lix/src/libexpr/primops.cc
2014-09-23 15:08:27 +02:00

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#include "eval.hh"
#include "misc.hh"
#include "globals.hh"
#include "store-api.hh"
#include "util.hh"
#include "archive.hh"
#include "value-to-xml.hh"
#include "value-to-json.hh"
#include "json-to-value.hh"
#include "names.hh"
#include "eval-inline.hh"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <algorithm>
#include <cstring>
#include <dlfcn.h>
namespace nix {
/*************************************************************
* Miscellaneous
*************************************************************/
/* Decode a context string !<name>!<path> into a pair <path,
name>. */
std::pair<string, string> decodeContext(const string & s)
{
if (s.at(0) == '!') {
size_t index = s.find("!", 1);
return std::pair<string, string>(string(s, index + 1), string(s, 1, index - 1));
} else
return std::pair<string, string>(s, "");
}
struct InvalidPathError : EvalError
{
Path path;
InvalidPathError(const Path & path) :
EvalError(format("path %1% is not valid") % path), path(path) {};
~InvalidPathError() throw () { };
};
static void realiseContext(const PathSet & context)
{
PathSet drvs;
for (auto & i : context) {
std::pair<string, string> decoded = decodeContext(i);
Path ctx = decoded.first;
assert(isStorePath(ctx));
if (!store->isValidPath(ctx))
throw InvalidPathError(ctx);
if (isDerivation(ctx))
drvs.insert(decoded.first + "!" + decoded.second);
}
if (!drvs.empty()) {
/* For performance, prefetch all substitute info. */
PathSet willBuild, willSubstitute, unknown;
unsigned long long downloadSize, narSize;
queryMissing(*store, drvs,
willBuild, willSubstitute, unknown, downloadSize, narSize);
store->buildPaths(drvs);
}
}
/* Load and evaluate an expression from path specified by the
argument. */
static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[1], context);
try {
realiseContext(context);
} catch (InvalidPathError & e) {
throw EvalError(format("cannot import %1%, since path %2% is not valid, at %3%")
% path % e.path % pos);
}
if (isStorePath(path) && store->isValidPath(path) && isDerivation(path)) {
Derivation drv = readDerivation(path);
Value & w = *state.allocValue();
state.mkAttrs(w, 2 + drv.outputs.size());
mkString(*state.allocAttr(w, state.sDrvPath), path, singleton<PathSet>("=" + path));
state.mkList(*state.allocAttr(w, state.symbols.create("outputs")), drv.outputs.size());
unsigned int outputs_index = 0;
Value * outputsVal = w.attrs->find(state.symbols.create("outputs"))->value;
foreach (DerivationOutputs::iterator, i, drv.outputs) {
mkString(*state.allocAttr(w, state.symbols.create(i->first)),
i->second.path, singleton<PathSet>("!" + i->first + "!" + path));
mkString(*(outputsVal->list.elems[outputs_index++] = state.allocValue()),
i->first);
}
w.attrs->sort();
Value fun;
state.evalFile(state.findFile("nix/imported-drv-to-derivation.nix"), fun);
state.forceFunction(fun, pos);
mkApp(v, fun, w);
state.forceAttrs(v, pos);
} else {
state.forceAttrs(*args[0]);
if (args[0]->attrs->empty())
state.evalFile(path, v);
else {
Env * env = &state.allocEnv(args[0]->attrs->size());
env->up = &state.baseEnv;
StaticEnv staticEnv(false, &state.staticBaseEnv);
unsigned int displ = 0;
for (auto & attr : *args[0]->attrs) {
staticEnv.vars[attr.name] = displ;
env->values[displ++] = attr.value;
}
startNest(nest, lvlTalkative, format("evaluating file %1%") % path);
Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
e->eval(state, *env, v);
}
}
}
/* Want reasonable symbol names, so extern C */
/* !!! Should we pass the Pos or the file name too? */
extern "C" typedef void (*ValueInitializer)(EvalState & state, Value & v);
/* Load a ValueInitializer from a dso and return whatever it initializes */
static void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[0], context);
try {
realiseContext(context);
} catch (InvalidPathError & e) {
throw EvalError(format("cannot import %1%, since path %2% is not valid, at %3%")
% path % e.path % pos);
}
string sym = state.forceStringNoCtx(*args[1], pos);
void *handle = dlopen(path.c_str(), RTLD_LAZY | RTLD_LOCAL);
if (!handle)
throw EvalError(format("could not open %1%: %2%") % path % dlerror());
dlerror();
ValueInitializer func = (ValueInitializer) dlsym(handle, sym.c_str());
if(!func) {
char *message = dlerror();
if (message)
throw EvalError(format("could not load symbol %1% from %2%: %3%") % sym % path % message);
else
throw EvalError(format("symbol %1% from %2% resolved to NULL when a function pointer was expected")
% sym % path);
}
(func)(state, v);
/* We don't dlclose because v may be a primop referencing a function in the shared object file */
}
/* Return a string representing the type of the expression. */
static void prim_typeOf(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
string t;
switch (args[0]->type) {
case tInt: t = "int"; break;
case tBool: t = "bool"; break;
case tString: t = "string"; break;
case tPath: t = "path"; break;
case tNull: t = "null"; break;
case tAttrs: t = "set"; break;
case tList: t = "list"; break;
case tLambda:
case tPrimOp:
case tPrimOpApp:
t = "lambda";
break;
default: abort();
}
mkString(v, state.symbols.create(t));
}
/* Determine whether the argument is the null value. */
static void prim_isNull(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tNull);
}
/* Determine whether the argument is a function. */
