lix/src/libexpr/eval.cc
Eelco Dolstra 816f9c0f6f * Use std::tr1::unordered_set instead of std::set for the symbol
table.  This gives a 10% speed increase on `nix-instantiate
  /etc/nixos/nixos -A system --readonly-mode'.
2010-04-13 14:34:11 +00:00

1066 lines
28 KiB
C++

#include "eval.hh"
#include "parser.hh"
#include "hash.hh"
#include "util.hh"
#include "store-api.hh"
#include "derivations.hh"
#include "globals.hh"
#include <cstring>
#define LocalNoInline(f) static f __attribute__((noinline)); f
#define LocalNoInlineNoReturn(f) static f __attribute__((noinline, noreturn)); f
namespace nix {
std::ostream & operator << (std::ostream & str, Value & v)
{
switch (v.type) {
case tInt:
str << v.integer;
break;
case tBool:
str << (v.boolean ? "true" : "false");
break;
case tString:
str << "\"";
for (const char * i = v.string.s; *i; i++)
if (*i == '\"' || *i == '\\') str << "\\" << *i;
else if (*i == '\n') str << "\\n";
else if (*i == '\r') str << "\\r";
else if (*i == '\t') str << "\\t";
else str << *i;
str << "\"";
break;
case tPath:
str << v.path; // !!! escaping?
break;
case tNull:
str << "true";
break;
case tAttrs:
str << "{ ";
foreach (Bindings::iterator, i, *v.attrs)
str << (string) i->first << " = " << i->second << "; ";
str << "}";
break;
case tList:
str << "[ ";
for (unsigned int n = 0; n < v.list.length; ++n)
str << v.list.elems[n] << " ";
str << "]";
break;
case tThunk:
case tCopy:
str << "<CODE>";
break;
case tLambda:
str << "<LAMBDA>";
break;
case tPrimOp:
str << "<PRIMOP>";
break;
case tPrimOpApp:
str << "<PRIMOP-APP>";
break;
default:
throw Error("invalid value");
}
return str;
}
string showType(Value & v)
{
switch (v.type) {
case tInt: return "an integer";
case tBool: return "a boolean";
case tString: return "a string";
case tPath: return "a path";
case tAttrs: return "an attribute set";
case tList: return "a list";
case tNull: return "null";
case tLambda: return "a function";
case tPrimOp: return "a built-in function";
case tPrimOpApp: return "a partially applied built-in function";
default: throw Error(format("unknown type: %1%") % v.type);
}
}
EvalState::EvalState()
: sWith(symbols.create("<with>"))
, sOutPath(symbols.create("outPath"))
, sDrvPath(symbols.create("drvPath"))
, sType(symbols.create("type"))
, sMeta(symbols.create("meta"))
, sName(symbols.create("name"))
, baseEnv(allocEnv())
{
nrValues = nrEnvs = nrEvaluated = recursionDepth = maxRecursionDepth = 0;
deepestStack = (char *) -1;
createBaseEnv();
allowUnsafeEquality = getEnv("NIX_NO_UNSAFE_EQ", "") == "";
}
EvalState::~EvalState()
{
assert(recursionDepth == 0);
}
void EvalState::addConstant(const string & name, Value & v)
{
baseEnv.bindings[symbols.create(name)] = v;
string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
(*baseEnv.bindings[symbols.create("builtins")].attrs)[symbols.create(name2)] = v;
nrValues += 2;
}
void EvalState::addPrimOp(const string & name,
unsigned int arity, PrimOp primOp)
{
Value v;
v.type = tPrimOp;
v.primOp.arity = arity;
v.primOp.fun = primOp;
baseEnv.bindings[symbols.create(name)] = v;
string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
(*baseEnv.bindings[symbols.create("builtins")].attrs)[symbols.create(name2)] = v;
nrValues += 2;
}
/* Every "format" object (even temporary) takes up a few hundred bytes
of stack space, which is a real killer in the recursive
evaluator. So here are some helper functions for throwing
exceptions. */
LocalNoInlineNoReturn(void throwEvalError(const char * s))
{
throw EvalError(s);
}
LocalNoInlineNoReturn(void throwEvalError(const char * s, const string & s2))
{
throw EvalError(format(s) % s2);
}
LocalNoInlineNoReturn(void throwEvalError(const char * s, const string & s2, const string & s3))
{
throw EvalError(format(s) % s2 % s3);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s))
