* Working evaluator.

* Mutually recursive attribute sets.
* Print evaluator efficiency statistics.
This commit is contained in:
Eelco Dolstra 2003-10-31 17:09:31 +00:00
parent f1c1a3c97f
commit 9210d4d530
10 changed files with 540 additions and 309 deletions

View file

@ -1,6 +1,6 @@
bin_PROGRAMS = fix-ng
fix_ng_SOURCES = fix-expr.cc parser.cc eval.cc fix.cc
fix_ng_SOURCES = fix-expr.cc parser.cc eval.cc primops.cc fix.cc
fix_ng_LDADD = ../libmain/libmain.a ../libnix/libnix.a ../boost/format/libformat.a \
-L../../externals/inst/lib -ldb_cxx -lsglr -lATB -lconversion -lasfix2 -lmept -lATerm

View file

@ -1,18 +1,167 @@
#include "eval.hh"
#include "expr.hh"
#include "parser.hh"
#include "primops.hh"
EvalState::EvalState()
{
blackHole = ATmake("BlackHole()");
if (!blackHole) throw Error("cannot build black hole");
nrEvaluated = nrCached = 0;
}
Expr getAttr(EvalState & state, Expr e, const string & name)
{
}
/* Substitute an argument set into the body of a function. */
static Expr substArgs(Expr body, ATermList formals, Expr arg)
{
Subs subs;
Expr undefined = ATmake("Undefined");
/* Get the formal arguments. */
while (!ATisEmpty(formals)) {
char * s;
if (!ATmatch(ATgetFirst(formals), "<str>", &s))
abort(); /* can't happen */
subs[s] = undefined;
formals = ATgetNext(formals);
}
/* Get the actual arguments, and check that they match with the
formals. */
Attrs args;
queryAllAttrs(arg, args);
for (Attrs::iterator i = args.begin(); i != args.end(); i++) {
if (subs.find(i->first) == subs.end())
throw badTerm(format("argument `%1%' not declared") % i->first, arg);
subs[i->first] = i->second;
}
/* Check that all arguments are defined. */
for (Subs::iterator i = subs.begin(); i != subs.end(); i++)
if (i->second == undefined)
throw badTerm(format("formal argument `%1%' missing") % i->first, arg);
return substitute(subs, body);
}
/* Transform a mutually recursive set into a non-recursive set. Each
attribute is transformed into an expression that has all references
to attributes substituted with selection expressions on the
original set. E.g., e = `rec {x = f x y, y = x}' becomes `{x = f
(e.x) (e.y), y = e.x}'. */
ATerm expandRec(ATerm e, ATermList bnds)
{
/* Create the substitution list. */
Subs subs;
ATermList bs = bnds;
while (!ATisEmpty(bs)) {
char * s;
Expr e2;
if (!ATmatch(ATgetFirst(bs), "Bind(<str>, <term>)", &s, &e2))
abort(); /* can't happen */
subs[s] = ATmake("Select(<term>, <str>)", e, s);
bs = ATgetNext(bs);
}
/* Create the non-recursive set. */
Attrs as;
bs = bnds;
while (!ATisEmpty(bs)) {
char * s;
Expr e2;
if (!ATmatch(ATgetFirst(bs), "Bind(<str>, <term>)", &s, &e2))
abort(); /* can't happen */
as[s] = substitute(subs, e2);