static void prim_isFunction(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tLambda);
}
/* Determine whether the argument is an integer. */
static void prim_isInt(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tInt);
}
/* Determine whether the argument is a string. */
static void prim_isString(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tString);
}
/* Determine whether the argument is a Boolean. */
static void prim_isBool(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tBool);
}
struct CompareValues
{
bool operator () (const Value * v1, const Value * v2) const
{
if (v1->type != v2->type)
throw EvalError("cannot compare values of different types");
switch (v1->type) {
case tInt:
return v1->integer < v2->integer;
case tString:
return strcmp(v1->string.s, v2->string.s) < 0;
case tPath:
return strcmp(v1->path, v2->path) < 0;
default:
throw EvalError(format("cannot compare %1% with %2%") % showType(*v1) % showType(*v2));
}
}
};
#if HAVE_BOEHMGC
typedef list<Value *, gc_allocator<Value *> > ValueList;
#else
typedef list<Value *> ValueList;
#endif
static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
startNest(nest, lvlDebug, "finding dependencies");
state.forceAttrs(*args[0], pos);
/* Get the start set. */
Bindings::iterator startSet =
args[0]->attrs->find(state.symbols.create("startSet"));
if (startSet == args[0]->attrs->end())
throw EvalError(format("attribute startSet required, at %1%") % pos);
state.forceList(*startSet->value, pos);
ValueList workSet;
for (unsigned int n = 0; n < startSet->value->list.length; ++n)
workSet.push_back(startSet->value->list.elems[n]);
/* Get the operator. */
Bindings::iterator op =
args[0]->attrs->find(state.symbols.create("operator"));
if (op == args[0]->attrs->end())
throw EvalError(format("attribute operator required, at %1%") % pos);
state.forceValue(*op->value);
/* Construct the closure by applying the operator to element of
`workSet', adding the result to `workSet', continuing until
no new elements are found. */
ValueList res;
// `doneKeys' doesn't need to be a GC root, because its values are
// reachable from res.
set<Value *, CompareValues> doneKeys;
while (!workSet.empty()) {
Value * e = *(workSet.begin());
workSet.pop_front();
state.forceAttrs(*e, pos);
Bindings::iterator key =
e->attrs->find(state.symbols.create("key"));
if (key == e->attrs->end())
throw EvalError(format("attribute key required, at %1%") % pos);
state.forceValue(*key->value);
if (doneKeys.find(key->value) != doneKeys.end()) continue;
doneKeys.insert(key->value);
res.push_back(e);
/* Call the `operator' function with `e' as argument. */
Value call;
mkApp(call, *op->value, *e);
state.forceList(call, pos);
/* Add the values returned by the operator to the work set. */
for (unsigned int n = 0; n < call.list.length; ++n) {
state.forceValue(*call.list.elems[n]);
workSet.push_back(call.list.elems[n]);
}
}
/* Create the result list. */
state.mkList(v, res.size());
unsigned int n = 0;
foreach (ValueList::iterator, i, res)
v.list.elems[n++] = *i;
}
static void prim_abort(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context);
throw Abort(format("evaluation aborted with the following error message: %1%") % s);
}
static void prim_throw(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context);
throw ThrownError(s);
}
static void prim_addErrorContext(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
try {
state.forceValue(*args[1]);
v = *args[1];
} catch (Error & e) {
PathSet context;
e.addPrefix(format("%1%\n") % state.coerceToString(pos, *args[0], context));
throw;
}
}
/* Try evaluating the argument. Success => {success=true; value=something;},
* else => {success=false; value=false;} */
static void prim_tryEval(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.mkAttrs(v, 2);
try {
state.forceValue(*args[0]);
v.attrs->push_back(Attr(state.sValue, args[0]));
mkBool(*state.allocAttr(v, state.symbols.create("success")), true);
} catch (AssertionError & e) {
mkBool(*state.allocAttr(v, state.sValue), false);
mkBool(*state.allocAttr(v, state.symbols.create("success")), false);
}
v.attrs->sort();
}
/* Return an environment variable. Use with care. */
static void prim_getEnv(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string name = state.forceStringNoCtx(*args[0], pos);
mkString(v, getEnv(name));
}
/* Evaluate the first argument, then return the second argument. */
static void prim_seq(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
state.forceValue(*args[1]);
v = *args[1];
}
/* Evaluate the first argument deeply (i.e. recursing into lists and
attrsets), then return the second argument. */
static void prim_deepSeq(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValueDeep(*args[0]);
state.forceValue(*args[1]);
v = *args[1];
}
/* Evaluate the first expression and print it on standard error. Then
return the second expression. Useful for debugging. */
static void prim_trace(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
if (args[0]->type == tString)
printMsg(lvlError, format("trace: %1%") % args[0]->string.s);
else
printMsg(lvlError, format("trace: %1%") % *args[0]);
state.forceValue(*args[1]);
v = *args[1];
}
#if HAVE_BOEHMGC
void canaryFinalizer(GC_PTR obj, GC_PTR client_data)
{
Value * v = (Value *) obj;
EvalState & state(* (EvalState *) client_data);
printMsg(lvlError, format("canary %1% garbage-collected") % v->string.s);
