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Diffstat (limited to 'src/libexpr/primops.cc')
| -rw-r--r-- | src/libexpr/primops.cc | 1336 |
1 files changed, 1336 insertions, 0 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc new file mode 100644 index 000000000000..ca316f08af13 --- /dev/null +++ b/src/libexpr/primops.cc @@ -0,0 +1,1336 @@ +#include "eval.hh" +#include "misc.hh" +#include "globals.hh" +#include "store-api.hh" +#include "util.hh" +#include "archive.hh" +#include "value-to-xml.hh" +#include "value-to-json.hh" +#include "names.hh" +#include "eval-inline.hh" + +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <algorithm> +#include <cstring> + + +namespace nix { + + +/************************************************************* + * Miscellaneous + *************************************************************/ + + +/* Decode a context string ‘!<name>!<path>’ into a pair <path, + name>. */ +std::pair<string, string> decodeContext(const string & s) +{ + if (s.at(0) == '!') { + size_t index = s.find("!", 1); + return std::pair<string, string>(string(s, index + 1), string(s, 1, index - 1)); + } else + return std::pair<string, string>(s, ""); +} + + +/* Load and evaluate an expression from path specified by the + argument. */ +static void prim_import(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[0], context); + + foreach (PathSet::iterator, i, context) { + Path ctx = decodeContext(*i).first; + assert(isStorePath(ctx)); + if (!store->isValidPath(ctx)) + throw EvalError(format("cannot import `%1%', since path `%2%' is not valid") + % path % ctx); + if (isDerivation(ctx)) + try { + /* For performance, prefetch all substitute info. */ + PathSet willBuild, willSubstitute, unknown; + unsigned long long downloadSize, narSize; + queryMissing(*store, singleton<PathSet>(ctx), + willBuild, willSubstitute, unknown, downloadSize, narSize); + + /* !!! If using a substitute, we only need to fetch + the selected output of this derivation. */ + store->buildPaths(singleton<PathSet>(ctx)); + } catch (Error & e) { + throw ImportError(e.msg()); + } + } + + if (isStorePath(path) && store->isValidPath(path) && isDerivation(path)) { + Derivation drv = parseDerivation(readFile(path)); + Value & w = *state.allocValue(); + state.mkAttrs(w, 1 + drv.outputs.size()); + mkString(*state.allocAttr(w, state.sDrvPath), path, singleton<PathSet>("=" + path)); + state.mkList(*state.allocAttr(w, state.symbols.create("outputs")), drv.outputs.size()); + unsigned int outputs_index = 0; + + Value * outputsVal = w.attrs->find(state.symbols.create("outputs"))->value; + foreach (DerivationOutputs::iterator, i, drv.outputs) { + mkString(*state.allocAttr(w, state.symbols.create(i->first)), + i->second.path, singleton<PathSet>("!" + i->first + "!" + path)); + mkString(*(outputsVal->list.elems[outputs_index++] = state.allocValue()), + i->first); + } + w.attrs->sort(); + Value fun; + state.evalFile(state.findFile("nix/imported-drv-to-derivation.nix"), fun); + state.forceFunction(fun); + mkApp(v, fun, w); + state.forceAttrs(v); + } else { + state.evalFile(path, v); + } +} + + +/* Return a string representing the type of the expression. */ +static void prim_typeOf(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + string t; + switch (args[0]->type) { + case tInt: t = "int"; break; + case tBool: t = "bool"; break; + case tString: t = "string"; break; + case tPath: t = "path"; break; + case tNull: t = "null"; break; + case tAttrs: t = "set"; break; + case tList: t = "list"; break; + case tLambda: + case tPrimOp: + case tPrimOpApp: + t = "lambda"; + break; + default: abort(); + } + mkString(v, state.symbols.create(t)); +} + + +/* Determine whether the argument is the null value. */ +static void prim_isNull(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tNull); +} + + +/* Determine whether the argument is a function. */ +static void prim_isFunction(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tLambda); +} + + +/* Determine whether the argument is an integer. */ +static void prim_isInt(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tInt); +} + + +/* Determine whether the argument is a string. */ +static void prim_isString(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tString); +} + + +/* Determine whether the argument is a Boolean. */ +static void prim_isBool(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tBool); +} + + +struct CompareValues +{ + bool operator () (const Value * v1, const Value * v2) const + { + if (v1->type != v2->type) + throw EvalError("cannot compare values of different types"); + switch (v1->type) { + case tInt: + return v1->integer < v2->integer; + case tString: + return strcmp(v1->string.s, v2->string.s) < 0; + case tPath: + return strcmp(v1->path, v2->path) < 0; + default: + throw EvalError(format("cannot compare %1% with %2%") % showType(*v1) % showType(*v2)); + } + } +}; + + +#if HAVE_BOEHMGC +typedef list<Value *, gc_allocator<Value *> > ValueList; +#else +typedef list<Value *> ValueList; +#endif + + +static void prim_genericClosure(EvalState & state, Value * * args, Value & v) +{ + startNest(nest, lvlDebug, "finding dependencies"); + + state.forceAttrs(*args[0]); + + /* Get the start set. */ + Bindings::iterator startSet = + args[0]->attrs->find(state.symbols.create("startSet")); + if (startSet == args[0]->attrs->end()) + throw EvalError("attribute `startSet' required"); + state.forceList(*startSet->value); + + ValueList workSet; + for (unsigned int n = 0; n < startSet->value->list.length; ++n) + workSet.push_back(startSet->value->list.elems[n]); + + /* Get the operator. */ + Bindings::iterator op = + args[0]->attrs->find(state.symbols.create("operator")); + if (op == args[0]->attrs->end()) + throw EvalError("attribute `operator' required"); + state.forceValue(*op->value); + + /* Construct the closure by applying the operator to element of + `workSet', adding the result to `workSet', continuing until + no new elements are found. */ + ValueList res; + // `doneKeys' doesn't need to be a GC root, because its values are + // reachable from res. + set<Value *, CompareValues> doneKeys; + while (!workSet.empty()) { + Value * e = *(workSet.begin()); + workSet.pop_front(); + + state.forceAttrs(*e); + + Bindings::iterator key = + e->attrs->find(state.symbols.create("key")); + if (key == e->attrs->end()) + throw EvalError("attribute `key' required"); + state.forceValue(*key->value); + + if (doneKeys.find(key->value) != doneKeys.end()) continue; + doneKeys.insert(key->value); + res.push_back(e); + + /* Call the `operator' function with `e' as argument. */ + Value call; + mkApp(call, *op->value, *e); + state.forceList(call); + + /* Add the values returned by the operator to the work set. */ + for (unsigned int n = 0; n < call.list.length; ++n) { + state.forceValue(*call.list.elems[n]); + workSet.push_back(call.list.elems[n]); + } + } + + /* Create the result list. */ + state.mkList(v, res.size()); + unsigned int n = 0; + foreach (ValueList::iterator, i, res) + v.list.elems[n++] = *i; +} + + +static void prim_abort(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + throw Abort(format("evaluation aborted with the following error message: `%1%'") % + state.coerceToString(*args[0], context)); +} + + +static void prim_throw(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + throw ThrownError(format("%1%") % state.coerceToString(*args[0], context)); +} + + +static void prim_addErrorContext(EvalState & state, Value * * args, Value & v) +{ + try { + state.forceValue(*args[1]); + v = *args[1]; + } catch (Error & e) { + PathSet context; + e.addPrefix(format("%1%\n") % state.coerceToString(*args[0], context)); + throw; + } +} + + +/* Try evaluating the argument. Success => {success=true; value=something;}, + * else => {success=false; value=false;} */ +static void prim_tryEval(EvalState & state, Value * * args, Value & v) +{ + state.mkAttrs(v, 2); + try { + state.forceValue(*args[0]); + v.attrs->push_back(Attr(state.sValue, args[0])); + mkBool(*state.allocAttr(v, state.symbols.create("success")), true); + } catch (AssertionError & e) { + mkBool(*state.allocAttr(v, state.sValue), false); + mkBool(*state.allocAttr(v, state.symbols.create("success")), false); + } + v.attrs->sort(); +} + + +/* Return an environment variable. Use with care. */ +static void prim_getEnv(EvalState & state, Value * * args, Value & v) +{ + string name = state.forceStringNoCtx(*args[0]); + mkString(v, getEnv(name)); +} + + +/* Evaluate the first expression and print it on standard error. Then + return the second expression. Useful for debugging. */ +static void prim_trace(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + if (args[0]->type == tString) + printMsg(lvlError, format("trace: %1%") % args[0]->string.s); + else + printMsg(lvlError, format("trace: %1%") % *args[0]); + state.forceValue(*args[1]); + v = *args[1]; +} + + +/************************************************************* + * Derivations + *************************************************************/ + + +/* 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. */ +static void prim_derivationStrict(EvalState & state, Value * * args, Value & v) +{ + startNest(nest, lvlVomit, "evaluating derivation"); + + state.forceAttrs(*args[0]); + + /* Figure out the name first (for stack backtraces). */ + Bindings::iterator attr = args[0]->attrs->find(state.sName); + if (attr == args[0]->attrs->end()) + throw EvalError("required attribute `name' missing"); + string drvName; + Pos & posDrvName(*attr->pos); + try { + drvName = state.forceStringNoCtx(*attr->value); + } catch (Error & e) { + e.addPrefix(format("while evaluating the derivation attribute `name' at %1%:\n") % posDrvName); + throw; + } + + /* Check whether null attributes should be ignored. */ + bool ignoreNulls = false; + attr = args[0]->attrs->find(state.sIgnoreNulls); + if (attr != args[0]->attrs->end()) + ignoreNulls = state.forceBool(*attr->value); + + /* Build the derivation expression by processing the attributes. */ + Derivation drv; + + PathSet context; + + string outputHash, outputHashAlgo; + bool outputHashRecursive = false; + + StringSet outputs; + outputs.insert("out"); + + foreach (Bindings::iterator, i, *args[0]->attrs) { + if (i->name == state.sIgnoreNulls) continue; + string key = i->name; + startNest(nest, lvlVomit, format("processing attribute `%1%'") % key); + + try { + + if (ignoreNulls) { + state.forceValue(*i->value); + if (i->value->type == tNull) continue; + } + + /* The `args' attribute is special: it supplies the + command-line arguments to the builder. */ + if (key == "args") { + state.forceList(*i->value); + for (unsigned int n = 0; n < i->value->list.length; ++n) { + string s = state.coerceToString(*i->value->list.elems[n], context, true); + drv.args.push_back(s); + } + } + + /* All other attributes are passed to the builder through + the environment. */ + else { + string s = state.coerceToString(*i->value, context, true); + drv.env[key] = s; + if (key == "builder") drv.builder = s; + else if (i->name == state.sSystem) drv.platform = s; + else if (i->name == state.sName) { + drvName = s; + printMsg(lvlVomit, format("derivation name is `%1%'") % drvName); + } + else if (key == "outputHash") outputHash = s; + else if (key == "outputHashAlgo") outputHashAlgo = s; + else if (key == "outputHashMode") { + if (s == "recursive") outputHashRecursive = true; + else if (s == "flat") outputHashRecursive = false; + else throw EvalError(format("invalid value `%1%' for `outputHashMode' attribute") % s); + } + else if (key == "outputs") { + Strings tmp = tokenizeString<Strings>(s); + outputs.clear(); + foreach (Strings::iterator, j, tmp) { + if (outputs.find(*j) != outputs.end()) + throw EvalError(format("duplicate derivation output `%1%'") % *j); + /* !!! Check whether *j is a valid attribute + name. */ + /* Derivations cannot be named ‘drv’, because + then we'd have an attribute ‘drvPath’ in + the resulting set. */ + if (*j == "drv") + throw EvalError(format("invalid derivation output name `drv'") % *j); + outputs.insert(*j); + } + if (outputs.empty()) + throw EvalError("derivation cannot have an empty set of outputs"); + } + } + + } catch (Error & e) { + e.addPrefix(format("while evaluating the attribute `%1%' of the derivation `%2%' at %3%:\n") + % key % drvName % posDrvName); + throw; + } + } + + /* Everything in the context of the strings in the derivation + attributes should be added as dependencies of the resulting + derivation. */ + foreach (PathSet::iterator, i, context) { + Path path = *i; + + /* Paths marked with `=' denote that the path of a derivation + is explicitly passed to the builder. Since that allows the + builder to gain access to every path in the dependency + graph of the derivation (including all outputs), all paths + in the graph must be added to this derivation's list of + inputs to ensure that they are available when the builder + runs. */ + if (path.at(0) == '=') { + /* !!! This doesn't work if readOnlyMode is set. */ + PathSet refs; computeFSClosure(*store, string(path, 1), refs); + foreach (PathSet::iterator, j, refs) { + drv.inputSrcs.insert(*j); + if (isDerivation(*j)) + drv.inputDrvs[*j] = store->queryDerivationOutputNames(*j); + } + } + + /* See prim_unsafeDiscardOutputDependency. */ + else if (path.at(0) == '~') + drv.inputSrcs.insert(string(path, 1)); + + /* Handle derivation outputs of the form ‘!<name>!<path>’. */ + else if (path.at(0) == '!') { + std::pair<string, string> ctx = decodeContext(path); + drv.inputDrvs[ctx.first].insert(ctx.second); + } + + /* Handle derivation contexts returned by + ‘builtins.storePath’. */ + else if (isDerivation(path)) + drv.inputDrvs[path] = store->queryDerivationOutputNames(path); + + /* Otherwise it's a source file. */ + else + drv.inputSrcs.insert(path); + } + + /* Do we have all required attributes? */ + if (drv.builder == "") + throw EvalError("required attribute `builder' missing"); + if (drv.platform == "") + throw EvalError("required attribute `system' missing"); + + /* Check whether the derivation name is valid. */ + checkStoreName(drvName); + if (isDerivation(drvName)) + throw EvalError(format("derivation names are not allowed to end in `%1%'") + % drvExtension); + + if (outputHash != "") { + /* Handle fixed-output derivations. */ + if (outputs.size() != 1 || *(outputs.begin()) != "out") + throw Error("multiple outputs are not supported in fixed-output derivations"); + + HashType ht = parseHashType(outputHashAlgo); + if (ht == htUnknown) + throw EvalError(format("unknown hash algorithm `%1%'") % outputHashAlgo); + Hash h = parseHash16or32(ht, outputHash); + outputHash = printHash(h); + if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo; + + Path outPath = makeFixedOutputPath(outputHashRecursive, ht, h, drvName); + drv.env["out"] = outPath; + drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, outputHash); + } + + else { + /* Construct the "masked" store derivation, which is the final + one except that in the list of outputs, the output paths + are empty, and the corresponding environment variables have + an empty value. This ensures that changes in the set of + output names do get reflected in the hash. */ + foreach (StringSet::iterator, i, outputs) { + drv.env[*i] = ""; + drv.outputs[*i] = DerivationOutput("", "", ""); + } + + /* Use the masked derivation expression to compute the output + path. */ + Hash h = hashDerivationModulo(*store, drv); + + foreach (DerivationOutputs::iterator, i, drv.outputs) + if (i->second.path == "") { + Path outPath = makeOutputPath(i->first, h, drvName); + drv.env[i->first] = outPath; + i->second.path = outPath; + } + } + + /* Write the resulting term into the Nix store directory. */ + Path drvPath = writeDerivation(*store, drv, drvName, state.repair); + + printMsg(lvlChatty, format("instantiated `%1%' -> `%2%'") + % drvName % drvPath); + + /* Optimisation, but required in read-only mode! because in that + case we don't actually write store derivations, so we can't + read them later. */ + drvHashes[drvPath] = hashDerivationModulo(*store, drv); + + state.mkAttrs(v, 1 + drv.outputs.size()); + mkString(*state.allocAttr(v, state.sDrvPath), drvPath, singleton<PathSet>("=" + drvPath)); + foreach (DerivationOutputs::iterator, i, drv.outputs) { + mkString(*state.allocAttr(v, state.symbols.create(i->first)), + i->second.path, singleton<PathSet>("!" + i->first + "!" + drvPath)); + } + v.attrs->sort(); +} + + +/************************************************************* + * Paths + *************************************************************/ + + +/* Convert the argument to a path. !!! obsolete? */ +static void prim_toPath(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[0], context); + mkString(v, canonPath(path), context); +} + + +/* Allow a valid store path to be used in an expression. This is + useful in some generated expressions such as in nix-push, which + generates a call to a function with an already existing store path + as argument. You don't want to use `toPath' here because it copies + the path to the Nix store, which yields a copy like + /nix/store/newhash-oldhash-oldname. In the past, `toPath' had + special case behaviour for store paths, but that created weird + corner cases. */ +static void prim_storePath(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[0], context); + /* Resolve symlinks in ‘path’, unless ‘path’ itself is a symlink + directly in the store. The latter condition is necessary so + e.g. nix-push does the right thing. */ + if (!isStorePath(path)) path = canonPath(path, true); + if (!isInStore(path)) + throw EvalError(format("path `%1%' is not in the Nix store") % path); + Path path2 = toStorePath(path); + if (!settings.readOnlyMode) + store->ensurePath(path2); + context.insert(path2); + mkString(v, path, context); +} + + +static void prim_pathExists(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[0], context); + if (!context.empty()) + throw EvalError(format("string `%1%' cannot refer to other paths") % path); + mkBool(v, pathExists(path)); +} + + +/* Return the base name of the given string, i.e., everything + following the last slash. */ +static void prim_baseNameOf(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + mkString(v, baseNameOf(state.coerceToString(*args[0], context)), context); +} + + +/* Return the directory of the given path, i.e., everything before the + last slash. Return either a path or a string depending on the type + of the argument. */ +static void prim_dirOf(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path dir = dirOf(state.coerceToPath(*args[0], context)); + if (args[0]->type == tPath) mkPath(v, dir.c_str()); else mkString(v, dir, context); +} + + +/* Return the contents of a file as a string. */ +static void prim_readFile(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[0], context); + if (!context.empty()) + throw EvalError(format("string `%1%' cannot refer to other paths") % path); + mkString(v, readFile(path).c_str()); +} + + +/************************************************************* + * Creating files + *************************************************************/ + + +/* Convert the argument (which can be any Nix expression) to an XML + representation returned in a string. Not all Nix expressions can + be sensibly or completely represented (e.g., functions). */ +static void prim_toXML(EvalState & state, Value * * args, Value & v) +{ + std::ostringstream out; + PathSet context; + printValueAsXML(state, true, false, *args[0], out, context); + mkString(v, out.str(), context); +} + + +/* Convert the argument (which can be any Nix expression) to a JSON + string. Not all Nix expressions can be sensibly or completely + represented (e.g., functions). */ +static void prim_toJSON(EvalState & state, Value * * args, Value & v) +{ + std::ostringstream out; + PathSet context; + printValueAsJSON(state, true, *args[0], out, context); + mkString(v, out.str(), context); +} + + +/* Store a string in the Nix store as a source file that can be used + as an input by derivations. */ +static void prim_toFile(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + string name = state.forceStringNoCtx(*args[0]); + string contents = state.forceString(*args[1], context); + + PathSet refs; + + foreach (PathSet::iterator, i, context) { + Path path = *i; + if (path.at(0) == '=') path = string(path, 1); + if (isDerivation(path)) + throw EvalError(format("in `toFile': the file `%1%' cannot refer to derivation outputs") % name); + refs.insert(path); + } + + Path storePath = settings.readOnlyMode + ? computeStorePathForText(name, contents, refs) + : store->addTextToStore(name, contents, refs, state.repair); + + /* Note: we don't need to add `context' to the context of the + result, since `storePath' itself has references to the paths + used in args[1]. */ + + mkString(v, storePath, singleton<PathSet>(storePath)); +} + + +struct FilterFromExpr : PathFilter +{ + EvalState & state; + Value & filter; + + FilterFromExpr(EvalState & state, Value & filter) + : state(state), filter(filter) + { + } + + bool operator () (const Path & path) + { + struct stat st; + if (lstat(path.c_str(), &st)) + throw SysError(format("getting attributes of path `%1%'") % path); + + /* Call the filter function. The first argument is the path, + the second is a string indicating the type of the file. */ + Value arg1; + mkString(arg1, path); + + Value fun2; + state.callFunction(filter, arg1, fun2); + + Value arg2; + mkString(arg2, + S_ISREG(st.st_mode) ? "regular" : + S_ISDIR(st.st_mode) ? "directory" : + S_ISLNK(st.st_mode) ? "symlink" : + "unknown" /* not supported, will fail! */); + + Value res; + state.callFunction(fun2, arg2, res); + + return state.forceBool(res); + } +}; + + +static void prim_filterSource(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + Path path = state.coerceToPath(*args[1], context); + if (!context.empty()) + throw EvalError(format("string `%1%' cannot refer to other paths") % path); + + state.forceValue(*args[0]); + if (args[0]->type != tLambda) + throw TypeError(format("first argument in call to `filterSource' is not a function but %1%") % showType(*args[0])); + + FilterFromExpr filter(state, *args[0]); + + Path dstPath = settings.readOnlyMode + ? computeStorePathForPath(path, true, htSHA256, filter).first + : store->addToStore(path, true, htSHA256, filter, state.repair); + + mkString(v, dstPath, singleton<PathSet>(dstPath)); +} + + +/************************************************************* + * Sets + *************************************************************/ + + +/* Return the names of the attributes in a set as a sorted list of + strings. */ +static void prim_attrNames(EvalState & state, Value * * args, Value & v) +{ + state.forceAttrs(*args[0]); + + state.mkList(v, args[0]->attrs->size()); + + StringSet names; + foreach (Bindings::iterator, i, *args[0]->attrs) + names.insert(i->name); + + unsigned int n = 0; + foreach (StringSet::iterator, i, names) + mkString(*(v.list.elems[n++] = state.allocValue()), *i); +} + + +/* Dynamic version of the `.' operator. */ +void prim_getAttr(EvalState & state, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0]); + state.forceAttrs(*args[1]); + // !!! Should we create a symbol here or just do a lookup? + Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr)); + if (i == args[1]->attrs->end()) + throw EvalError(format("attribute `%1%' missing") % attr); + // !!! add to stack trace? + if (state.countCalls && i->pos) state.attrSelects[*i->pos]++; + state.forceValue(*i->value); + v = *i->value; +} + + +/* Return position information of the specified attribute. */ +void prim_unsafeGetAttrPos(EvalState & state, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0]); + state.forceAttrs(*args[1]); + Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr)); + if (i == args[1]->attrs->end()) + mkNull(v); + else + state.mkPos(v, i->pos); +} + + +/* Dynamic version of the `?' operator. */ +static void prim_hasAttr(EvalState & state, Value * * args, Value & v) +{ + string attr = state.forceStringNoCtx(*args[0]); + state.forceAttrs(*args[1]); + mkBool(v, args[1]->attrs->find(state.symbols.create(attr)) != args[1]->attrs->end()); +} + + +/* Determine whether the argument is a set. */ +static void prim_isAttrs(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tAttrs); +} + + +static void prim_removeAttrs(EvalState & state, Value * * args, Value & v) +{ + state.forceAttrs(*args[0]); + state.forceList(*args[1]); + + /* Get the attribute names to be removed. */ + std::set<Symbol> names; + for (unsigned int i = 0; i < args[1]->list.length; ++i) { + state.forceStringNoCtx(*args[1]->list.elems[i]); + names.insert(state.symbols.create(args[1]->list.elems[i]->string.s)); + } + + /* Copy all attributes not in that set. Note that we don't need + to sort v.attrs because it's a subset of an already sorted + vector. */ + state.mkAttrs(v, args[0]->attrs->size()); + foreach (Bindings::iterator, i, *args[0]->attrs) { + if (names.find(i->name) == names.end()) + v.attrs->push_back(*i); + } +} + + +/* Builds a set from a list specifying (name, value) pairs. To be + precise, a list [{name = "name1"; value = value1;} ... {name = + "nameN"; value = valueN;}] is transformed to {name1 = value1; + ... nameN = valueN;}. In case of duplicate occurences of the same + name, the first takes precedence. */ +static void prim_listToAttrs(EvalState & state, Value * * args, Value & v) +{ + state.forceList(*args[0]); + + state.mkAttrs(v, args[0]->list.length); + + std::set<Symbol> seen; + + for (unsigned int i = 0; i < args[0]->list.length; ++i) { + Value & v2(*args[0]->list.elems[i]); + state.forceAttrs(v2); + + Bindings::iterator j = v2.attrs->find(state.sName); + if (j == v2.attrs->end()) + throw TypeError("`name' attribute missing in a call to `listToAttrs'"); + string name = state.forceStringNoCtx(*j->value); + + Symbol sym = state.symbols.create(name); + if (seen.find(sym) == seen.end()) { + Bindings::iterator j2 = v2.attrs->find(state.symbols.create(state.sValue)); + if (j2 == v2.attrs->end()) + throw TypeError("`value' attribute missing in a call to `listToAttrs'"); + + v.attrs->push_back(Attr(sym, j2->value, j2->pos)); + seen.insert(sym); + } + } + + v.attrs->sort(); +} + + +/* Return the right-biased intersection of two sets as1 and as2, + i.e. a set that contains every attribute from as2 that is also a + member of as1. */ +static void prim_intersectAttrs(EvalState & state, Value * * args, Value & v) +{ + state.forceAttrs(*args[0]); + state.forceAttrs(*args[1]); + + state.mkAttrs(v, std::min(args[0]->attrs->size(), args[1]->attrs->size())); + + foreach (Bindings::iterator, i, *args[0]->attrs) { + Bindings::iterator j = args[1]->attrs->find(i->name); + if (j != args[1]->attrs->end()) + v.attrs->push_back(*j); + } +} + + +/* Return a set containing the names of the formal arguments expected + by the function `f'. The value of each attribute is a Boolean + denoting whether has a default value. For instance, + + functionArgs ({ x, y ? 123}: ...) + => { x = false; y = true; } + + "Formal argument" here refers to the attributes pattern-matched by + the function. Plain lambdas are not included, e.g. + + functionArgs (x: ...) + => { } +*/ +static void prim_functionArgs(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + if (args[0]->type != tLambda) + throw TypeError("`functionArgs' requires a function"); + + if (!args[0]->lambda.fun->matchAttrs) { + state.mkAttrs(v, 0); + return; + } + + state.mkAttrs(v, args[0]->lambda.fun->formals->formals.size()); + foreach (Formals::Formals_::iterator, i, args[0]->lambda.fun->formals->formals) + // !!! should optimise booleans (allocate only once) + mkBool(*state.allocAttr(v, i->name), i->def); + v.attrs->sort(); +} + + +/************************************************************* + * Lists + *************************************************************/ + + +/* Determine whether the argument is a list. */ +static void prim_isList(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + mkBool(v, args[0]->type == tList); +} + + +static void elemAt(EvalState & state, Value & list, int n, Value & v) +{ + state.forceList(list); + if (n < 0 || n >= list.list.length) + throw Error(format("list index %1% is out of bounds") % n); + state.forceValue(*list.list.elems[n]); + v = *list.list.elems[n]; +} + + +/* Return the n-1'th element of a list. */ +static void prim_elemAt(EvalState & state, Value * * args, Value & v) +{ + elemAt(state, *args[0], state.forceInt(*args[1]), v); +} + + +/* Return the first element of a list. */ +static void prim_head(EvalState & state, Value * * args, Value & v) +{ + elemAt(state, *args[0], 0, v); +} + + +/* Return a list consisting of everything but the the first element of + a list. Warning: this function takes O(n) time, so you probably + don't want to use it! */ +static void prim_tail(EvalState & state, Value * * args, Value & v) +{ + state.forceList(*args[0]); + if (args[0]->list.length == 0) + throw Error("`tail' called on an empty list"); + state.mkList(v, args[0]->list.length - 1); + for (unsigned int n = 0; n < v.list.length; ++n) + v.list.elems[n] = args[0]->list.elems[n + 1]; +} + + +/* Apply a function to every element of a list. */ +static void prim_map(EvalState & state, Value * * args, Value & v) +{ + state.forceFunction(*args[0]); + state.forceList(*args[1]); + + state.mkList(v, args[1]->list.length); + + for (unsigned int n = 0; n < v.list.length; ++n) + mkApp(*(v.list.elems[n] = state.allocValue()), + *args[0], *args[1]->list.elems[n]); +} + + +/* Filter a list using a predicate; that