bs = ATgetNext(bs);
}
return makeAttrs(as);
}
string evalString(EvalState & state, Expr e)
{
e = evalExpr(state, e);
char * s;
if (!ATmatch(e, "Str(<str>)", &s))
throw badTerm("string expected", e);
return s;
}
Path evalPath(EvalState & state, Expr e)
{
e = evalExpr(state, e);
char * s;
if (!ATmatch(e, "Path(<str>)", &s))
throw badTerm("path expected", e);
return s;
}
Expr evalExpr2(EvalState & state, Expr e)
{
return e;
Expr e1, e2, e3, e4;
char * s1;
/* Normal forms. */
if (ATmatch(e, "Str(<str>)", &s1) ||
ATmatch(e, "Path(<str>)", &s1) ||
ATmatch(e, "Uri(<str>)", &s1) ||
ATmatch(e, "Function([<list>], <term>)", &e1, &e2) ||
ATmatch(e, "Attrs([<list>])", &e1) ||
ATmatch(e, "List([<list>])", &e1))
return e;
/* Any encountered variables must be undeclared or primops. */
if (ATmatch(e, "Var(<str>)", &s1)) {
return e;
}
/* Function application. */
if (ATmatch(e, "Call(<term>, <term>)", &e1, &e2)) {
/* Evaluate the left-hand side. */
e1 = evalExpr(state, e1);
/* Is it a primop or a function? */
if (ATmatch(e1, "Var(<str>)", &s1)) {
string primop(s1);
if (primop == "import") return primImport(state, e2);
if (primop == "derivation") return primDerivation(state, e2);
else throw badTerm("undefined variable/primop", e1);
}
else if (ATmatch(e1, "Function([<list>], <term>)", &e3, &e4)) {
return evalExpr(state,
substArgs(e4, (ATermList) e3, evalExpr(state, e2)));
}
else throw badTerm("expecting a function or primop", e1);
}
/* Attribute selection. */
if (ATmatch(e, "Select(<term>, <str>)", &e1, &s1)) {
string name(s1);
Expr a = queryAttr(evalExpr(state, e1), name);
if (!a) throw badTerm(format("missing attribute `%1%'") % name, e);
return evalExpr(state, a);
}
/* Mutually recursive sets. */
ATermList bnds;
if (ATmatch(e, "Rec([<list>])", &bnds))
return expandRec(e, (ATermList) bnds);
/* Barf. */
throw badTerm("invalid expression", e);
}
@ -20,12 +169,15 @@ Expr evalExpr(EvalState & state, Expr e)
{
Nest nest(lvlVomit, format("evaluating expression: %1%") % printTerm(e));
state.nrEvaluated++;
/* Consult the memo table to quickly get the normal form of
previously evaluated expressions. */
NormalForms::iterator i = state.normalForms.find(e);
if (i != state.normalForms.end()) {
if (i->second == state.blackHole)
throw badTerm("infinite recursion", e);
state.nrCached++;
return i->second;
}
@ -43,3 +195,11 @@ Expr evalFile(EvalState & state, const Path & path)
Expr e = parseExprFromFile(path);
return evalExpr(state, e);
}
void printEvalStats(EvalState & state)
{
debug(format("evaluated %1% expressions, %2% cache hits, %3%%% efficiency")
% state.nrEvaluated % state.nrCached
% ((float) state.nrCached / (float) state.nrEvaluated * 100));
}