auto i = state.gcCanaries.find(v);
assert(i != state.gcCanaries.end());
state.gcCanaries.erase(i);
}
#endif
void prim_gcCanary(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string s = state.forceStringNoCtx(*args[0], pos);
state.mkList(v, 1);
Value * canary = v.list.elems[0] = state.allocValue();
#if HAVE_BOEHMGC
state.gcCanaries.insert(canary);
GC_register_finalizer(canary, canaryFinalizer, &state, 0, 0);
#endif
mkString(*canary, s);
}
void prim_valueSize(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
/* We're not forcing the argument on purpose. */
mkInt(v, valueSize(*args[0]));
}
/*************************************************************
* Derivations
*************************************************************/
/* Construct (as a unobservable side effect) a Nix derivation
expression that performs the derivation described by the argument
set. Returns the original set extended with the following
attributes: `outPath' containing the primary output path of the
derivation; `drvPath' containing the path of the Nix expression;
and `type' set to `derivation' to indicate that this is a
derivation. */
static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
startNest(nest, lvlVomit, "evaluating derivation");
state.forceAttrs(*args[0], pos);
/* Figure out the name first (for stack backtraces). */
Bindings::iterator attr = args[0]->attrs->find(state.sName);
if (attr == args[0]->attrs->end())
throw EvalError(format("required attribute name missing, at %1%") % pos);
string drvName;
Pos & posDrvName(*attr->pos);
try {
drvName = state.forceStringNoCtx(*attr->value, pos);
} catch (Error & e) {
e.addPrefix(format("while evaluating the derivation attribute name at %1%:\n") % posDrvName);
throw;
}
/* Check whether null attributes should be ignored. */
bool ignoreNulls = false;
attr = args[0]->attrs->find(state.sIgnoreNulls);
if (attr != args[0]->attrs->end())
ignoreNulls = state.forceBool(*attr->value);
/* Build the derivation expression by processing the attributes. */
Derivation drv;
PathSet context;
string outputHash, outputHashAlgo;
bool outputHashRecursive = false;
StringSet outputs;
outputs.insert("out");
foreach (Bindings::iterator, i, *args[0]->attrs) {
if (i->name == state.sIgnoreNulls) continue;
string key = i->name;
startNest(nest, lvlVomit, format("processing attribute %1%") % key);
try {
if (ignoreNulls) {
state.forceValue(*i->value);
if (i->value->type == tNull) continue;
}
/* The `args' attribute is special: it supplies the
command-line arguments to the builder. */
if (key == "args") {
state.forceList(*i->value, pos);
for (unsigned int n = 0; n < i->value->list.length; ++n) {
string s = state.coerceToString(posDrvName, *i->value->list.elems[n], context, true);
drv.args.push_back(s);
}
}
/* All other attributes are passed to the builder through
the environment. */
else {
string s = state.coerceToString(posDrvName, *i->value, context, true);
drv.env[key] = s;
if (key == "builder") drv.builder = s;
else if (i->name == state.sSystem) drv.platform = s;
else if (i->name == state.sName) {
drvName = s;
printMsg(lvlVomit, format("derivation name is %1%") % drvName);
}
else if (key == "outputHash") outputHash = s;
else if (key == "outputHashAlgo") outputHashAlgo = s;
else if (key == "outputHashMode") {
if (s == "recursive") outputHashRecursive = true;
else if (s == "flat") outputHashRecursive = false;
else throw EvalError(format("invalid value %1% for outputHashMode attribute, at %2%") % s % posDrvName);
}
else if (key == "outputs") {
Strings tmp = tokenizeString<Strings>(s);
outputs.clear();
foreach (Strings::iterator, j, tmp) {
if (outputs.find(*j) != outputs.end())
throw EvalError(format("duplicate derivation output %1%, at %2%") % *j % posDrvName);
/* !!! Check whether *j is a valid attribute
name. */
/* Derivations cannot be named drv, because
then we'd have an attribute drvPath in
the resulting set. */
if (*j == "drv")
throw EvalError(format("invalid derivation output name drv, at %1%") % posDrvName);
outputs.insert(*j);
}
if (outputs.empty())
throw EvalError(format("derivation cannot have an empty set of outputs, at %1%") % posDrvName);
}
}
} catch (Error & e) {
e.addPrefix(format("while evaluating the attribute %1% of the derivation %2% at %3%:\n")
% key % drvName % posDrvName);
throw;
}
}
/* Everything in the context of the strings in the derivation
attributes should be added as dependencies of the resulting
derivation. */
foreach (PathSet::iterator, i, context) {
Path path = *i;
/* Paths marked with `=' denote that the path of a derivation
is explicitly passed to the builder. Since that allows the
builder to gain access to every path in the dependency
graph of the derivation (including all outputs), all paths
in the graph must be added to this derivation's list of
inputs to ensure that they are available when the builder
runs. */
if (path.at(0) == '=') {
/* !!! This doesn't work if readOnlyMode is set. */
PathSet refs; computeFSClosure(*store, string(path, 1), refs);
foreach (PathSet::iterator, j, refs) {
drv.inputSrcs.insert(*j);
if (isDerivation(*j))
drv.inputDrvs[*j] = store->queryDerivationOutputNames(*j);
}
}
/* See prim_unsafeDiscardOutputDependency. */
else if (path.at(0) == '~')
drv.inputSrcs.insert(string(path, 1));
/* Handle derivation outputs of the form !<name>!<path>. */
else if (path.at(0) == '!') {
std::pair<string, string> ctx = decodeContext(path);
