lix/src/libexpr/primops.cc
Eelco Dolstra e4b0666f8e * builtins.filterSource: pass the type of the file ("regular",
"directory", "symlink") as the second argument to the filter
  predicate.
2007-01-15 08:54:51 +00:00

823 lines
26 KiB
C++

#include "misc.hh"
#include "eval.hh"
#include "globals.hh"
#include "store-api.hh"
#include "util.hh"
#include "archive.hh"
#include "expr-to-xml.hh"
#include "nixexpr-ast.hh"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <algorithm>
namespace nix {
static Expr primBuiltins(EvalState & state, const ATermVector & args)
{
/* Return an attribute set containing all primops. This allows
Nix expressions to test for new primops and take appropriate
action if they're not available. For instance, rather than
calling a primop `foo' directly, they could say `if builtins ?
foo then builtins.foo ... else ...'. */
ATermMap builtins(state.primOps.size());
for (ATermMap::const_iterator i = state.primOps.begin();
i != state.primOps.end(); ++i)
{
string name = aterm2String(i->key);
if (string(name, 0, 2) == "__")
name = string(name, 2);
/* !!! should use makePrimOp here, I guess. */
builtins.set(toATerm(name), makeAttrRHS(makeVar(i->key), makeNoPos()));
}
return makeAttrs(builtins);
}
/* Load and evaluate an expression from path specified by the
argument. */
static Expr primImport(EvalState & state, const ATermVector & args)
{
PathSet context;
Path path = coerceToPath(state, args[0], context);
for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
assert(isStorePath(*i));
if (!store->isValidPath(*i))
throw EvalError(format("cannot import `%1%', since path `%2%' is not valid")
% path % *i);
if (isDerivation(*i))
store->buildDerivations(singleton<PathSet>(*i));
}
return evalFile(state, path);
}
static Expr primPathExists(EvalState & state, const ATermVector & args)
{
PathSet context;
Path path = coerceToPath(state, args[0], context);
if (!context.empty())
throw EvalError(format("string `%1%' cannot refer to other paths") % path);
return makeBool(pathExists(path));
}
/* Returns the hash of a derivation modulo fixed-output
subderivations. A fixed-output derivation is a derivation with one
output (`out') for which an expected hash and hash algorithm are
specified (using the `outputHash' and `outputHashAlgo'
attributes). We don't want changes to such derivations to
propagate upwards through the dependency graph, changing output
paths everywhere.
For instance, if we change the url in a call to the `fetchurl'
function, we do not want to rebuild everything depending on it
(after all, (the hash of) the file being downloaded is unchanged).
So the *output paths* should not change. On the other hand, the
*derivation store expression paths* should change to reflect the
new dependency graph.
That's what this function does: it returns a hash which is just the
of the derivation ATerm, except that any input store expression
paths have been replaced by the result of a recursive call to this
function, and that for fixed-output derivations we return
(basically) its outputHash. */
static Hash hashDerivationModulo(EvalState & state, Derivation drv)
{
/* Return a fixed hash for fixed-output derivations. */
if (drv.outputs.size() == 1) {
DerivationOutputs::const_iterator i = drv.outputs.begin();
if (i->first == "out" &&
i->second.hash != "")
{
return hashString(htSHA256, "fixed:out:"
+ i->second.hashAlgo + ":"
+ i->second.hash + ":"
+ i->second.path);
}
}
/* For other derivations, replace the inputs paths with recursive
calls to this function.*/
DerivationInputs inputs2;
for (DerivationInputs::iterator i = drv.inputDrvs.begin();
i != drv.inputDrvs.end(); ++i)
{
Hash h = state.drvHashes[i->first];
if (h.type == htUnknown) {
Derivation drv2 = derivationFromPath(i->first);
h = hashDerivationModulo(state, drv2);
state.drvHashes[i->first] = h;
}
inputs2[printHash(h)] = i->second;
}
drv.inputDrvs = inputs2;
return hashTerm(unparseDerivation(drv));
}
/* 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 Expr primDerivationStrict(EvalState & state, const ATermVector & args)
{
startNest(nest, lvlVomit, "evaluating derivation");
ATermMap attrs;
queryAllAttrs(evalExpr(state, args[0]), attrs, true);
/* Figure out the name already (for stack backtraces). */
ATerm posDrvName;
Expr eDrvName = attrs.get(toATerm("name"));