is, return a list containing + every element from the list for which the predicate function + returns true. */ +static void prim_filter(EvalState & state, Value * * args, Value & v) +{ + state.forceFunction(*args[0]); + state.forceList(*args[1]); + + // FIXME: putting this on the stack is risky. + Value * vs[args[1]->list.length]; + unsigned int k = 0; + + bool same = true; + for (unsigned int n = 0; n < args[1]->list.length; ++n) { + Value res; + state.callFunction(*args[0], *args[1]->list.elems[n], res); + if (state.forceBool(res)) + vs[k++] = args[1]->list.elems[n]; + else + same = false; + } + + if (same) + v = *args[1]; + else { + state.mkList(v, k); + for (unsigned int n = 0; n < k; ++n) v.list.elems[n] = vs[n]; + } +} + + +/* Return true if a list contains a given element. */ +static void prim_elem(EvalState & state, Value * * args, Value & v) +{ + bool res = false; + state.forceList(*args[1]); + for (unsigned int n = 0; n < args[1]->list.length; ++n) + if (state.eqValues(*args[0], *args[1]->list.elems[n])) { + res = true; + break; + } + mkBool(v, res); +} + + +/* Concatenate a list of lists. */ +static void prim_concatLists(EvalState & state, Value * * args, Value & v) +{ + state.forceList(*args[0]); + state.concatLists(v, args[0]->list.length, args[0]->list.elems); +} + + +/* Return the length of a list. This is an O(1) time operation. */ +static void prim_length(EvalState & state, Value * * args, Value & v) +{ + state.forceList(*args[0]); + mkInt(v, args[0]->list.length); +} + + +/************************************************************* + * Integer arithmetic + *************************************************************/ + + +static void prim_add(EvalState & state, Value * * args, Value & v) +{ + mkInt(v, state.forceInt(*args[0]) + state.forceInt(*args[1])); +} + + +static void prim_sub(EvalState & state, Value * * args, Value & v) +{ + mkInt(v, state.forceInt(*args[0]) - state.forceInt(*args[1])); +} + + +static void prim_mul(EvalState & state, Value * * args, Value & v) +{ + mkInt(v, state.forceInt(*args[0]) * state.forceInt(*args[1])); +} + + +static void prim_div(EvalState & state, Value * * args, Value & v) +{ + NixInt i2 = state.forceInt(*args[1]); + if (i2 == 0) throw EvalError("division by zero"); + mkInt(v, state.forceInt(*args[0]) / i2); +} + + +static void prim_lessThan(EvalState & state, Value * * args, Value & v) +{ + state.forceValue(*args[0]); + state.forceValue(*args[1]); + CompareValues comp; + mkBool(v, comp(args[0], args[1])); +} + + +/************************************************************* + * String manipulation + *************************************************************/ + + +/* Convert the argument to a string. Paths are *not* copied to the + store, so `toString /foo/bar' yields `"/foo/bar"', not + `"/nix/store/whatever..."'. */ +static void prim_toString(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(*args[0], context, true, false); + mkString(v, s, context); +} + + +/* `substring start len str' returns the substring of `str' starting + at character position `min(start, stringLength str)' inclusive and + ending at `min(start + len, stringLength str)'. `start' must be + non-negative. */ +static void prim_substring(EvalState & state, Value * * args, Value & v) +{ + int start = state.forceInt(*args[0]); + int len = state.forceInt(*args[1]); + PathSet context; + string s = state.coerceToString(*args[2], context); + + if (start < 0) throw EvalError("negative start position in `substring'"); + + mkString(v, start >= s.size() ? "" : string(s, start, len), context); +} + + +static void prim_stringLength(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(*args[0], context); + mkInt(v, s.size()); +} + + +static void prim_unsafeDiscardStringContext(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(*args[0], context); + mkString(v, s, PathSet()); +} + + +/* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a + builder without causing the derivation to be built (for instance, + in the derivation that builds NARs in nix-push, when doing + source-only deployment). This primop marks the string context so + that builtins.derivation adds the path to drv.inputSrcs rather than + drv.inputDrvs. */ +static void prim_unsafeDiscardOutputDependency(EvalState & state, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(*args[0], context); + + PathSet context2; + foreach (PathSet::iterator, i, context) { + Path p = *i; + if (p.at(0) == '=') p = "~" + string(p, 1); + context2.insert(p); + } + + mkString(v, s, context2); +} + + +/* Return the cryptographic hash of a string in base-16. */ +static void prim_hashString(EvalState & state, Value * * args, Value & v) +{ + string type = state.forceStringNoCtx(*args[0]); + HashType ht = parseHashType(type); + if (ht == htUnknown) + throw Error(format("unknown hash type `%1%'") % type); + + PathSet context; // discarded + string s = state.forceString(*args[1], context); + + mkString(v, printHash(hashString(ht, s)), context); +}; + + +/************************************************************* + * Versions + *************************************************************/ + + +static void prim_parseDrvName(EvalState & state, Value * * args, Value & v) +{ + string name = state.forceStringNoCtx(*args[0]); + DrvName parsed(name); + state.mkAttrs(v, 2); + mkString(*state.allocAttr(v, state.sName), parsed.name); + mkString(*state.allocAttr(v, state.symbols.create("version")), parsed.version); + v.attrs->sort(); +} + + +static void prim_compareVersions(EvalState & state, Value * * args, Value & v) +{ + string version1 = state.forceStringNoCtx(*args[0]); + string version2 = state.forceStringNoCtx(*args[1]); + mkInt(v, compareVersions(version1, version2)); +} + + +/************************************************************* + * Primop registration + *************************************************************/ + + +void EvalState::createBaseEnv() +{ + baseEnv.up = 0; + + /* Add global constants such as `true' to the base environment. */ + Value v; + + /* `builtins' must be first! */ + mkAttrs(v, 128); + addConstant("builtins", v); + + mkBool(v, true); + addConstant("true", v); + + mkBool(v, false); + addConstant("false", v); + + mkNull(v); + addConstant("null", v); + + mkInt(v, time(0)); + addConstant("__currentTime", v); + + mkString(v, settings.thisSystem.c_str()); + addConstant("__currentSystem", v); + + mkString(v, nixVersion.c_str()); + addConstant("__nixVersion", v); + + /* Language version. This should be increased every time a new + language feature gets added. It's not necessary to increase it + when primops get added, because you can just use `builtins ? + primOp' to check. */ + mkInt(v, 2); + addConstant("__langVersion", v); + + // Miscellaneous + addPrimOp("import", 1, prim_import); + addPrimOp("__typeOf", 1, prim_typeOf); + addPrimOp("isNull", 1, prim_isNull); + addPrimOp("__isFunction", 1, prim_isFunction); + addPrimOp("__isString", 1, prim_isString); + addPrimOp("__isInt", 1, prim_isInt); + addPrimOp("__isBool", 1, prim_isBool); + addPrimOp("__genericClosure", 1, prim_genericClosure); + addPrimOp("abort", 1, prim_abort); + addPrimOp("throw", 1, prim_throw); + addPrimOp("__addErrorContext", 2, prim_addErrorContext); + addPrimOp("__tryEval", 1, prim_tryEval); + addPrimOp("__getEnv", 1, prim_getEnv); + addPrimOp("__trace", 2, prim_trace); + + // Paths + addPrimOp("__toPath", 1, prim_toPath); + addPrimOp("__storePath", 1, prim_storePath); + addPrimOp("__pathExists", 1, prim_pathExists); + addPrimOp("baseNameOf", 1, prim_baseNameOf); + addPrimOp("dirOf", 1, prim_dirOf); + addPrimOp("__readFile", 1, prim_readFile); + + // Creating files + addPrimOp("__toXML", 1, prim_toXML); + addPrimOp("__toJSON", 1, prim_toJSON); + addPrimOp("__toFile", 2, prim_toFile); + addPrimOp("__filterSource", 2, prim_filterSource); + + // Sets + addPrimOp("__attrNames", 1, prim_attrNames); + addPrimOp("__getAttr", 2, prim_getAttr); + addPrimOp("__unsafeGetAttrPos", 2, prim_unsafeGetAttrPos); + addPrimOp("__hasAttr", 2, prim_hasAttr); + addPrimOp("__isAttrs", 1, prim_isAttrs); + addPrimOp("removeAttrs", 2, prim_removeAttrs); + addPrimOp("__listToAttrs", 1, prim_listToAttrs); + addPrimOp("__intersectAttrs", 2, prim_intersectAttrs); + addPrimOp("__functionArgs", 1, prim_functionArgs); + + // Lists + addPrimOp("__isList", 1, prim_isList); + addPrimOp("__elemAt", 2, prim_elemAt); + addPrimOp("__head", 1, prim_head); + addPrimOp("__tail", 1, prim_tail); + addPrimOp("map", 2, prim_map); + addPrimOp("__filter", 2, prim_filter); + addPrimOp("__elem", 2, prim_elem); + addPrimOp("__concatLists", 1, prim_concatLists); + addPrimOp("__length", 1, prim_length); + + // Integer arithmetic + addPrimOp("__add", 2, prim_add); + addPrimOp("__sub", 2, prim_sub); + addPrimOp("__mul", 2, prim_mul); + addPrimOp("__div", 2, prim_div); + addPrimOp("__lessThan", 2, prim_lessThan); + + // String manipulation + addPrimOp("toString", 1, prim_toString); + addPrimOp("__substring", 3, prim_substring); + addPrimOp("__stringLength", 1, prim_stringLength); + addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext); + addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency); + addPrimOp("__hashString", 2, prim_hashString); + + // Versions + addPrimOp("__parseDrvName", 1, prim_parseDrvName); + addPrimOp("__compareVersions", 2, prim_compareVersions); + + // Derivations + addPrimOp("derivationStrict", 1, prim_derivationStrict); + + /* Add a wrapper around the derivation primop that computes the + `drvPath' and `outPath' attributes lazily. */ + string path = findFile("nix/derivation.nix"); + assert(!path.empty()); + sDerivationNix = symbols.create(path); + evalFile(path, v); + addConstant("derivation", v); + + /* Now that we've added all primops, sort the `builtins' set, + because attribute lookups expect it to be sorted. */ + baseEnv.values[0]->attrs->sort(); +} + + +} |