drv.inputDrvs[ctx.first].insert(ctx.second);
}
/* Handle derivation contexts returned by
builtins.storePath. */
else if (isDerivation(path))
drv.inputDrvs[path] = store->queryDerivationOutputNames(path);
/* Otherwise it's a source file. */
else
drv.inputSrcs.insert(path);
}
/* Do we have all required attributes? */
if (drv.builder == "")
throw EvalError(format("required attribute builder missing, at %1%") % posDrvName);
if (drv.platform == "")
throw EvalError(format("required attribute system missing, at %1%") % posDrvName);
/* Check whether the derivation name is valid. */
checkStoreName(drvName);
if (isDerivation(drvName))
throw EvalError(format("derivation names are not allowed to end in %1%, at %2%")
% drvExtension % posDrvName);
if (outputHash != "") {
/* Handle fixed-output derivations. */
if (outputs.size() != 1 || *(outputs.begin()) != "out")
throw Error(format("multiple outputs are not supported in fixed-output derivations, at %1%") % posDrvName);
HashType ht = parseHashType(outputHashAlgo);
if (ht == htUnknown)
throw EvalError(format("unknown hash algorithm %1%, at %2%") % outputHashAlgo % posDrvName);
Hash h = parseHash16or32(ht, outputHash);
outputHash = printHash(h);
if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo;
Path outPath = makeFixedOutputPath(outputHashRecursive, ht, h, drvName);
drv.env["out"] = outPath;
drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, outputHash);
}
else {
/* Construct the "masked" store derivation, which is the final
one except that in the list of outputs, the output paths
are empty, and the corresponding environment variables have
an empty value. This ensures that changes in the set of
output names do get reflected in the hash. */
foreach (StringSet::iterator, i, outputs) {
drv.env[*i] = "";
drv.outputs[*i] = DerivationOutput("", "", "");
}
/* Use the masked derivation expression to compute the output
path. */
Hash h = hashDerivationModulo(*store, drv);
foreach (DerivationOutputs::iterator, i, drv.outputs)
if (i->second.path == "") {
Path outPath = makeOutputPath(i->first, h, drvName);
drv.env[i->first] = outPath;
i->second.path = outPath;
}
}
/* Write the resulting term into the Nix store directory. */
Path drvPath = writeDerivation(*store, drv, drvName, state.repair);
printMsg(lvlChatty, format("instantiated %1% -> %2%")
% drvName % drvPath);
/* Optimisation, but required in read-only mode! because in that
case we don't actually write store derivations, so we can't
read them later. */
drvHashes[drvPath] = hashDerivationModulo(*store, drv);
state.mkAttrs(v, 1 + drv.outputs.size());
mkString(*state.allocAttr(v, state.sDrvPath), drvPath, singleton<PathSet>("=" + drvPath));
foreach (DerivationOutputs::iterator, i, drv.outputs) {
mkString(*state.allocAttr(v, state.symbols.create(i->first)),
i->second.path, singleton<PathSet>("!" + i->first + "!" + drvPath));
}
v.attrs->sort();
}
/*************************************************************
* Paths
*************************************************************/
/* Convert the argument to a path. !!! obsolete? */
static void prim_toPath(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[0], context);
mkString(v, canonPath(path), context);
}
/* Allow a valid store path to be used in an expression. This is
useful in some generated expressions such as in nix-push, which
generates a call to a function with an already existing store path
as argument. You don't want to use `toPath' here because it copies
the path to the Nix store, which yields a copy like
/nix/store/newhash-oldhash-oldname. In the past, `toPath' had
special case behaviour for store paths, but that created weird
corner cases. */
static void prim_storePath(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[0], context);
/* Resolve symlinks in path, unless path itself is a symlink
directly in the store. The latter condition is necessary so
e.g. nix-push does the right thing. */
if (!isStorePath(path)) path = canonPath(path, true);
if (!isInStore(path))
throw EvalError(format("path %1% is not in the Nix store, at %2%") % path % pos);
Path path2 = toStorePath(path);
if (!settings.readOnlyMode)
store->ensurePath(path2);
context.insert(path2);
mkString(v, path, context);
}
static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[0], context);
if (!context.empty())
throw EvalError(format("string %1% cannot refer to other paths, at %2%") % path % pos);
mkBool(v, pathExists(path));
}
/* Return the base name of the given string, i.e., everything
following the last slash. */
static void prim_baseNameOf(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
mkString(v, baseNameOf(state.coerceToString(pos, *args[0], context)), context);
}
/* Return the directory of the given path, i.e., everything before the
last slash. Return either a path or a string depending on the type
of the argument. */
static void prim_dirOf(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path dir = dirOf(state.coerceToPath(pos, *args[0], context));
if (args[0]->type == tPath) mkPath(v, dir.c_str()); else mkString(v, dir, context);
}
/* Return the contents of a file as a string. */
static void prim_readFile(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[0], context);
if (!context.empty())
throw EvalError(format("string %1% cannot refer to other paths, at %2%") % path % pos);
mkString(v, readFile(path).c_str());