if (!eDrvName)
throw EvalError("required attribute `name' missing");
if (!matchAttrRHS(eDrvName, eDrvName, posDrvName)) abort();
string drvName;
try {
drvName = evalStringNoCtx(state, eDrvName);
} catch (Error & e) {
e.addPrefix(format("while evaluating the derivation attribute `name' at %1%:\n")
% showPos(posDrvName));
throw;
}
/* Build the derivation expression by processing the attributes. */
Derivation drv;
PathSet context;
string outputHash;
string outputHashAlgo;
bool outputHashRecursive = false;
for (ATermMap::const_iterator i = attrs.begin(); i != attrs.end(); ++i) {
string key = aterm2String(i->key);
ATerm value;
Expr pos;
ATerm rhs = i->value;
if (!matchAttrRHS(rhs, value, pos)) abort();
startNest(nest, lvlVomit, format("processing attribute `%1%'") % key);
try {
/* The `args' attribute is special: it supplies the
command-line arguments to the builder. */
if (key == "args") {
ATermList es;
value = evalExpr(state, value);
if (!matchList(value, es)) {
static bool haveWarned = false;
warnOnce(haveWarned, "the `args' attribute should evaluate to a list");
es = flattenList(state, value);
}
for (ATermIterator i(es); i; ++i) {
string s = coerceToString(state, *i, context, true);
drv.args.push_back(s);
}
}
/* All other attributes are passed to the builder through
the environment. */
else {
string s = coerceToString(state, value, context, true);
drv.env[key] = s;
if (key == "builder") drv.builder = s;
else if (key == "system") drv.platform = s;
else if (key == "name") drvName = s;
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);
}
}
} catch (Error & e) {
e.addPrefix(format("while evaluating the derivation attribute `%1%' at %2%:\n")
% key % showPos(pos));
e.addPrefix(format("while instantiating the derivation named `%1%' at %2%:\n")
% drvName % showPos(posDrvName));
throw;
}
}
/* Everything in the context of the strings in the derivation
attributes should be added as dependencies of the resulting
derivation. */
for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
debug(format("derivation uses `%1%'") % *i);
assert(isStorePath(*i));
if (isDerivation(*i))
drv.inputDrvs[*i] = singleton<StringSet>("out");
else
drv.inputSrcs.insert(*i);
}
/* Do we have all required attributes? */
if (drv.builder == "")
throw EvalError("required attribute `builder' missing");
if (drv.platform == "")
throw EvalError("required attribute `system' missing");
/* If an output hash was given, check it. */
if (outputHash == "")
outputHashAlgo = "";
else {
HashType ht = parseHashType(outputHashAlgo);
if (ht == htUnknown)
throw EvalError(format("unknown hash algorithm `%1%'") % outputHashAlgo);
Hash h(ht);
if (outputHash.size() == h.hashSize * 2)
/* hexadecimal representation */
h = parseHash(ht, outputHash);
else if (outputHash.size() == hashLength32(h))
/* base-32 representation */
h = parseHash32(ht, outputHash);
else
throw Error(format("hash `%1%' has wrong length for hash type `%2%'")
% outputHash % outputHashAlgo);
string s = outputHash;
outputHash = printHash(h);
if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo;
}
/* 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);
/* Construct the "masked" derivation store expression, 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. */
drv.env["out"] = "";
drv.outputs["out"] =
DerivationOutput("", outputHashAlgo, outputHash);
/* Use the masked derivation expression to compute the output
path. */
Path outPath = makeStorePath("output:out",
hashDerivationModulo(state, drv), drvName);
/* Construct the final derivation store expression. */
drv.env["out"] = outPath;
drv.outputs["out"] =
DerivationOutput(outPath, outputHashAlgo, outputHash);
/* Write the resulting term into the Nix store directory. */
Path drvPath = writeDerivation(drv, drvName);
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 expressions, so we can't
read them later. */
state.drvHashes[drvPath] = hashDerivationModulo(state, drv);
/* !!! assumes a single output */
ATermMap outAttrs(2);
outAttrs.set(toATerm("outPath"),
makeAttrRHS(makeStr(outPath, singleton<PathSet>(drvPath)), makeNoPos()));
outAttrs.set(toATerm("drvPath"),
makeAttrRHS(makeStr(drvPath, singleton<PathSet>(drvPath)), makeNoPos()));
return makeAttrs(outAttrs);
}
static Expr primDerivationLazy(EvalState & state, const ATermVector & args)
{
