). If the user
specified the `--add-root' flag, we register the derivation as a
garbage collection root and print out the path of the GC root
symlink instead. */
static void printDrvPaths(EvalState & state, Expr e)
{
ATermList es;
/* !!! duplication w.r.t. parseDerivations in nix-env */
if (matchAttrs(e, es)) {
Expr a = queryAttr(e, "type");
if (a && evalString(state, a) == "derivation") {
a = queryAttr(e, "drvPath");
if (a) {
Path drvPath = evalPath(state, a);
if (gcRoot == "")
printGCWarning();
else
drvPath = addPermRoot(drvPath,
makeRootName(gcRoot, rootNr),
indirectRoot);
cout << format("%1%\n") % drvPath;
return;
}
throw Error("bad derivation");
} else {
ATermMap drvMap;
queryAllAttrs(e, drvMap);
for (ATermIterator i(drvMap.keys()); i; ++i)
printDrvPaths(state, evalExpr(state, drvMap.get(*i)));
return;
}
}
if (matchList(e, es)) {
for (ATermIterator i(es); i; ++i)
printDrvPaths(state, evalExpr(state, *i));
return;
}
throw Error("expression does not evaluate to one or more derivations");
}
static void printResult(EvalState & state, Expr e, bool evalOnly)
{
if (evalOnly)
cout << format("%1%\n") % e;
else
printDrvPaths(state, e);
}
void run(Strings args)
{
EvalState state;
Strings files;
bool readStdin = false;
bool evalOnly = false;
bool parseOnly = false;
for (Strings::iterator i = args.begin();
i != args.end(); )
{
string arg = *i++;
if (arg == "-")
readStdin = true;
else if (arg == "--eval-only") {
readOnlyMode = true;
evalOnly = true;
}
else if (arg == "--parse-only") {
readOnlyMode = true;
parseOnly = evalOnly = true;
}
else if (arg == "--add-root") {
if (i == args.end())
throw UsageError("`--add-root requires an argument");
gcRoot = absPath(*i++);
}
else if (arg == "--indirect")
indirectRoot = true;
else if (arg[0] == '-')
throw UsageError(format("unknown flag `%1%`") % arg);
else
files.push_back(arg);
}
openDB();
if (readStdin) {
Expr e = evalStdin(state, parseOnly);
printResult(state, e, evalOnly);
}
for (Strings::iterator i = files.begin();
i != files.end(); i++)
{
Expr e = evalFile(state, absPath(*i));
/* !!! parseOnly ignored */
printResult(state, e, evalOnly);
}
printEvalStats(state);
}
string programId = "nix-instantiate";