}
/* Find a file in the Nix search path. Used to implement <x> paths,
which are desugared to findFile __nixPath "x". */
static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceList(*args[0], pos);
SearchPath searchPath;
PathSet context;
for (unsigned int n = 0; n < args[0]->list.length; ++n) {
Value & v2(*args[0]->list.elems[n]);
state.forceAttrs(v2, pos);
string prefix;
Bindings::iterator i = v2.attrs->find(state.symbols.create("prefix"));
if (i != v2.attrs->end())
prefix = state.forceStringNoCtx(*i->value, pos);
i = v2.attrs->find(state.symbols.create("path"));
if (i == v2.attrs->end())
throw EvalError(format("attribute path missing, at %1%") % pos);
string path = state.coerceToPath(pos, *i->value, context);
searchPath.push_back(std::pair<string, Path>(prefix, path));
}
string path = state.forceStringNoCtx(*args[1], pos);
try {
realiseContext(context);
} catch (InvalidPathError & e) {
throw EvalError(format("cannot find %1%, since path %2% is not valid, at %3%")
% path % e.path % pos);
}
mkPath(v, state.findFile(searchPath, path).c_str());
}
/*************************************************************
* Creating files
*************************************************************/
/* Convert the argument (which can be any Nix expression) to an XML
representation returned in a string. Not all Nix expressions can
be sensibly or completely represented (e.g., functions). */
static void prim_toXML(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
std::ostringstream out;
PathSet context;
printValueAsXML(state, true, false, *args[0], out, context);
mkString(v, out.str(), context);
}
/* Convert the argument (which can be any Nix expression) to a JSON
string. Not all Nix expressions can be sensibly or completely
represented (e.g., functions). */
static void prim_toJSON(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
std::ostringstream out;
PathSet context;
printValueAsJSON(state, true, *args[0], out, context);
mkString(v, out.str(), context);
}
/* Parse a JSON string to a value. */
static void prim_fromJSON(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string s = state.forceStringNoCtx(*args[0], pos);
parseJSON(state, s, v);
}
/* Store a string in the Nix store as a source file that can be used
as an input by derivations. */
static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string name = state.forceStringNoCtx(*args[0], pos);
string contents = state.forceString(*args[1], context);
PathSet refs;
foreach (PathSet::iterator, i, context) {
Path path = *i;
if (path.at(0) == '=') path = string(path, 1);
if (isDerivation(path))
throw EvalError(format("in toFile: the file %1% cannot refer to derivation outputs, at %2%") % name % pos);
refs.insert(path);
}
Path storePath = settings.readOnlyMode
? computeStorePathForText(name, contents, refs)
: store->addTextToStore(name, contents, refs, state.repair);
/* Note: we don't need to add `context' to the context of the
result, since `storePath' itself has references to the paths
used in args[1]. */
mkString(v, storePath, singleton<PathSet>(storePath));
}
struct FilterFromExpr : PathFilter
{
EvalState & state;
Value & filter;
FilterFromExpr(EvalState & state, Value & filter)
: state(state), filter(filter)
{
}
bool operator () (const Path & path)
{
struct stat st;
if (lstat(path.c_str(), &st))
throw SysError(format("getting attributes of path %1%") % path);
/* Call the filter function. The first argument is the path,
the second is a string indicating the type of the file. */
Value arg1;
mkString(arg1, path);
Value fun2;
state.callFunction(filter, arg1, fun2, noPos);
Value arg2;
mkString(arg2,
S_ISREG(st.st_mode) ? "regular" :
S_ISDIR(st.st_mode) ? "directory" :
S_ISLNK(st.st_mode) ? "symlink" :
"unknown" /* not supported, will fail! */);
Value res;
state.callFunction(fun2, arg2, res, noPos);
return state.forceBool(res);
}
};
static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
Path path = state.coerceToPath(pos, *args[1], context);
if (!context.empty())
throw EvalError(format("string %1% cannot refer to other paths, at %2%") % path % pos);
state.forceValue(*args[0]);
if (args[0]->type != tLambda)
throw TypeError(format("first argument in call to filterSource is not a function but %1%, at %2%") % showType(*args[0]) % pos);
FilterFromExpr filter(state, *args[0]);
Path dstPath = settings.readOnlyMode
? computeStorePathForPath(path, true, htSHA256, filter).first
: store->addToStore(path, true, htSHA256, filter, state.repair);
mkString(v, dstPath, singleton<PathSet>(dstPath));
}
/*************************************************************
* Sets
*************************************************************/
/* Return the names of the attributes in a set as a sorted list of
strings. */
static void prim_attrNames(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceAttrs(*args[0], pos);
state.mkList(v, args[0]->attrs->size());
unsigned int n = 0;
for (auto & i : *args[0]->attrs)
mkString(*(v.list.elems[n++] = state.allocValue()), i.name);
std::sort(v.list.elems, v.list.elems + n, [](Value * v1, Value * v2) { return strcmp(v1->string.s, v2->string.s) < 0; });
}
/* Dynamic version of the `.' operator. */
void prim_getAttr(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string attr = state.forceStringNoCtx(*args[0], pos);
state.forceAttrs(*args[1], pos);
// !!! Should we create a symbol here or just do a lookup?
Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr));
if (i == args[1]->attrs->end())
throw EvalError(format("attribute %1% missing, at %2%") % attr % pos);
// !!! add to stack trace?
if (state.countCalls && i->pos) state.attrSelects[*i->pos]++;
state.forceValue(*i->value);
v = *i->value;
}
/* Return position information of the specified attribute. */
void prim_unsafeGetAttrPos(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string attr = state.forceStringNoCtx(*args[0], pos);
state.forceAttrs(*args[1], pos);
Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr));
if (i == args[1]->attrs->end())
mkNull(v);
else
state.mkPos(v, i->pos);
}
/* Dynamic version of the `?' operator. */
static void prim_hasAttr(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string attr = state.forceStringNoCtx(*args[0], pos);
state.forceAttrs(*args[1], pos);
mkBool(v, args[1]->attrs->find(state.symbols.create(attr)) != args[1]->attrs->end());
}
/* Determine whether the argument is a set. */
static void prim_isAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tAttrs);
}
static void prim_removeAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceAttrs(*args[0], pos);
state.forceList(*args[1], pos);
/* Get the attribute names to be removed. */
std::set<Symbol> names;
for (unsigned int i = 0; i < args[1]->list.length; ++i) {
state.forceStringNoCtx(*args[1]->list.elems[i], pos);
names.insert(state.symbols.create(args[1]->list.elems[i]->string.s));
}
/* Copy all attributes not in that set. Note that we don't need
to sort v.attrs because it's a subset of an already sorted
vector. */
state.mkAttrs(v, args[0]->attrs->size());
foreach (Bindings::iterator, i, *args[0]->attrs) {
if (names.find(i->name) == names.end())
v.attrs->push_back(*i);
}
}
/* Builds a set from a list specifying (name, value) pairs. To be
precise, a list [{name = "name1"; value = value1;} ... {name =
"nameN"; value = valueN;}] is transformed to {name1 = value1;
... nameN = valueN;}. In case of duplicate occurences of the same
name, the first takes precedence. */
static void prim_listToAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceList(*args[0], pos);
state.mkAttrs(v, args[0]->list.length);
std::set<Symbol> seen;
for (unsigned int i = 0; i < args[0]->list.length; ++i) {
Value & v2(*args[0]->list.elems[i]);
state.forceAttrs(v2, pos);
Bindings::iterator j = v2.attrs->find(state.sName);
if (j == v2.attrs->end())
throw TypeError(format("name attribute missing in a call to listToAttrs, at %1%") % pos);
string name = state.forceStringNoCtx(*j->value, pos);
Symbol sym = state.symbols.create(name);
if (seen.find(sym) == seen.end()) {
Bindings::iterator j2 = v2.attrs->find(state.symbols.create(state.sValue));
if (j2 == v2.attrs->end())
throw TypeError(format("value attribute missing in a call to listToAttrs, at %1%") % pos);
v.attrs->push_back(Attr(sym, j2->value, j2->pos));
seen.insert(sym);
}
}
v.attrs->sort();
}
/* Return the right-biased intersection of two sets as1 and as2,
i.e. a set that contains every attribute from as2 that is also a
member of as1. */
static void prim_intersectAttrs(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceAttrs(*args[0], pos);
state.forceAttrs(*args[1], pos);
state.mkAttrs(v, std::min(args[0]->attrs->size(), args[1]->attrs->size()));
foreach (Bindings::iterator, i, *args[0]->attrs) {
Bindings::iterator j = args[1]->attrs->find(i->name);
if (j != args[1]->attrs->end())
v.attrs->push_back(*j);
}
}
/* Return a set containing the names of the formal arguments expected
by the function `f'. The value of each attribute is a Boolean
denoting whether has a default value. For instance,
functionArgs ({ x, y ? 123}: ...)
=> { x = false; y = true; }
"Formal argument" here refers to the attributes pattern-matched by
the function. Plain lambdas are not included, e.g.
functionArgs (x: ...)
=> { }
*/
static void prim_functionArgs(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
if (args[0]->type != tLambda)
throw TypeError(format("functionArgs requires a function, at %1%") % pos);
if (!args[0]->lambda.fun->matchAttrs) {
state.mkAttrs(v, 0);
return;
}
state.mkAttrs(v, args[0]->lambda.fun->formals->formals.size());
foreach (Formals::Formals_::iterator, i, args[0]->lambda.fun->formals->formals)
// !!! should optimise booleans (allocate only once)
mkBool(*state.allocAttr(v, i->name), i->def);
v.attrs->sort();
}
/*************************************************************
* Lists
*************************************************************/
/* Determine whether the argument is a list. */
static void prim_isList(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
mkBool(v, args[0]->type == tList);
}
static void elemAt(EvalState & state, const Pos & pos, Value & list, int n, Value & v)
{
state.forceList(list, pos);
if (n < 0 || (unsigned int) n >= list.list.length)
throw Error(format("list index %1% is out of bounds, at %2%") % n % pos);
state.forceValue(*list.list.elems[n]);
v = *list.list.elems[n];
}
/* Return the n-1'th element of a list. */
static void prim_elemAt(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
elemAt(state, pos, *args[0], state.forceInt(*args[1], pos), v);
}
/* Return the first element of a list. */
static void prim_head(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
elemAt(state, pos, *args[0], 0, v);
}
/* Return a list consisting of everything but the the first element of
a list. Warning: this function takes O(n) time, so you probably
don't want to use it! */
static void prim_tail(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceList(*args[0], pos);
if (args[0]->list.length == 0)
throw Error(format("tail called on an empty list, at %1%") % pos);
state.mkList(v, args[0]->list.length - 1);
for (unsigned int n = 0; n < v.list.length; ++n)
v.list.elems[n] = args[0]->list.elems[n + 1];
}
/* Apply a function to every element of a list. */
static void prim_map(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceFunction(*args[0], pos);
state.forceList(*args[1], pos);
state.mkList(v, args[1]->list.length);
for (unsigned int n = 0; n < v.list.length; ++n)
mkApp(*(v.list.elems[n] = state.allocValue()),
*args[0], *args[1]->list.elems[n]);
}
/* Filter a list using a predicate; that is, return a list containing
every element from the list for which the predicate function
returns true. */
static void prim_filter(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceFunction(*args[0], pos);
state.forceList(*args[1], pos);
// FIXME: putting this on the stack is risky.