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@ -4,19 +4,23 @@
#include <map>
#include "fix-expr.hh"
#include "expr.hh"
typedef map<Expr, Expr> NormalForms;
//typedef map<Path, PathSet> PkgPaths;
//typedef map<Path, Hash> PkgHashes;
typedef map<Path, PathSet> DrvPaths;
typedef map<Path, Hash> DrvHashes;
struct EvalState
{
NormalForms normalForms;
// PkgPaths pkgPaths;
// PkgHashes pkgHashes; /* normalised package hashes */
DrvPaths drvPaths;
DrvHashes drvHashes; /* normalised derivation hashes */
Expr blackHole;
unsigned int nrEvaluated;
unsigned int nrCached;
EvalState();
};
@ -27,5 +31,12 @@ Expr evalExpr(EvalState & state, Expr e);
/* Evaluate an expression read from the given file to normal form. */
Expr evalFile(EvalState & state, const Path & path);
/* Specific results. */
string evalString(EvalState & state, Expr e);
Path evalPath(EvalState & state, Expr e);
/* Print statistics. */
void printEvalStats(EvalState & state);
#endif /* !__EVAL_H */

View file

@ -31,3 +31,96 @@ ATerm bottomupRewrite(TermFun & f, ATerm e)
return e;
}
void queryAllAttrs(Expr e, Attrs & attrs)
{
ATermList bnds;
if (!ATmatch(e, "Attrs([<list>])", &bnds))
throw badTerm("expected attribute set", e);
while (!ATisEmpty(bnds)) {
char * s;
Expr e;
if (!ATmatch(ATgetFirst(bnds), "Bind(<str>, <term>)", &s, &e))
abort(); /* can't happen */
attrs[s] = e;
bnds = ATgetNext(bnds);
}
}
Expr queryAttr(Expr e, const string & name)
{
Attrs attrs;
queryAllAttrs(e, attrs);
Attrs::iterator i = attrs.find(name);
return i == attrs.end() ? 0 : i->second;
}
Expr makeAttrs(const Attrs & attrs)
{
ATermList bnds = ATempty;
for (Attrs::const_iterator i = attrs.begin(); i != attrs.end(); i++)
bnds = ATinsert(bnds,
ATmake("Bind(<str>, <term>)", i->first.c_str(), i->second));
return ATmake("Attrs(<term>)", ATreverse(bnds));
}
ATerm substitute(Subs & subs, ATerm e)
{
char * s;
if (ATmatch(e, "Var(<str>)", &s)) {
Subs::iterator i = subs.find(s);
if (i == subs.end())
return e;
else
return i->second;
}
/* In case of a function, filter out all variables bound by this
function. */
ATermList formals;
ATerm body;
if (ATmatch(e, "Function([<list>], <term>)", &formals, &body)) {
Subs subs2(subs);
ATermList fs = formals;
while (!ATisEmpty(fs)) {
if (!ATmatch(ATgetFirst(fs), "<str>", &s)) abort();
subs2.erase(s);
fs = ATgetNext(fs);
}
return ATmake("Function(<term>, <term>)", formals,
substitute(subs2, body));
}
/* !!! Rec(...) */
if (ATgetType(e) == AT_APPL) {
AFun fun = ATgetAFun(e);
int arity = ATgetArity(fun);
ATermList args = ATempty;
for (int i = arity - 1; i >= 0; i--)
args = ATinsert(args, substitute(subs, ATgetArgument(e, i)));
return (ATerm) ATmakeApplList(fun, args);
}
if (ATgetType(e) == AT_LIST) {
ATermList in = (ATermList) e;
ATermList out = ATempty;
while (!ATisEmpty(in)) {
out = ATinsert(out, substitute(subs, ATgetFirst(in)));
in = ATgetNext(in);
}
return (ATerm) ATreverse(out);
}
return e;
}

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@ -1,6 +1,8 @@
#ifndef __FIXEXPR_H
#define __FIXEXPR_H
#include <map>
#include <aterm2.h>
#include "util.hh"
@ -15,13 +17,27 @@ typedef ATerm Expr;
/* Generic bottomup traversal over ATerms. The traversal first
recursively descends into subterms, and then applies the given term
function to the resulting term. */
struct TermFun
{
virtual ATerm operator () (ATerm e) = 0;
};
ATerm bottomupRewrite(TermFun & f, ATerm e);
/* Query all attributes in an attribute set expression. The
expression must be in normal form. */
typedef map<string, Expr> Attrs;
void queryAllAttrs(Expr e, Attrs & attrs);
/* Query a specific attribute from an attribute set expression. The
expression must be in normal form. */
Expr queryAttr(Expr e, const string & name);
/* Create an attribute set expression from an Attrs value. */
Expr makeAttrs(const Attrs & attrs);
/* Perform a set of substitutions on an expression. */
typedef map<string, Expr> Subs;
ATerm substitute(Subs & subs, ATerm e);
#endif /* !__FIXEXPR_H */