{
throw TypeError(s);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const string & s2))
{
throw TypeError(format(s) % s2);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const Pos & pos, const string & s2))
{
throw TypeError(format(s) % pos % s2);
}
LocalNoInlineNoReturn(void throwTypeError(const char * s, const Pos & pos))
{
throw TypeError(format(s) % pos);
}
LocalNoInlineNoReturn(void throwAssertionError(const char * s, const Pos & pos))
{
throw AssertionError(format(s) % pos);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s))
{
e.addPrefix(s);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2))
{
e.addPrefix(format(s) % s2);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const Pos & pos))
{
e.addPrefix(format(s) % pos);
}
LocalNoInline(void addErrorPrefix(Error & e, const char * s, const string & s2, const string & s3))
{
e.addPrefix(format(s) % s2 % s3);
}
void mkString(Value & v, const char * s)
{
v.type = tString;
v.string.s = strdup(s);
v.string.context = 0;
}
void mkString(Value & v, const string & s, const PathSet & context)
{
mkString(v, s.c_str());
if (!context.empty()) {
unsigned int n = 0;
v.string.context = new const char *[context.size() + 1];
foreach (PathSet::const_iterator, i, context)
v.string.context[n++] = strdup(i->c_str());
v.string.context[n] = 0;
}
}
void mkPath(Value & v, const char * s)
{
v.type = tPath;
v.path = strdup(s);
}
Value * EvalState::lookupWith(Env * env, const Symbol & name)
{
if (!env) return 0;
Value * v = lookupWith(env->up, name);
if (v) return v;
Bindings::iterator i = env->bindings.find(sWith);
if (i == env->bindings.end()) return 0;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
return 0;
}
Value * EvalState::lookupVar(Env * env, const Symbol & name)
{
/* First look for a regular variable binding for `name'. */
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(name);
if (i != env2->bindings.end()) return &i->second;
}
/* Otherwise, look for a `with' attribute set containing `name'.
Outer `withs' take precedence (i.e. `with {x=1;}; with {x=2;};
x' evaluates to 1). */
Value * v = lookupWith(env, name);
if (v) return v;
/* Alternative implementation where the inner `withs' take
precedence (i.e. `with {x=1;}; with {x=2;}; x' evaluates to
2). */
#if 0
for (Env * env2 = env; env2; env2 = env2->up) {
Bindings::iterator i = env2->bindings.find(sWith);
if (i == env2->bindings.end()) continue;
Bindings::iterator j = i->second.attrs->find(name);
if (j != i->second.attrs->end()) return &j->second;
}
#endif
throwEvalError("undefined variable `%1%'", name);
}
Value * EvalState::allocValues(unsigned int count)
{
nrValues += count;
return new Value[count]; // !!! check destructor
}
Env & EvalState::allocEnv()
{
nrEnvs++;
return *(new Env);
}
void EvalState::mkList(Value & v, unsigned int length)
{
v.type = tList;
v.list.length = length;
v.list.elems = allocValues(length);
}
void EvalState::mkAttrs(Value & v)
{
v.type = tAttrs;
v.attrs = new Bindings;
}
void EvalState::mkThunk_(Value & v, Expr * expr)
{
mkThunk(v, baseEnv, expr);
}
void EvalState::cloneAttrs(Value & src, Value & dst)
{
mkAttrs(dst);
foreach (Bindings::iterator, i, *src.attrs)
mkCopy((*dst.attrs)[i->first], i->second);
}
void EvalState::evalFile(const Path & path, Value & v)
{
startNest(nest, lvlTalkative, format("evaluating file `%1%'") % path);
Expr * e = parseTrees[path];
if (!e) {
e = parseExprFromFile(*this, path);
parseTrees[path] = e;
}
try {
eval(e, v);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the file `%1%':\n", path);
throw;
}
}
struct RecursionCounter
{
EvalState & state;
RecursionCounter(EvalState & state) : state(state)
{
state.recursionDepth++;
if (state.recursionDepth > state.maxRecursionDepth)
state.maxRecursionDepth = state.recursionDepth;
}