Expr eAttrs = evalExpr(state, args[0]);
ATermMap attrs;
queryAllAttrs(eAttrs, attrs, true);
attrs.set(toATerm("type"),
makeAttrRHS(makeStr("derivation"), makeNoPos()));
Expr drvStrict = makeCall(makeVar(toATerm("derivation!")), eAttrs);
attrs.set(toATerm("outPath"),
makeAttrRHS(makeSelect(drvStrict, toATerm("outPath")), makeNoPos()));
attrs.set(toATerm("drvPath"),
makeAttrRHS(makeSelect(drvStrict, toATerm("drvPath")), makeNoPos()));
return makeAttrs(attrs);
}
/* Return the base name of the given string, i.e., everything
following the last slash. */
static Expr primBaseNameOf(EvalState & state, const ATermVector & args)
{
PathSet context;
return makeStr(baseNameOf(coerceToString(state, 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 Expr primDirOf(EvalState & state, const ATermVector & args)
{
PathSet context;
Expr e = evalExpr(state, args[0]); ATerm dummy;
bool isPath = matchPath(e, dummy);
Path dir = dirOf(coerceToPath(state, e, context));
return isPath ? makePath(toATerm(dir)) : makeStr(dir, context);
}
/* 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 Expr primToString(EvalState & state, const ATermVector & args)
{
PathSet context;
string s = coerceToString(state, args[0], context, true, false);
return makeStr(s, context);
}
/* Convert the argument to a path. !!! obsolete? */
static Expr primToPath(EvalState & state, const ATermVector & args)
{
PathSet context;
string path = coerceToPath(state, args[0], context);
return makeStr(canonPath(path), context);
}
/* 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 Expr primToXML(EvalState & state, const ATermVector & args)
{
std::ostringstream out;
PathSet context;
printTermAsXML(strictEvalExpr(state, args[0]), out, context);
return makeStr(out.str(), context);
}
/* Store a string in the Nix store as a source file that can be used
as an input by derivations. */
static Expr primToFile(EvalState & state, const ATermVector & args)
{
PathSet context;
string name = evalStringNoCtx(state, args[0]);
string contents = evalString(state, args[1], context);
PathSet refs;
for (PathSet::iterator i = context.begin(); i != context.end(); ++i) {
if (isDerivation(*i))
throw EvalError(format("in `toFile': the file `%1%' cannot refer to derivation outputs") % name);
refs.insert(*i);
}
Path storePath = readOnlyMode
? computeStorePathForText(name, contents)
: store->addTextToStore(name, contents, refs);
/* 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]. */
return makeStr(storePath, singleton<PathSet>(storePath));
}
/* Boolean constructors. */
static Expr primTrue(EvalState & state, const ATermVector & args)
{
return eTrue;
}
static Expr primFalse(EvalState & state, const ATermVector & args)
{
return eFalse;
}
/* Return the null value. */
static Expr primNull(EvalState & state, const ATermVector & args)
{
return makeNull();
}
/* Determine whether the argument is the null value. */
static Expr primIsNull(EvalState & state, const ATermVector & args)
{
return makeBool(matchNull(evalExpr(state, args[0])));
}
/* Determine whether the argument is a list. */
static Expr primIsList(EvalState & state, const ATermVector & args)
{
ATermList list;
return makeBool(matchList(evalExpr(state, args[0]), list));
}
static Path findDependency(Path dir, string dep)
{
if (dep[0] == '/') throw EvalError(
format("illegal absolute dependency `%1%'") % dep);
Path p = canonPath(dir + "/" + dep);
if (pathExists(p))
return p;
else
return "";
}
/* Make path `p' relative to directory `pivot'. E.g.,
relativise("/a/b/c", "a/b/x/y") => "../x/y". Both input paths
should be in absolute canonical form. */
static string relativise(Path pivot, Path p)
{
assert(pivot.size() > 0 && pivot[0] == '/');
assert(p.size() > 0 && p[0] == '/');
if (pivot == p) return ".";
/* `p' is in `pivot'? */
Path pivot2 = pivot + "/";
if (p.substr(0, pivot2.size()) == pivot2) {
return p.substr(pivot2.size());
}
/* Otherwise, `p' is in a parent of `pivot'. Find up till which
path component `p' and `pivot' match, and add an appropriate
number of `..' components. */
string::size_type i = 1;
while (1) {
string::size_type j = pivot.find('/', i);
if (j == string::npos) break;
j++;
if (pivot.substr(0, j) != p.substr(0, j)) break;
i = j;
}
string prefix;
unsigned int slashes = count(pivot.begin() + i, pivot.end(), '/') + 1;
while (slashes--) {
