diff options
Diffstat (limited to 'src/fix/fix.cc')
| -rw-r--r-- | src/fix/fix.cc | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/src/fix/fix.cc b/src/fix/fix.cc new file mode 100644 index 000000000..c1f9c1ad6 --- /dev/null +++ b/src/fix/fix.cc @@ -0,0 +1,488 @@ +#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; + 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); + 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"; |