~RecursionCounter()
{
state.recursionDepth--;
}
};
void EvalState::eval(Env & env, Expr * e, Value & v)
{
/* When changing this function, make sure that you don't cause a
(large) increase in stack consumption! */
/* !!! Disable this eventually. */
RecursionCounter r(*this);
char x;
if (&x < deepestStack) deepestStack = &x;
//debug(format("eval: %1%") % *e);
checkInterrupt();
nrEvaluated++;
e->eval(*this, env, v);
}
void EvalState::eval(Expr * e, Value & v)
{
eval(baseEnv, e, v);
}
bool EvalState::evalBool(Env & env, Expr * e)
{
Value v;
eval(env, e, v);
if (v.type != tBool)
throwTypeError("value is %1% while a Boolean was expected", showType(v));
return v.boolean;
}
void Expr::eval(EvalState & state, Env & env, Value & v)
{
abort();
}
void ExprInt::eval(EvalState & state, Env & env, Value & v)
{
mkInt(v, n);
}
void ExprString::eval(EvalState & state, Env & env, Value & v)
{
mkString(v, s.c_str());
}
void ExprPath::eval(EvalState & state, Env & env, Value & v)
{
mkPath(v, s.c_str());
}
void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
{
if (recursive) {
/* Create a new environment that contains the attributes in
this `rec'. */
Env & env2(state.allocEnv());
env2.up = &env;
v.type = tAttrs;
v.attrs = &env2.bindings;
/* The recursive attributes are evaluated in the new
environment. */
foreach (Attrs::iterator, i, attrs) {
Value & v2 = env2.bindings[i->first];
mkThunk(v2, env2, i->second);
}
/* The inherited attributes, on the other hand, are
evaluated in the original environment. */
foreach (list<Symbol>::iterator, i, inherited) {
Value & v2 = env2.bindings[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
}
else {
state.mkAttrs(v);
foreach (Attrs::iterator, i, attrs) {
Value & v2 = (*v.attrs)[i->first];
mkThunk(v2, env, i->second);
}
foreach (list<Symbol>::iterator, i, inherited) {
Value & v2 = (*v.attrs)[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
}
}
void ExprLet::eval(EvalState & state, Env & env, Value & v)
{
/* Create a new environment that contains the attributes in this
`let'. */
Env & env2(state.allocEnv());
env2.up = &env;
/* The recursive attributes are evaluated in the new
environment. */
foreach (ExprAttrs::Attrs::iterator, i, attrs->attrs) {
Value & v2 = env2.bindings[i->first];
mkThunk(v2, env2, i->second);
}
/* The inherited attributes, on the other hand, are evaluated in
the original environment. */
foreach (list<Symbol>::iterator, i, attrs->inherited) {
Value & v2 = env2.bindings[*i];
mkCopy(v2, *state.lookupVar(&env, *i));
}
state.eval(env2, body, v);
}
void ExprList::eval(EvalState & state, Env & env, Value & v)
{
state.mkList(v, elems.size());
for (unsigned int n = 0; n < v.list.length; ++n)
mkThunk(v.list.elems[n], env, elems[n]);
}
void ExprVar::eval(EvalState & state, Env & env, Value & v)
{
Value * v2 = state.lookupVar(&env, name);
state.forceValue(*v2);
v = *v2;
}
void ExprSelect::eval(EvalState & state, Env & env, Value & v)
{
Value v2;
state.eval(env, e, v2);
state.forceAttrs(v2); // !!! eval followed by force is slightly inefficient
Bindings::iterator i = v2.attrs->find(name);
if (i == v2.attrs->end())
throwEvalError("attribute `%1%' missing", name);
try {
state.forceValue(i->second);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the attribute `%1%':\n", name);
throw;
}
v = i->second;
}
void ExprOpHasAttr::eval(EvalState & state, Env & env, Value & v)
{
Value vAttrs;
state.eval(env, e, vAttrs);
state.forceAttrs(vAttrs);
mkBool(v, vAttrs.attrs->find(name) != vAttrs.attrs->end());
}
void ExprLambda::eval(EvalState & state, Env & env, Value & v)
{
v.type = tLambda;
v.lambda.env = &env;
v.lambda.fun = this;
}
void ExprApp::eval(EvalState & state, Env & env, Value & v)
{
Value vFun;
state.eval(env, e1, vFun);
Value vArg;
mkThunk(vArg, env, e2); // !!! should this be on the heap?