Value * vs[args[1]->list.length];
unsigned int k = 0;
bool same = true;
for (unsigned int n = 0; n < args[1]->list.length; ++n) {
Value res;
state.callFunction(*args[0], *args[1]->list.elems[n], res, noPos);
if (state.forceBool(res))
vs[k++] = args[1]->list.elems[n];
else
same = false;
}
if (same)
v = *args[1];
else {
state.mkList(v, k);
for (unsigned int n = 0; n < k; ++n) v.list.elems[n] = vs[n];
}
}
/* Return true if a list contains a given element. */
static void prim_elem(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
bool res = false;
state.forceList(*args[1], pos);
for (unsigned int n = 0; n < args[1]->list.length; ++n)
if (state.eqValues(*args[0], *args[1]->list.elems[n])) {
res = true;
break;
}
mkBool(v, res);
}
/* Concatenate a list of lists. */
static void prim_concatLists(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceList(*args[0], pos);
state.concatLists(v, args[0]->list.length, args[0]->list.elems, pos);
}
/* Return the length of a list. This is an O(1) time operation. */
static void prim_length(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceList(*args[0], pos);
mkInt(v, args[0]->list.length);
}
/*************************************************************
* Integer arithmetic
*************************************************************/
static void prim_add(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
mkInt(v, state.forceInt(*args[0], pos) + state.forceInt(*args[1], pos));
}
static void prim_sub(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
mkInt(v, state.forceInt(*args[0], pos) - state.forceInt(*args[1], pos));
}
static void prim_mul(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
mkInt(v, state.forceInt(*args[0], pos) * state.forceInt(*args[1], pos));
}
static void prim_div(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
NixInt i2 = state.forceInt(*args[1], pos);
if (i2 == 0) throw EvalError(format("division by zero, at %1%") % pos);
mkInt(v, state.forceInt(*args[0], pos) / i2);
}
static void prim_lessThan(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.forceValue(*args[0]);
state.forceValue(*args[1]);
CompareValues comp;
mkBool(v, comp(args[0], args[1]));
}
/*************************************************************
* String manipulation
*************************************************************/
/* Convert the argument to a string. Paths are *not* copied to the
store, so `toString /foo/bar' yields `"/foo/bar"', not
`"/nix/store/whatever..."'. */
static void prim_toString(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context, true, false);
mkString(v, s, context);
}
/* `substring start len str' returns the substring of `str' starting
at character position `min(start, stringLength str)' inclusive and
ending at `min(start + len, stringLength str)'. `start' must be
non-negative. */
static void prim_substring(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
int start = state.forceInt(*args[0], pos);
int len = state.forceInt(*args[1], pos);
PathSet context;
string s = state.coerceToString(pos, *args[2], context);
if (start < 0) throw EvalError(format("negative start position in substring, at %1%") % pos);
mkString(v, (unsigned int) start >= s.size() ? "" : string(s, start, len), context);
}
static void prim_stringLength(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context);
mkInt(v, s.size());
}
static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context);
mkString(v, s, PathSet());
}
/* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a
builder without causing the derivation to be built (for instance,
in the derivation that builds NARs in nix-push, when doing
source-only deployment). This primop marks the string context so
that builtins.derivation adds the path to drv.inputSrcs rather than
drv.inputDrvs. */
static void prim_unsafeDiscardOutputDependency(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
PathSet context;
string s = state.coerceToString(pos, *args[0], context);
PathSet context2;
foreach (PathSet::iterator, i, context) {
Path p = *i;
if (p.at(0) == '=') p = "~" + string(p, 1);
context2.insert(p);
}
mkString(v, s, context2);
}
/* Return the cryptographic hash of a string in base-16. */
static void prim_hashString(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string type = state.forceStringNoCtx(*args[0], pos);
HashType ht = parseHashType(type);
if (ht == htUnknown)
throw Error(format("unknown hash type %1%, at %2%") % type % pos);
PathSet context; // discarded
string s = state.forceString(*args[1], context);
mkString(v, printHash(hashString(ht, s)), context);
};
/*************************************************************
* Versions
*************************************************************/
static void prim_parseDrvName(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string name = state.forceStringNoCtx(*args[0], pos);
DrvName parsed(name);
state.mkAttrs(v, 2);
mkString(*state.allocAttr(v, state.sName), parsed.name);
mkString(*state.allocAttr(v, state.symbols.create("version")), parsed.version);
v.attrs->sort();
}
static void prim_compareVersions(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
string version1 = state.forceStringNoCtx(*args[0], pos);
string version2 = state.forceStringNoCtx(*args[1], pos);
mkInt(v, compareVersions(version1, version2));
}
/*************************************************************
* Primop registration
*************************************************************/
void EvalState::createBaseEnv()
{
baseEnv.up = 0;
/* Add global constants such as `true' to the base environment. */
Value v;
/* `builtins' must be first! */
mkAttrs(v, 128);
addConstant("builtins", v);
mkBool(v, true);
addConstant("true", v);
mkBool(v, false);
addConstant("false", v);
mkNull(v);
addConstant("null", v);
mkInt(v, time(0));
addConstant("__currentTime", v);
mkString(v, settings.thisSystem.c_str());
addConstant("__currentSystem", v);
mkString(v, nixVersion.c_str());
addConstant("__nixVersion", v);
/* Language version. This should be increased every time a new
language feature gets added. It's not necessary to increase it
when primops get added, because you can just use `builtins ?