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@ -8,7 +8,6 @@
#include "eval.hh"
#if 0
#if 0
static Path searchPath(const Paths & searchDirs, const Path & relPath)
{
@ -28,178 +27,9 @@ static Path searchPath(const Paths & searchDirs, const Path & relPath)
#endif
static Expr substExpr(string x, Expr rep, Expr e)
{
char * s;
Expr e2;
if (ATmatch(e, "Var(<str>)", &s))
if (x == s)
return rep;
else
return e;
ATermList formals;
if (ATmatch(e, "Function([<list>], <term>)", &formals, &e2)) {
while (!ATisEmpty(formals)) {
if (!ATmatch(ATgetFirst(formals), "<str>", &s))
throw badTerm("not a list of formals", (ATerm) formals);
if (x == (string) s)
return e;
formals = ATgetNext(formals);
}
}
/* Generically substitute in subterms. */
if (ATgetType(e) == AT_APPL) {
AFun fun = ATgetAFun(e);
int arity = ATgetArity(fun);
ATermList args = ATempty;
for (int i = arity - 1; i >= 0; i--)
args = ATinsert(args, substExpr(x, rep, ATgetArgument(e, i)));
return (ATerm) ATmakeApplList(fun, args);
}
if (ATgetType(e) == AT_LIST) {
ATermList in = (ATermList) e;
ATermList out = ATempty;
while (!ATisEmpty(in)) {
out = ATinsert(out, substExpr(x, rep, ATgetFirst(in)));
in = ATgetNext(in);
}
return (ATerm) ATreverse(out);
}
throw badTerm("do not know how to substitute", e);
}
static Expr substExprMany(ATermList formals, ATermList args, Expr body)
{
char * s;
Expr e;
/* !!! check args against formals */
while (!ATisEmpty(args)) {
ATerm tup = ATgetFirst(args);
if (!ATmatch(tup, "(<str>, <term>)", &s, &e))
throw badTerm("expected an argument tuple", tup);
body = substExpr(s, e, body);
args = ATgetNext(args);
}
return body;
}
static PathSet nixExprRootsCached(EvalState & state, const Path & nePath)
{
PkgPaths::iterator i = state.pkgPaths.find(nePath);
if (i != state.pkgPaths.end())
return i->second;
else {
PathSet paths = nixExprRoots(nePath);
state.pkgPaths[nePath] = paths;
return paths;
}
}
static Hash hashPackage(EvalState & state, NixExpr ne)
{
if (ne.type == NixExpr::neDerivation) {
PathSet inputs2;
for (PathSet::iterator i = ne.derivation.inputs.begin();
i != ne.derivation.inputs.end(); i++)
{
PkgHashes::iterator j = state.pkgHashes.find(*i);
if (j == state.pkgHashes.end())
throw Error(format("don't know expression `%1%'") % (string) *i);
inputs2.insert(j->second);
}
ne.derivation.inputs = inputs2;
}
return hashTerm(unparseNixExpr(ne));
}
static string processBinding(EvalState & state, Expr e, NixExpr & ne)
{
char * s1;
if (ATmatch(e, "NixExpr(<str>)", &s1)) {
Path nePath(s1);
PathSet paths = nixExprRootsCached(state, nePath);
if (paths.size() != 1) abort();
Path path = *(paths.begin());
ne.derivation.inputs.insert(nePath);
return path;
}
if (ATmatch(e, "<str>", &s1))
return s1;
if (ATmatch(e, "True")) return "1";
if (ATmatch(e, "False")) return "";
ATermList l;
if (ATmatch(e, "[<list>]", &l)) {
string s;
bool first = true;
while (!ATisEmpty(l)) {
if (!first) s = s + " "; else first = false;
s += processBinding(state, evalExpr(state, ATgetFirst(l)), ne);
l = ATgetNext(l);
}
return s;
}
throw badTerm("invalid package binding", e);
}
#if 0
static Expr evalExpr2(EvalState & state, Expr e)
{
char * s1;
Expr e1, e2, e3, e4;
ATermList bnds;
/* Normal forms. */
if (ATmatch(e, "<str>", &s1) ||
ATmatch(e, "[<list>]", &e1) ||
ATmatch(e, "True") ||
ATmatch(e, "False") ||
ATmatch(e, "Function([<list>], <term>)", &e1, &e2) ||
ATmatch(e, "NixExpr(<str>)", &s1))
return e;
try {
Hash pkgHash = hashPackage(state, parseNixExpr(e));
Path pkgPath = writeTerm(e, "");
state.pkgHashes[pkgPath] = pkgHash;
return ATmake("NixExpr(<str>)", pkgPath.c_str());
} catch (...) { /* !!! catch parse errors only */
}
/* Application. */
if (ATmatch(e, "Call(<term>, [<list>])", &e1, &e2) ||
ATmatch(e, "App(<term>, [<list>])", &e1, &e2)) {
e1 = evalExpr(state, e1);
if (!ATmatch(e1, "Function([<list>], <term>)", &e3, &e4))
throw badTerm("expecting a function", e1);
return evalExpr(state,
substExprMany((ATermList) e3, (ATermList) e2, e4));
}
/* Conditional. */
if (ATmatch(e, "If(<term>, <term>, <term>)", &e1, &e2, &e3)) {
e1 = evalExpr(state, e1);
@ -226,127 +56,6 @@ static Expr evalExpr2(EvalState & state, Expr e)
ATmake("True") : ATmake("False");
}
/* Platform constant. */