state.callFunction(vFun, vArg, v);
}
void EvalState::callFunction(Value & fun, Value & arg, Value & v)
{
if (fun.type == tPrimOp || fun.type == tPrimOpApp) {
unsigned int argsLeft =
fun.type == tPrimOp ? fun.primOp.arity : fun.primOpApp.argsLeft;
if (argsLeft == 1) {
/* We have all the arguments, so call the primop. First
find the primop. */
Value * primOp = &fun;
while (primOp->type == tPrimOpApp) primOp = primOp->primOpApp.left;
assert(primOp->type == tPrimOp);
unsigned int arity = primOp->primOp.arity;
/* Put all the arguments in an array. */
Value * vArgs[arity];
unsigned int n = arity - 1;
vArgs[n--] = &arg;
for (Value * arg = &fun; arg->type == tPrimOpApp; arg = arg->primOpApp.left)
vArgs[n--] = arg->primOpApp.right;
/* And call the primop. */
primOp->primOp.fun(*this, vArgs, v);
} else {
Value * v2 = allocValues(2);
v2[0] = fun;
v2[1] = arg;
v.type = tPrimOpApp;
v.primOpApp.left = &v2[0];
v.primOpApp.right = &v2[1];
v.primOpApp.argsLeft = argsLeft - 1;
}
return;
}
if (fun.type != tLambda)
throwTypeError("attempt to call something which is neither a function nor a primop (built-in operation) but %1%",
showType(fun));
Env & env2(allocEnv());
env2.up = fun.lambda.env;
if (!fun.lambda.fun->matchAttrs) {
Value & vArg = env2.bindings[fun.lambda.fun->arg];
nrValues++;
vArg = arg;
}
else {
forceAttrs(arg);
if (!fun.lambda.fun->arg.empty()) {
env2.bindings[fun.lambda.fun->arg] = arg;
nrValues++;
}
/* For each formal argument, get the actual argument. If
there is no matching actual argument but the formal
argument has a default, use the default. */
unsigned int attrsUsed = 0;
foreach (Formals::Formals_::iterator, i, fun.lambda.fun->formals->formals) {
Bindings::iterator j = arg.attrs->find(i->name);
Value & v = env2.bindings[i->name];
nrValues++;
if (j == arg.attrs->end()) {
if (!i->def) throwTypeError("function at %1% called without required argument `%2%'",
fun.lambda.fun->pos, i->name);
mkThunk(v, env2, i->def);
} else {
attrsUsed++;
mkCopy(v, j->second);
}
}
/* Check that each actual argument is listed as a formal
argument (unless the attribute match specifies a `...').
TODO: show the names of the expected/unexpected
arguments. */
if (!fun.lambda.fun->formals->ellipsis && attrsUsed != arg.attrs->size())
throwTypeError("function at %1% called with unexpected argument", fun.lambda.fun->pos);
}
try {
eval(env2, fun.lambda.fun->body, v);
} catch (Error & e) {
addErrorPrefix(e, "while evaluating the function at %1%:\n", fun.lambda.fun->pos);
throw;
}
}
void EvalState::autoCallFunction(const Bindings & args, Value & fun, Value & res)
{
forceValue(fun);
if (fun.type != tLambda || !fun.lambda.fun->matchAttrs) {
res = fun;
return;
}
Value actualArgs;
mkAttrs(actualArgs);
foreach (Formals::Formals_::iterator, i, fun.lambda.fun->formals->formals) {
Bindings::const_iterator j = args.find(i->name);
if (j != args.end())
(*actualArgs.attrs)[i->name] = j->second;
else if (!i->def)
throwTypeError("cannot auto-call a function that has an argument without a default value (`%1%')", i->name);
}
callFunction(fun, actualArgs, res);
}
void ExprWith::eval(EvalState & state, Env & env, Value & v)
{
Env & env2(state.allocEnv());
env2.up = &env;
Value & vAttrs = env2.bindings[state.sWith];
state.eval(env, attrs, vAttrs);
state.forceAttrs(vAttrs);
state.eval(env2, body, v);
}
void ExprIf::eval(EvalState & state, Env & env, Value & v)
{
state.eval(env, state.evalBool(env, cond) ? then : else_, v);
}
void ExprAssert::eval(EvalState & state, Env & env, Value & v)
{
if (!state.evalBool(env, cond))
throwAssertionError("assertion failed at %1%", pos);
state.eval(env, body, v);
}
void ExprOpNot::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, !state.evalBool(env, e));
}
void ExprOpEq::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
Value v2; state.eval(env, e2, v2);
mkBool(v, state.eqValues(v1, v2));
}
void ExprOpNEq::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
Value v2; state.eval(env, e2, v2);
mkBool(v, !state.eqValues(v1, v2));
}
void ExprOpAnd::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, state.evalBool(env, e1) && state.evalBool(env, e2));
