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Merge pull request #10555 from jlesquembre/jl/c-api_check-init
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Add isValid to nix::Value
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@roberth
roberth committed May 1, 2024
2 parents 5279e1f + 6acf02b commit e17aad2
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Showing 6 changed files with 204 additions and 60 deletions.
87 changes: 57 additions & 30 deletions src/libexpr-c/nix_api_value.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@
# include "gc_cpp.h"
#endif

// Helper function to throw an exception if value is null
// Internal helper functions to check [in] and [out] `Value *` parameters
static const nix::Value & check_value_not_null(const Value * value)
{
if (!value) {
Expand All @@ -37,6 +37,33 @@ static nix::Value & check_value_not_null(Value * value)
return *((nix::Value *) value);
}

static const nix::Value & check_value_in(const Value * value)
{
auto & v = check_value_not_null(value);
if (!v.isValid()) {
throw std::runtime_error("Uninitialized Value");
}
return v;
}

static nix::Value & check_value_in(Value * value)
{
auto & v = check_value_not_null(value);
if (!v.isValid()) {
throw std::runtime_error("Uninitialized Value");
}
return v;
}

static nix::Value & check_value_out(Value * value)
{
auto & v = check_value_not_null(value);
if (v.isValid()) {
throw std::runtime_error("Value already initialized. Variables are immutable");
}
return v;
}

/**
* Helper function to convert calls from nix into C API.
*
Expand Down Expand Up @@ -111,7 +138,7 @@ ValueType nix_get_type(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
using namespace nix;
switch (v.type()) {
case nThunk:
Expand Down Expand Up @@ -147,7 +174,7 @@ const char * nix_get_typename(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
auto s = nix::showType(v);
return strdup(s.c_str());
}
Expand All @@ -159,7 +186,7 @@ bool nix_get_bool(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nBool);
return v.boolean();
}
Expand All @@ -171,7 +198,7 @@ nix_err nix_get_string(nix_c_context * context, const Value * value, nix_get_str
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nString);
call_nix_get_string_callback(v.c_str(), callback, user_data);
}
Expand All @@ -183,7 +210,7 @@ const char * nix_get_path_string(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nPath);
// NOTE (from @yorickvP)
// v._path.path should work but may not be how Eelco intended it.
Expand All @@ -202,7 +229,7 @@ unsigned int nix_get_list_size(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nList);
return v.listSize();
}
Expand All @@ -214,7 +241,7 @@ unsigned int nix_get_attrs_size(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nAttrs);
return v.attrs()->size();
}
Expand All @@ -226,7 +253,7 @@ double nix_get_float(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nFloat);
return v.fpoint();
}
Expand All @@ -238,7 +265,7 @@ int64_t nix_get_int(nix_c_context * context, const Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nInt);
return v.integer();
}
Expand All @@ -250,7 +277,7 @@ ExternalValue * nix_get_external(nix_c_context * context, Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
assert(v.type() == nix::nExternal);
return (ExternalValue *) v.external();
}
Expand All @@ -262,7 +289,7 @@ Value * nix_get_list_byidx(nix_c_context * context, const Value * value, EvalSta
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nList);
auto * p = v.listElems()[ix];
nix_gc_incref(nullptr, p);
Expand All @@ -278,7 +305,7 @@ Value * nix_get_attr_byname(nix_c_context * context, const Value * value, EvalSt
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nAttrs);
nix::Symbol s = state->state.symbols.create(name);
auto attr = v.attrs()->get(s);
Expand All @@ -298,7 +325,7 @@ bool nix_has_attr_byname(nix_c_context * context, const Value * value, EvalState
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
assert(v.type() == nix::nAttrs);
nix::Symbol s = state->state.symbols.create(name);
auto attr = v.attrs()->get(s);
Expand All @@ -315,7 +342,7 @@ nix_get_attr_byidx(nix_c_context * context, const Value * value, EvalState * sta
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
const nix::Attr & a = (*v.attrs())[i];
*name = ((const std::string &) (state->state.symbols[a.name])).c_str();
nix_gc_incref(nullptr, a.value);
Expand All @@ -330,7 +357,7 @@ const char * nix_get_attr_name_byidx(nix_c_context * context, const Value * valu
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
const nix::Attr & a = (*v.attrs())[i];
return ((const std::string &) (state->state.symbols[a.name])).c_str();
}
Expand All @@ -342,7 +369,7 @@ nix_err nix_init_bool(nix_c_context * context, Value * value, bool b)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkBool(b);
}
NIXC_CATCH_ERRS
Expand All @@ -354,7 +381,7 @@ nix_err nix_init_string(nix_c_context * context, Value * value, const char * str
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkString(std::string_view(str));
}
NIXC_CATCH_ERRS
Expand All @@ -365,7 +392,7 @@ nix_err nix_init_path_string(nix_c_context * context, EvalState * s, Value * val
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkPath(s->state.rootPath(nix::CanonPath(str)));
}
NIXC_CATCH_ERRS
Expand All @@ -376,7 +403,7 @@ nix_err nix_init_float(nix_c_context * context, Value * value, double d)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkFloat(d);
}
NIXC_CATCH_ERRS
Expand All @@ -387,7 +414,7 @@ nix_err nix_init_int(nix_c_context * context, Value * value, int64_t i)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkInt(i);
}
NIXC_CATCH_ERRS
Expand All @@ -398,7 +425,7 @@ nix_err nix_init_null(nix_c_context * context, Value * value)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkNull();
}
NIXC_CATCH_ERRS
Expand All @@ -422,7 +449,7 @@ nix_err nix_init_external(nix_c_context * context, Value * value, ExternalValue
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
auto r = (nix::ExternalValueBase *) val;
v.mkExternal(r);
}
Expand Down Expand Up @@ -469,7 +496,7 @@ nix_err nix_make_list(nix_c_context * context, ListBuilder * list_builder, Value
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkList(list_builder->builder);
}
NIXC_CATCH_ERRS
Expand All @@ -480,19 +507,19 @@ nix_err nix_init_primop(nix_c_context * context, Value * value, PrimOp * p)
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkPrimOp((nix::PrimOp *) p);
}
NIXC_CATCH_ERRS
}