if (ATmatch(e, "Platform")) {
return ATmake("<str>", thisSystem.c_str());
}
/* Fix inclusion. */
if (ATmatch(e, "IncludeFix(<str>)", &s1)) {
Path fileName(s1);
return evalFile(state, s1);
}
/* Relative files. */
if (ATmatch(e, "Relative(<str>)", &s1)) {
Path srcPath = s1;
Path dstPath = addToStore(srcPath);
ClosureElem elem;
NixExpr ne;
ne.type = NixExpr::neClosure;
ne.closure.roots.insert(dstPath);
ne.closure.elems[dstPath] = elem;
Hash pkgHash = hashPackage(state, ne);
Path pkgPath = writeTerm(unparseNixExpr(ne), "");
state.pkgHashes[pkgPath] = pkgHash;
msg(lvlChatty, format("copied `%1%' -> closure `%2%'")
% srcPath % pkgPath);
return ATmake("NixExpr(<str>)", pkgPath.c_str());
}
/* Packages are transformed into Nix derivation expressions. */
if (ATmatch(e, "Package([<list>])", &bnds)) {
/* Evaluate the bindings and put them in a map. */
map<string, ATerm> bndMap;
bndMap["platform"] = ATmake("<str>", thisSystem.c_str());
while (!ATisEmpty(bnds)) {
ATerm bnd = ATgetFirst(bnds);
if (!ATmatch(bnd, "(<str>, <term>)", &s1, &e1))
throw badTerm("binding expected", bnd);
bndMap[s1] = evalExpr(state, e1);
bnds = ATgetNext(bnds);
}
/* Gather information for building the derivation
expression. */
NixExpr ne;
ne.type = NixExpr::neDerivation;
ne.derivation.platform = thisSystem;
string name;
Path outPath;
Hash outHash;
bool outHashGiven = false;
bnds = ATempty;
for (map<string, ATerm>::iterator it = bndMap.begin();
it != bndMap.end(); it++)
{
string key = it->first;
ATerm value = it->second;
if (key == "args") {
ATermList args;
if (!ATmatch(value, "[<list>]", &args))
throw badTerm("list expected", value);
while (!ATisEmpty(args)) {
Expr arg = evalExpr(state, ATgetFirst(args));
ne.derivation.args.push_back(processBinding(state, arg, ne));
args = ATgetNext(args);
}
}
else {
string s = processBinding(state, value, ne);
ne.derivation.env[key] = s;
if (key == "build") ne.derivation.builder = s;
if (key == "name") name = s;
if (key == "outPath") outPath = s;
if (key == "id") {
outHash = parseHash(s);
outHashGiven = true;
}
}
bnds = ATinsert(bnds,
ATmake("(<str>, <term>)", key.c_str(), value));
}
if (ne.derivation.builder == "")
throw badTerm("no builder specified", e);
if (name == "")
throw badTerm("no package name specified", e);
/* Determine the output path. */
if (!outHashGiven) outHash = hashPackage(state, ne);
if (outPath == "")
/* Hash the Nix expression with no outputs to produce a
unique but deterministic path name for this package. */
outPath =
canonPath(nixStore + "/" + ((string) outHash).c_str() + "-" + name);
ne.derivation.env["out"] = outPath;
ne.derivation.outputs.insert(outPath);
/* Write the resulting term into the Nix store directory. */
Hash pkgHash = outHashGiven
? hashString((string) outHash + outPath)
: hashPackage(state, ne);
Path pkgPath = writeTerm(unparseNixExpr(ne), "-d-" + name);
state.pkgHashes[pkgPath] = pkgHash;
msg(lvlChatty, format("instantiated `%1%' -> `%2%'")
% name % pkgPath);
return ATmake("NixExpr(<str>)", pkgPath.c_str());
}
/* BaseName primitive function. */
if (ATmatch(e, "BaseName(<term>)", &e1)) {
e1 = evalExpr(state, e1);
@ -355,8 +64,6 @@ static Expr evalExpr2(EvalState & state, Expr e)
return ATmake("<str>", baseNameOf(s1).c_str());
}
/* Barf. */
throw badTerm("invalid expression", e);
}
#endif
@ -374,17 +81,27 @@ static Expr evalStdin(EvalState & state)
static void printNixExpr(EvalState & state, Expr e)
{
ATermList es;
char * s;
if (ATmatch(e, "NixExpr(<str>)", &s)) {
cout << format("%1%\n") % s;
}
else if (ATmatch(e, "[<list>]", &es)) {
if (ATmatch(e, "Attrs([<list>])", &es)) {
Expr a = queryAttr(e, "type");
if (a && evalString(state, a) == "derivation") {
a = queryAttr(e, "drvPath");
if (a) {
cout << format("%1%\n") % evalPath(state, a);
return;
}
}
}
if (ATmatch(e, "[<list>]", &es)) {
while (!ATisEmpty(es)) {
printNixExpr(state, evalExpr(state, ATgetFirst(es)));
es = ATgetNext(es);
}
return;
}
else throw badTerm("top level does not evaluate to a (list of) Nix expression(s)", e);
throw badTerm("top level does not evaluate to one or more Nix expressions", e);
}
@ -435,6 +152,8 @@ void run(Strings args)
Expr e = evalFile(state, absPath(*it));
printNixExpr(state, e);
}
printEvalStats(state);
}