primOp' to check. */
mkInt(v, 3);
addConstant("__langVersion", v);
// Miscellaneous
addPrimOp("scopedImport", 2, prim_scopedImport);
Value * v2 = allocValue();
mkAttrs(*v2, 0);
mkApp(v, *baseEnv.values[baseEnvDispl - 1], *v2);
forceValue(v);
addConstant("import", v);
if (settings.enableImportNative)
addPrimOp("__importNative", 2, prim_importNative);
addPrimOp("__typeOf", 1, prim_typeOf);
addPrimOp("isNull", 1, prim_isNull);
addPrimOp("__isFunction", 1, prim_isFunction);
addPrimOp("__isString", 1, prim_isString);
addPrimOp("__isInt", 1, prim_isInt);
addPrimOp("__isBool", 1, prim_isBool);
addPrimOp("__genericClosure", 1, prim_genericClosure);
addPrimOp("abort", 1, prim_abort);
addPrimOp("throw", 1, prim_throw);
addPrimOp("__addErrorContext", 2, prim_addErrorContext);
addPrimOp("__tryEval", 1, prim_tryEval);
addPrimOp("__getEnv", 1, prim_getEnv);
// Strictness
addPrimOp("__seq", 2, prim_seq);
addPrimOp("__deepSeq", 2, prim_deepSeq);
// Debugging
addPrimOp("__trace", 2, prim_trace);
addPrimOp("__gcCanary", 1, prim_gcCanary);
addPrimOp("__valueSize", 1, prim_valueSize);
// Paths
addPrimOp("__toPath", 1, prim_toPath);
addPrimOp("__storePath", 1, prim_storePath);
addPrimOp("__pathExists", 1, prim_pathExists);
addPrimOp("baseNameOf", 1, prim_baseNameOf);
addPrimOp("dirOf", 1, prim_dirOf);
addPrimOp("__readFile", 1, prim_readFile);
addPrimOp("__findFile", 2, prim_findFile);
// Creating files
addPrimOp("__toXML", 1, prim_toXML);
addPrimOp("__toJSON", 1, prim_toJSON);
addPrimOp("__fromJSON", 1, prim_fromJSON);
addPrimOp("__toFile", 2, prim_toFile);
addPrimOp("__filterSource", 2, prim_filterSource);
// Sets
addPrimOp("__attrNames", 1, prim_attrNames);
addPrimOp("__getAttr", 2, prim_getAttr);
addPrimOp("__unsafeGetAttrPos", 2, prim_unsafeGetAttrPos);
addPrimOp("__hasAttr", 2, prim_hasAttr);
addPrimOp("__isAttrs", 1, prim_isAttrs);
addPrimOp("removeAttrs", 2, prim_removeAttrs);
addPrimOp("__listToAttrs", 1, prim_listToAttrs);
addPrimOp("__intersectAttrs", 2, prim_intersectAttrs);
addPrimOp("__functionArgs", 1, prim_functionArgs);
// Lists
addPrimOp("__isList", 1, prim_isList);
addPrimOp("__elemAt", 2, prim_elemAt);
addPrimOp("__head", 1, prim_head);
addPrimOp("__tail", 1, prim_tail);
addPrimOp("map", 2, prim_map);
addPrimOp("__filter", 2, prim_filter);
addPrimOp("__elem", 2, prim_elem);
addPrimOp("__concatLists", 1, prim_concatLists);
addPrimOp("__length", 1, prim_length);
// Integer arithmetic
addPrimOp("__add", 2, prim_add);
addPrimOp("__sub", 2, prim_sub);
addPrimOp("__mul", 2, prim_mul);
addPrimOp("__div", 2, prim_div);
addPrimOp("__lessThan", 2, prim_lessThan);
// String manipulation
addPrimOp("toString", 1, prim_toString);
addPrimOp("__substring", 3, prim_substring);
addPrimOp("__stringLength", 1, prim_stringLength);
addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
addPrimOp("__hashString", 2, prim_hashString);
// Versions
addPrimOp("__parseDrvName", 1, prim_parseDrvName);
addPrimOp("__compareVersions", 2, prim_compareVersions);
// Derivations
addPrimOp("derivationStrict", 1, prim_derivationStrict);
/* Add a wrapper around the derivation primop that computes the
`drvPath' and `outPath' attributes lazily. */
string path = findFile("nix/derivation.nix");
assert(!path.empty());
sDerivationNix = symbols.create(path);
evalFile(path, v);
addConstant("derivation", v);
/* Add a value containing the current Nix expression search path. */
mkList(v, searchPath.size());
int n = 0;
for (auto & i : searchPath) {
v2 = v.list.elems[n++] = allocValue();
mkAttrs(*v2, 2);
mkString(*allocAttr(*v2, symbols.create("path")), i.second);
mkString(*allocAttr(*v2, symbols.create("prefix")), i.first);
v2->attrs->sort();
}
addConstant("__nixPath", v);
/* Now that we've added all primops, sort the `builtins' set,
because attribute lookups expect it to be sorted. */
baseEnv.values[0]->attrs->sort();
}
}