lix/src/fix.cc

485 lines
13 KiB
C++

#include <map>
#include <iostream>
#include "globals.hh"
#include "normalise.hh"
#include "shared.hh"
typedef ATerm Expr;
typedef map<ATerm, ATerm> NormalForms;
typedef map<Path, PathSet> PkgPaths;
typedef map<Path, Hash> PkgHashes;
struct EvalState
{
Paths searchDirs;
NormalForms normalForms;
PkgPaths pkgPaths;
PkgHashes pkgHashes; /* normalised package hashes */
Expr blackHole;
EvalState()
{
blackHole = ATmake("BlackHole()");
if (!blackHole) throw Error("cannot build black hole");
}
};
static Expr evalFile(EvalState & state, const Path & path);
static Expr evalExpr(EvalState & state, Expr e);
static Path searchPath(const Paths & searchDirs, const Path & relPath)
{
if (string(relPath, 0, 1) == "/") return relPath;
for (Paths::const_iterator i = searchDirs.begin();
i != searchDirs.end(); i++)
{
Path path = *i + "/" + relPath;
if (pathExists(path)) return path;
}
throw Error(
format("path `%1%' not found in any of the search directories")
% relPath);
}
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);
}
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);
Expr x;
if (ATmatch(e1, "True")) x = e2;
else if (ATmatch(e1, "False")) x = e3;
else throw badTerm("expecting a boolean", e1);
return evalExpr(state, x);
}
/* Ad-hoc function for string matching. */
if (ATmatch(e, "HasSubstr(<term>, <term>)", &e1, &e2)) {
e1 = evalExpr(state, e1);
e2 = evalExpr(state, e2);
char * s1, * s2;
if (!ATmatch(e1, "<str>", &s1))
throw badTerm("expecting a string", e1);
if (!ATmatch(e2, "<str>", &s2))
throw badTerm("expecting a string", e2);
return
string(s1).find(string(s2)) != string::npos ?
ATmake("True") : ATmake("False");
}
/* Platform constant. */
if (ATmatch(e, "Platform")) {
return ATmake("<str>", SYSTEM);
}
/* 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 = searchPath(state.searchDirs, 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>", SYSTEM);
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 = SYSTEM;
string name;
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 == "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);
/* Hash the Nix expression with no outputs to produce a
unique but deterministic path name for this package. */
if (!outHashGiven) outHash = hashPackage(state, ne);
Path 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);
if (!ATmatch(e1, "<str>", &s1))
throw badTerm("string expected", e1);
return ATmake("<str>", baseNameOf(s1).c_str());
}
/* Barf. */
throw badTerm("invalid expression", e);
}
static Expr evalExpr(EvalState & state, Expr e)
{
Nest nest(lvlVomit, format("evaluating expression: %1%") % printTerm(e));
/* 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);
return i->second;
}
/* Otherwise, evaluate and memoize. */
state.normalForms[e] = state.blackHole;
Expr nf = evalExpr2(state, e);
state.normalForms[e] = nf;
return nf;
}
static Expr evalFile(EvalState & state, const Path & relPath)
{
Path path = searchPath(state.searchDirs, relPath);
Nest nest(lvlTalkative, format("evaluating file `%1%'") % path);
Expr e = ATreadFromNamedFile(path.c_str());
if (!e)
throw Error(format("unable to read a term from `%1%'") % path);
return evalExpr(state, e);
}
static Expr evalStdin(EvalState & state)
{
Nest nest(lvlTalkative, format("evaluating standard input"));
Expr e = ATreadFromFile(stdin);
if (!e)
throw Error(format("unable to read a term from stdin"));
return evalExpr(state, e);
}
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)) {
while (!ATisEmpty(es)) {
printNixExpr(state, evalExpr(state, ATgetFirst(es)));
es = ATgetNext(es);
}
}
else throw badTerm("top level does not evaluate to a (list of) Nix expression(s)", e);
}
void run(Strings args)
{
EvalState state;
Strings files;
bool readStdin = false;
state.searchDirs.push_back(".");
state.searchDirs.push_back(nixDataDir + "/fix");
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);
state.searchDirs.push_back(*it++);
}
else if (arg == "--verbose" || arg == "-v")
verbosity = (Verbosity) ((int) verbosity + 1);
else if (arg == "-")
readStdin = true;
else if (arg[0] == '-')
throw UsageError(format("unknown flag `%1%`") % arg);
else
files.push_back(arg);
}
openDB();
if (readStdin) {
Expr e = evalStdin(state);
printNixExpr(state, e);
}
for (Strings::iterator it = files.begin();
it != files.end(); it++)
{
Expr e = evalFile(state, *it);
printNixExpr(state, e);
}
}
string programId = "fix";