View file

@ -44,6 +44,9 @@ exports
"{" {Id ","}* "}" ":" Expr
-> Expr {cons("Function"), right}
"rec" "{" {Bind ","}* "}"
-> Expr {cons("Rec")}
"{" {Bind ","}* "}"
-> Expr {cons("Attrs")}
@ -71,6 +74,7 @@ exports
sorts Id Path
lexical syntax
[a-zA-Z\_][a-zA-Z0-9\_\']* -> Id
"rec" -> Id {reject}
[0-9]+ -> Int
"\"" ~[\n\"]* "\"" -> Str
PathComp ("/" PathComp)+ -> Path

View file

@ -40,7 +40,7 @@ struct Cleanup : TermFun
string path(s);
if (path[0] != '/')
path = basePath + "/" + path;
return ATmake("Str(<str>)", canonPath(path).c_str());
return ATmake("Path(<str>)", canonPath(path).c_str());
}
if (ATmatch(e, "Int(<str>)", &s)) {

206
src/fix-ng/primops.cc Normal file
View file

@ -0,0 +1,206 @@
#include "primops.hh"
#include "normalise.hh"
#include "globals.hh"
Expr primImport(EvalState & state, Expr arg)
{
char * path;
if (!ATmatch(arg, "Path(<str>)", &path))
throw badTerm("path expected", arg);
return evalFile(state, path);
}
static PathSet nixExprRootsCached(EvalState & state, const Path & nePath)
{
DrvPaths::iterator i = state.drvPaths.find(nePath);
if (i != state.drvPaths.end())
return i->second;
else {
PathSet paths = nixExprRoots(nePath);
state.drvPaths[nePath] = paths;
return paths;
}
}
static Hash hashDerivation(EvalState & state, NixExpr ne)
{
if (ne.type == NixExpr::neDerivation) {
PathSet inputs2;
for (PathSet::iterator i = ne.derivation.inputs.begin();
i != ne.derivation.inputs.end(); i++)
{
DrvHashes::iterator j = state.drvHashes.find(*i);
if (j == state.drvHashes.end())
throw Error(format("don't know expression `%1%'") % (string) *i);
inputs2.insert(j->second);
}
ne.derivation.inputs = inputs2;
}
return hashTerm(unparseNixExpr(ne));
}
static Path copyAtom(EvalState & state, const Path & srcPath)
{
/* !!! should be cached */
Path dstPath(addToStore(srcPath));
ClosureElem elem;
NixExpr ne;
ne.type = NixExpr::neClosure;
ne.closure.roots.insert(dstPath);
ne.closure.elems[dstPath] = elem;
Hash drvHash = hashDerivation(state, ne);
Path drvPath = writeTerm(unparseNixExpr(ne), "");
state.drvHashes[drvPath] = drvHash;
msg(lvlChatty, format("copied `%1%' -> closure `%2%'")
% srcPath % drvPath);
return drvPath;
}
static string addInput(EvalState & state,
Path & nePath, NixExpr & ne)
{
PathSet paths = nixExprRootsCached(state, nePath);
if (paths.size() != 1) abort();
Path path = *(paths.begin());
ne.derivation.inputs.insert(nePath);
return path;
}
static string processBinding(EvalState & state, Expr e, NixExpr & ne)
{
e = evalExpr(state, e);
char * s;
ATermList es;
if (ATmatch(e, "Str(<str>)", &s)) return s;
if (ATmatch(e, "Uri(<str>)", &s)) return s;
if (ATmatch(e, "True")) return "1";
if (ATmatch(e, "False")) return "";
if (ATmatch(e, "Attrs([<list>])", &es)) {
Expr a = queryAttr(e, "type");
if (a && evalString(state, a) == "derivation") {
a = queryAttr(e, "drvPath");
if (a) {
Path drvPath = evalPath(state, a);
return addInput(state, drvPath, ne);
}
}
}
if (ATmatch(e, "Path(<str>)", &s)) {
Path drvPath = copyAtom(state, s);
return addInput(state, drvPath, ne);
}
if (ATmatch(e, "List([<list>])", &es)) {
string s;
bool first = true;
while (!ATisEmpty(es)) {
Nest nest(lvlVomit, format("processing list element"));
