lix/src/fix.cc

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#include <map>
#include <iostream>
#include "globals.hh"
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#include "fstate.hh"
#include "store.hh"
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#include "shared.hh"
typedef ATerm Expr;
static Expr evalFile(string fileName);
static bool isFState(Expr e, string & path)
{
char * s1, * s2, * s3;
Expr e1, e2;
if (ATmatch(e, "Path(<str>, <term>, [<list>])", &s1, &e1, &e2)) {
path = s1;
return true;
}
else if (ATmatch(e, "Derive(<str>, <str>, [<list>], <str>, [<list>])",
&s1, &s2, &e1, &s3, &e2))
{
path = s3;
return true;
}
else if (ATmatch(e, "Include(<str>)", &s1))
{
string fn = queryPathByHash(parseHash(s1));
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return isFState(evalFile(fn), path);
}
else return false;
}
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;
if (ATmatch(e, "Lam(<str>, <term>)", &s, &e2))
if (x == s)
return e;
/* !!! unfair substitutions */
/* 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 Expr evalExpr(Expr e)
{
char * s1;
Expr e1, e2, e3, e4;
ATermList bnds;
/* Normal forms. */
if (ATmatch(e, "<str>", &s1) ||
ATmatch(e, "Function([<list>], <term>)", &e1, &e2))
return e;
string dummy;
if (isFState(e, dummy)) return e;
/* Application. */
if (ATmatch(e, "App(<term>, [<list>])", &e1, &e2)) {
e1 = evalExpr(e1);
if (!ATmatch(e1, "Function([<list>], <term>)", &e3, &e4))
throw badTerm("expecting a function", e1);
return evalExpr(substExprMany((ATermList) e3, (ATermList) e2, e4));
}
/* Fix inclusion. */
if (ATmatch(e, "IncludeFix(<str>)", &s1)) {
string fileName(s1);
return evalFile(s1);
}
/* Relative files. */
if (ATmatch(e, "Relative(<str>)", &s1)) {
string srcPath = s1;
string dstPath;
Hash hash;
addToStore(srcPath, dstPath, hash);
return ATmake("Path(<str>, Hash(<str>), [])",
dstPath.c_str(), ((string) hash).c_str());
}
/* Packages are transformed into Derive fstate expressions. */
if (ATmatch(e, "Package([<list>])", &bnds)) {
/* Evaluate the bindings and put them in a map. */
map<string, ATerm> bndMap;
bndMap["platform"] = ATmake("<str>", SYSTEM);
while (!ATisEmpty(bnds)) {
ATerm bnd = ATgetFirst(bnds);
if (!ATmatch(bnd, "(<str>, <term>)", &s1, &e1))
throw badTerm("binding expected", bnd);
bndMap[s1] = evalExpr(e1);
bnds = ATgetNext(bnds);
}
/* Gather information for building the Derive expression. */
ATermList ins = ATempty, env = ATempty;
string builder, name;
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bnds = ATempty;
for (map<string, ATerm>::iterator it = bndMap.begin();
it != bndMap.end(); it++)
{
string key = it->first;
ATerm value = it->second;
string path;
if (isFState(value, path)) {
ins = ATinsert(ins, value);
env = ATinsert(env, ATmake("(<str>, <str>)",
key.c_str(), path.c_str()));
if (key == "build") builder = path;
}
else if (ATmatch(value, "<str>", &s1)) {
if (key == "name") name = s1;
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env = ATinsert(env,
ATmake("(<str>, <str>)", key.c_str(), s1));
}
else throw badTerm("invalid package argument", value);
bnds = ATinsert(bnds,
ATmake("(<str>, <term>)", key.c_str(), value));
}
/* Hash the normal form to produce a unique but deterministic
path name for this package. */
ATerm nf = ATmake("Package(<term>)", ATreverse(bnds));
Hash hash = hashTerm(nf);
if (builder == "")
throw badTerm("no builder specified", nf);
if (name == "")
throw badTerm("no package name specified", nf);
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string out = nixStore + "/" + ((string) hash).c_str() + "-" + name;
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env = ATinsert(env, ATmake("(<str>, <str>)", "out", out.c_str()));
/* Construct the result. */
e = ATmake("Derive(<str>, <str>, <term>, <str>, <term>)",
SYSTEM, builder.c_str(), ins, out.c_str(), env);
/* Write the resulting term into the Nix store directory. */
Hash eHash = writeTerm(e);
return ATmake("Include(<str>)", ((string) eHash).c_str());
}
/* BaseName primitive function. */
if (ATmatch(e, "BaseName(<term>)", &e1)) {
e1 = evalExpr(e1);
if (!ATmatch(e1, "<str>", &s1))
throw badTerm("string expected", e1);
return ATmake("<str>", baseNameOf(s1).c_str());
}
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/* Barf. */
throw badTerm("invalid expression", e);
}
static Strings searchPath;
static Expr evalFile(string fileName)
{
Expr e = ATreadFromNamedFile(fileName.c_str());
if (!e) throw Error(format("cannot read aterm `%1%'") % fileName);
return evalExpr(e);
}
void run(Strings args)
{
Strings files;
searchPath.push_back(".");
for (Strings::iterator it = args.begin();
it != args.end(); )
{
string arg = *it++;
if (arg == "--includedir" || arg == "-I") {
if (it == args.end())
throw UsageError(format("argument required in `%1%'") % arg);
searchPath.push_back(*it++);
}
else if (arg[0] == '-')
throw UsageError(format("unknown flag `%1%`") % arg);
else
files.push_back(arg);
}
if (files.empty()) throw UsageError("no files specified");
for (Strings::iterator it = files.begin();
it != files.end(); it++)
{
Expr e = evalFile(*it);
char * s;
if (ATmatch(e, "Include(<str>)", &s)) {
cout << format("%1%\n") % s;
}
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else throw badTerm("top level is not a package", e);
}
}
string programId = "fix";