}
void ExprOpOr::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, state.evalBool(env, e1) || state.evalBool(env, e2));
}
void ExprOpImpl::eval(EvalState & state, Env & env, Value & v)
{
mkBool(v, !state.evalBool(env, e1) || state.evalBool(env, e2));
}
void ExprOpUpdate::eval(EvalState & state, Env & env, Value & v)
{
Value v2;
state.eval(env, e1, v2);
state.forceAttrs(v2);
state.cloneAttrs(v2, v);
state.eval(env, e2, v2);
state.forceAttrs(v2);
foreach (Bindings::iterator, i, *v2.attrs)
(*v.attrs)[i->first] = i->second; // !!! sharing
}
void ExprOpConcatLists::eval(EvalState & state, Env & env, Value & v)
{
Value v1; state.eval(env, e1, v1);
state.forceList(v1);
Value v2; state.eval(env, e2, v2);
state.forceList(v2);
state.mkList(v, v1.list.length + v2.list.length);
/* !!! This loses sharing with the original lists. We could use a
tCopy node, but that would use more memory. */
for (unsigned int n = 0; n < v1.list.length; ++n)
v.list.elems[n] = v1.list.elems[n];
for (unsigned int n = 0; n < v2.list.length; ++n)
v.list.elems[n + v1.list.length] = v2.list.elems[n];
}
void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
{
PathSet context;
std::ostringstream s;
bool first = true, isPath = false;
Value vStr;
foreach (vector<Expr *>::iterator, i, *es) {
state.eval(env, *i, vStr);
/* If the first element is a path, then the result will also
be a path, we don't copy anything (yet - that's done later,
since paths are copied when they are used in a derivation),
and none of the strings are allowed to have contexts. */
if (first) {
isPath = vStr.type == tPath;
first = false;
}
s << state.coerceToString(vStr, context, false, !isPath);
}
if (isPath && !context.empty())
throwEvalError("a string that refers to a store path cannot be appended to a path, in `%1%'", s.str());
if (isPath)
mkPath(v, s.str().c_str());
else
mkString(v, s.str(), context);
}
void EvalState::forceValue(Value & v)
{
if (v.type == tThunk) {
ValueType saved = v.type;
try {
v.type = tBlackhole;
eval(*v.thunk.env, v.thunk.expr, v);
} catch (Error & e) {
v.type = saved;
throw;
}
}
else if (v.type == tCopy) {
forceValue(*v.val);
v = *v.val;
}
else if (v.type == tApp)
callFunction(*v.app.left, *v.app.right, v);
else if (v.type == tBlackhole)
throwEvalError("infinite recursion encountered");
}
void EvalState::strictForceValue(Value & v)
{
forceValue(v);
if (v.type == tAttrs) {
foreach (Bindings::iterator, i, *v.attrs)
strictForceValue(i->second);
}
else if (v.type == tList) {
for (unsigned int n = 0; n < v.list.length; ++n)
strictForceValue(v.list.elems[n]);
}
}
int EvalState::forceInt(Value & v)
{
forceValue(v);
if (v.type != tInt)
throwTypeError("value is %1% while an integer was expected", showType(v));
return v.integer;
}
bool EvalState::forceBool(Value & v)
{
forceValue(v);
if (v.type != tBool)
throwTypeError("value is %1% while a Boolean was expected", showType(v));
return v.boolean;
}
void EvalState::forceAttrs(Value & v)
{
forceValue(v);
if (v.type != tAttrs)
throwTypeError("value is %1% while an attribute set was expected", showType(v));
}
void EvalState::forceList(Value & v)
{
forceValue(v);
if (v.type != tList)
throwTypeError("value is %1% while a list was expected", showType(v));
}
void EvalState::forceFunction(Value & v)
{
forceValue(v);
if (v.type != tLambda && v.type != tPrimOp && v.type != tPrimOpApp)
throwTypeError("value is %1% while a function was expected", showType(v));
}
string EvalState::forceString(Value & v)
{
forceValue(v);
if (v.type != tString)
throwTypeError("value is %1% while a string was expected", showType(v));
return string(v.string.s);
}
string EvalState::forceString(Value & v, PathSet & context)
{
string s = forceString(v);
if (v.string.context)
for (const char * * p = v.string.context; *p; ++p)
context.insert(*p);
return s;
}
string EvalState::forceStringNoCtx(Value & v)
{
string s = forceString(v);
if (v.string.context)
throwEvalError("the string `%1%' is not allowed to refer to a store path (such as `%2%')",
v.string.s, v.string.context[0]);
return s;
}
bool EvalState::isDerivation(Value & v)
{