prefix += "../";
}
return prefix + p.substr(i);
}
static Expr primDependencyClosure(EvalState & state, const ATermVector & args)
{
startNest(nest, lvlDebug, "finding dependencies");
Expr attrs = evalExpr(state, args[0]);
/* Get the start set. */
Expr startSet = queryAttr(attrs, "startSet");
if (!startSet) throw EvalError("attribute `startSet' required");
ATermList startSet2 = evalList(state, startSet);
Path pivot;
PathSet workSet;
for (ATermIterator i(startSet2); i; ++i) {
PathSet context; /* !!! what to do? */
Path p = coerceToPath(state, *i, context);
workSet.insert(p);
pivot = dirOf(p);
}
/* Get the search path. */
PathSet searchPath;
Expr e = queryAttr(attrs, "searchPath");
if (e) {
ATermList list = evalList(state, e);
for (ATermIterator i(list); i; ++i) {
PathSet context; /* !!! what to do? */
Path p = coerceToPath(state, *i, context);
searchPath.insert(p);
}
}
Expr scanner = queryAttr(attrs, "scanner");
if (!scanner) throw EvalError("attribute `scanner' required");
/* Construct the dependency closure by querying the dependency of
each path in `workSet', adding the dependencies to
`workSet'. */
PathSet doneSet;
while (!workSet.empty()) {
Path path = *(workSet.begin());
workSet.erase(path);
if (doneSet.find(path) != doneSet.end()) continue;
doneSet.insert(path);
try {
/* Call the `scanner' function with `path' as argument. */
debug(format("finding dependencies in `%1%'") % path);
ATermList deps = evalList(state, makeCall(scanner, makeStr(path)));
/* Try to find the dependencies relative to the `path'. */
for (ATermIterator i(deps); i; ++i) {
string s = evalStringNoCtx(state, *i);
Path dep = findDependency(dirOf(path), s);
if (dep == "") {
for (PathSet::iterator j = searchPath.begin();
j != searchPath.end(); ++j)
{
dep = findDependency(*j, s);
if (dep != "") break;
}
}
if (dep == "")
debug(format("did NOT find dependency `%1%'") % s);
else {
debug(format("found dependency `%1%'") % dep);
workSet.insert(dep);
}
}
} catch (Error & e) {
e.addPrefix(format("while finding dependencies in `%1%':\n")
% path);
throw;
}
}
/* Return a list of the dependencies we've just found. */
ATermList deps = ATempty;
for (PathSet::iterator i = doneSet.begin(); i != doneSet.end(); ++i) {
deps = ATinsert(deps, makeStr(relativise(pivot, *i)));
deps = ATinsert(deps, makeStr(*i));
}
debug(format("dependency list is `%1%'") % makeList(deps));
return makeList(deps);
}
static Expr primAbort(EvalState & state, const ATermVector & args)
{
PathSet context;
throw Abort(format("evaluation aborted with the following error message: `%1%'") %
evalString(state, args[0], context));
}
/* Return the first element of a list. */
static Expr primHead(EvalState & state, const ATermVector & args)
{
ATermList list = evalList(state, args[0]);
if (ATisEmpty(list))
throw Error("`head' called on an empty list");
return evalExpr(state, ATgetFirst(list));
}
/* Return a list consisting of everything but the the first element of
a list. */
static Expr primTail(EvalState & state, const ATermVector & args)
{
ATermList list = evalList(state, args[0]);
if (ATisEmpty(list))
throw Error("`tail' called on an empty list");
return makeList(ATgetNext(list));
}
/* Return an environment variable. Use with care. */
static Expr primGetEnv(EvalState & state, const ATermVector & args)
{
string name = evalStringNoCtx(state, args[0]);
return makeStr(getEnv(name));
}
/* Return the names of the attributes in an attribute set as a sorted
list of strings. */
static Expr primAttrNames(EvalState & state, const ATermVector & args)
{
ATermMap attrs;
queryAllAttrs(evalExpr(state, args[0]), attrs);
StringSet names;
for (ATermMap::const_iterator i = attrs.begin(); i != attrs.end(); ++i)
names.insert(aterm2String(i->key));
ATermList list = ATempty;
for (StringSet::const_reverse_iterator i = names.rbegin();
i != names.rend(); ++i)
list = ATinsert(list, makeStr(*i, PathSet()));
return makeList(list);
}
/* Apply a function to every element of a list. */
static Expr primMap(EvalState & state, const ATermVector & args)
{
Expr fun = evalExpr(state, args[0]);
ATermList list = evalList(state, args[1]);
ATermList res = ATempty;
for (ATermIterator i(list); i; ++i)
res = ATinsert(res, makeCall(fun, *i));
return makeList(ATreverse(res));
}
/* Return a string constant representing the current platform. Note!