if (!first) s = s + " "; else first = false;
s += processBinding(state, evalExpr(state, ATgetFirst(es)), ne);
es = ATgetNext(es);
}
return s;
}
throw badTerm("invalid derivation binding", e);
}
Expr primDerivation(EvalState & state, Expr args)
{
Nest nest(lvlVomit, "evaluating derivation");
Attrs attrs;
args = evalExpr(state, args);
queryAllAttrs(args, attrs);
/* Build the derivation expression by processing the attributes. */
NixExpr ne;
ne.type = NixExpr::neDerivation;
string drvName;
Path outPath;
Hash outHash;
bool outHashGiven = false;
for (Attrs::iterator i = attrs.begin(); i != attrs.end(); i++) {
string key = i->first;
Expr value = i->second;
Nest nest(lvlVomit, format("processing attribute `%1%'") % key);
/* The `args' attribute is special: it supplies the
command-line arguments to the builder. */
if (key == "args") {
ATermList args;
if (!ATmatch(value, "[<list>]", &args))
throw badTerm("list expected", value);
while (!ATisEmpty(args)) {
Expr arg = evalExpr(state, ATgetFirst(args));
ne.derivation.args.push_back(processBinding(state, arg, ne));
args = ATgetNext(args);
}
}
/* All other attributes are passed to the builder through the
environment. */
else {
string s = processBinding(state, value, ne);
ne.derivation.env[key] = s;
if (key == "builder") ne.derivation.builder = s;
else if (key == "system") ne.derivation.platform = s;
else if (key == "name") drvName = s;
else if (key == "outPath") outPath = s;
else if (key == "id") {
outHash = parseHash(s);
outHashGiven = true;
}
}
}
/* Do we have all required attributes? */
if (ne.derivation.builder == "")
throw badTerm("required attribute `builder' missing", args);
if (ne.derivation.platform == "")
throw badTerm("required attribute `system' missing", args);
if (drvName == "")
throw badTerm("required attribute `name' missing", args);
/* Determine the output path. */
if (!outHashGiven) outHash = hashDerivation(state, ne);
if (outPath == "")
/* Hash the Nix expression with no outputs to produce a
unique but deterministic path name for this derivation. */
outPath = canonPath(nixStore + "/" +
((string) outHash).c_str() + "-" + drvName);
ne.derivation.env["out"] = outPath;
ne.derivation.outputs.insert(outPath);
/* Write the resulting term into the Nix store directory. */
Hash drvHash = outHashGiven
? hashString((string) outHash + outPath)
: hashDerivation(state, ne);
Path drvPath = writeTerm(unparseNixExpr(ne), "-d-" + drvName);
state.drvHashes[drvPath] = drvHash;
msg(lvlChatty, format("instantiated `%1%' -> `%2%'")
% drvName % drvPath);
attrs["outPath"] = ATmake("Path(<str>)", outPath.c_str());
attrs["drvPath"] = ATmake("Path(<str>)", drvPath.c_str());
attrs["type"] = ATmake("Str(\"derivation\")");
return makeAttrs(attrs);
}

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src/fix-ng/primops.hh Normal file
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#ifndef __PRIMOPS_H
#define __PRIMOPS_H
#include "eval.hh"
/* Load and evaluate an expression from path specified by the
argument. */
Expr primImport(EvalState & state, Expr arg);
/* 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. */
Expr primDerivation(EvalState & state, Expr args);
#endif /* !__PRIMOPS_H */