if (v.type != tAttrs) return false;
Bindings::iterator i = v.attrs->find(sType);
return i != v.attrs->end() && forceStringNoCtx(i->second) == "derivation";
}
string EvalState::coerceToString(Value & v, PathSet & context,
bool coerceMore, bool copyToStore)
{
forceValue(v);
string s;
if (v.type == tString) {
if (v.string.context)
for (const char * * p = v.string.context; *p; ++p)
context.insert(*p);
return v.string.s;
}
if (v.type == tPath) {
Path path(canonPath(v.path));
if (!copyToStore) return path;
if (nix::isDerivation(path))
throwEvalError("file names are not allowed to end in `%1%'", drvExtension);
Path dstPath;
if (srcToStore[path] != "")
dstPath = srcToStore[path];
else {
dstPath = readOnlyMode
? computeStorePathForPath(path).first
: store->addToStore(path);
srcToStore[path] = dstPath;
printMsg(lvlChatty, format("copied source `%1%' -> `%2%'")
% path % dstPath);
}
context.insert(dstPath);
return dstPath;
}
if (v.type == tAttrs) {
Bindings::iterator i = v.attrs->find(sOutPath);
if (i == v.attrs->end())
throwTypeError("cannot coerce an attribute set (except a derivation) to a string");
return coerceToString(i->second, context, coerceMore, copyToStore);
}
if (coerceMore) {
/* Note that `false' is represented as an empty string for
shell scripting convenience, just like `null'. */
if (v.type == tBool && v.boolean) return "1";
if (v.type == tBool && !v.boolean) return "";
if (v.type == tInt) return int2String(v.integer);
if (v.type == tNull) return "";
if (v.type == tList) {
string result;
for (unsigned int n = 0; n < v.list.length; ++n) {
result += coerceToString(v.list.elems[n],
context, coerceMore, copyToStore);
if (n < v.list.length - 1
/* !!! not quite correct */
&& (v.list.elems[n].type != tList || v.list.elems[n].list.length != 0))
result += " ";
}
return result;
}
}
throwTypeError("cannot coerce %1% to a string", showType(v));
}
Path EvalState::coerceToPath(Value & v, PathSet & context)
{
string path = coerceToString(v, context, false, false);
if (path == "" || path[0] != '/')
throwEvalError("string `%1%' doesn't represent an absolute path", path);
return path;
}
bool EvalState::eqValues(Value & v1, Value & v2)
{
forceValue(v1);
forceValue(v2);
/* !!! Hack to support some old broken code that relies on pointer
equality tests between attribute sets. (Specifically,
builderDefs calls uniqList on a list of attribute sets.) Will
remove this eventually. */
if (&v1 == &v2) return true;
if (v1.type != v2.type) return false;
switch (v1.type) {
case tInt:
return v1.integer == v2.integer;
case tBool:
return v1.boolean == v2.boolean;
case tString:
/* !!! contexts */
return strcmp(v1.string.s, v2.string.s) == 0;
case tPath:
return strcmp(v1.path, v2.path) == 0;
case tNull:
return true;
case tList:
if (v2.type != tList || v1.list.length != v2.list.length) return false;
for (unsigned int n = 0; n < v1.list.length; ++n)
if (!eqValues(v1.list.elems[n], v2.list.elems[n])) return false;
return true;
case tAttrs: {
if (v2.type != tAttrs || v1.attrs->size() != v2.attrs->size()) return false;
Bindings::iterator i, j;
for (i = v1.attrs->begin(), j = v2.attrs->begin(); i != v1.attrs->end(); ++i, ++j)
if (!eqValues(i->second, j->second)) return false;
return true;
}
/* Functions are incomparable. */
case tLambda:
case tPrimOp:
case tPrimOpApp:
return false;
default:
throwEvalError("cannot compare %1% with %2%", showType(v1), showType(v2));
}
}
void EvalState::printStats()
{
char x;
bool showStats = getEnv("NIX_SHOW_STATS", "0") != "0";
Verbosity v = showStats ? lvlInfo : lvlDebug;
printMsg(v, "evaluation statistics:");
printMsg(v, format(" expressions evaluated: %1%") % nrEvaluated);
printMsg(v, format(" stack space used: %1% bytes") % (&x - deepestStack));
printMsg(v, format(" max eval() nesting depth: %1%") % maxRecursionDepth);
printMsg(v, format(" stack space per eval() level: %1% bytes") % ((&x - deepestStack) / (float) maxRecursionDepth));
printMsg(v, format(" values allocated: %1%") % nrValues);
printMsg(v, format(" environments allocated: %1%") % nrEnvs);
printMsg(v, format(" symbols in symbol table: %1%") % symbols.size());
}
}