that differs between platforms, so Nix expressions using
`__currentSystem' can evaluate to different values on different
platforms. */
static Expr primCurrentSystem(EvalState & state, const ATermVector & args)
{
return makeStr(thisSystem);
}
static Expr primCurrentTime(EvalState & state, const ATermVector & args)
{
return ATmake("Int(<int>)", time(0));
}
/* Dynamic version of the `.' operator. */
static Expr primGetAttr(EvalState & state, const ATermVector & args)
{
string attr = evalStringNoCtx(state, args[0]);
return evalExpr(state, makeSelect(args[1], toATerm(attr)));
}
/* Dynamic version of the `?' operator. */
static Expr primHasAttr(EvalState & state, const ATermVector & args)
{
string attr = evalStringNoCtx(state, args[0]);
return evalExpr(state, makeOpHasAttr(args[1], toATerm(attr)));
}
static Expr primRemoveAttrs(EvalState & state, const ATermVector & args)
{
ATermMap attrs;
queryAllAttrs(evalExpr(state, args[0]), attrs, true);
ATermList list = evalList(state, args[1]);
for (ATermIterator i(list); i; ++i)
/* It's not an error for *i not to exist. */
attrs.remove(toATerm(evalStringNoCtx(state, *i)));
return makeAttrs(attrs);
}
static Expr primRelativise(EvalState & state, const ATermVector & args)
{
PathSet context; /* !!! what to do? */
Path pivot = coerceToPath(state, args[0], context);
Path path = coerceToPath(state, args[1], context);
return makeStr(relativise(pivot, path));
}
static Expr primAdd(EvalState & state, const ATermVector & args)
{
int i1 = evalInt(state, args[0]);
int i2 = evalInt(state, args[1]);
return makeInt(i1 + i2);
}
static Expr primLessThan(EvalState & state, const ATermVector & args)
{
int i1 = evalInt(state, args[0]);
int i2 = evalInt(state, args[1]);
return makeBool(i1 < i2);
}
struct FilterFromExpr : PathFilter
{
EvalState & state;
Expr filter;
FilterFromExpr(EvalState & state, Expr 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);
Expr call =
makeCall(
makeCall(filter, makePath(toATerm(path))),
makeStr(
S_ISREG(st.st_mode) ? "regular" :
S_ISDIR(st.st_mode) ? "directory" :
S_ISLNK(st.st_mode) ? "symlink" :
"unknown" /* not supported, will fail! */
));
return evalBool(state, call);
}
};
static Expr primFilterSource(EvalState & state, const ATermVector & args)
{
PathSet context;
Path path = coerceToPath(state, args[1], context);
if (!context.empty())
throw EvalError(format("string `%1%' cannot refer to other paths") % path);
FilterFromExpr filter(state, args[0]);
Path dstPath = readOnlyMode
? computeStorePathForPath(path, false, false, "", filter).first
: store->addToStore(path, false, false, "", filter);
return makeStr(dstPath, singleton<PathSet>(dstPath));
}
void EvalState::addPrimOps()
{
addPrimOp("builtins", 0, primBuiltins);
addPrimOp("true", 0, primTrue);
addPrimOp("false", 0, primFalse);
addPrimOp("null", 0, primNull);
addPrimOp("__currentSystem", 0, primCurrentSystem);
addPrimOp("__currentTime", 0, primCurrentTime);
addPrimOp("import", 1, primImport);
addPrimOp("__pathExists", 1, primPathExists);
addPrimOp("derivation!", 1, primDerivationStrict);
addPrimOp("derivation", 1, primDerivationLazy);
addPrimOp("baseNameOf", 1, primBaseNameOf);
addPrimOp("dirOf", 1, primDirOf);
addPrimOp("toString", 1, primToString);
addPrimOp("__toPath", 1, primToPath);
addPrimOp("__toXML", 1, primToXML);
addPrimOp("isNull", 1, primIsNull);
addPrimOp("__isList", 1, primIsList);
addPrimOp("dependencyClosure", 1, primDependencyClosure);
addPrimOp("abort", 1, primAbort);
addPrimOp("__head", 1, primHead);
addPrimOp("__tail", 1, primTail);
addPrimOp("__getEnv", 1, primGetEnv);
addPrimOp("__attrNames", 1, primAttrNames);
addPrimOp("map", 2, primMap);
addPrimOp("__getAttr", 2, primGetAttr);
addPrimOp("__hasAttr", 2, primHasAttr);
addPrimOp("removeAttrs", 2, primRemoveAttrs);
addPrimOp("relativise", 2, primRelativise);
addPrimOp("__add", 2, primAdd);
addPrimOp("__lessThan", 2, primLessThan);
addPrimOp("__toFile", 2, primToFile);
addPrimOp("__filterSource", 2, primFilterSource);
}
}