nix_err nix_copy_value(nix_c_context * context, Value * value, Value * source)
nix_err nix_copy_value(nix_c_context * context, Value * value, const Value * source)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & s = check_value_not_null(source);
auto & v = check_value_out(value);
auto & s = check_value_in(source);
v = s;
}
NIXC_CATCH_ERRS
Expand All @@ -503,7 +530,7 @@ nix_err nix_make_attrs(nix_c_context * context, Value * value, BindingsBuilder *
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_out(value);
v.mkAttrs(b->builder);
}
NIXC_CATCH_ERRS
Expand Down Expand Up @@ -550,7 +577,7 @@ nix_realised_string * nix_string_realise(nix_c_context * context, EvalState * st
if (context)
context->last_err_code = NIX_OK;
try {
auto & v = check_value_not_null(value);
auto & v = check_value_in(value);
nix::NixStringContext stringContext;
auto rawStr = state->state.coerceToString(nix::noPos, v, stringContext, "while realising a string").toOwned();
nix::StorePathSet storePaths;
Expand Down
2 changes: 1 addition & 1 deletion src/libexpr-c/nix_api_value.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -422,7 +422,7 @@ nix_err nix_init_primop(nix_c_context * context, Value * value, PrimOp * op);
* @param[in] source value to copy from
* @return error code, NIX_OK on success.
*/
nix_err nix_copy_value(nix_c_context * context, Value * value, Value * source);
nix_err nix_copy_value(nix_c_context * context, Value * value, const Value * source);
/**@}*/

/** @brief Create a bindings builder
Expand Down
14 changes: 13 additions & 1 deletion src/libexpr/value.hh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ class BindingsBuilder;


typedef enum {
tUninitialized = 0,
tInt = 1,
tBool,
tString,
Expand Down Expand Up @@ -166,7 +167,7 @@ public:
struct Value
{
private:
InternalType internalType;
InternalType internalType = tUninitialized;

friend std::string showType(const Value & v);

Expand Down Expand Up @@ -270,6 +271,7 @@ public:
inline ValueType type(bool invalidIsThunk = false) const
{
switch (internalType) {
case tUninitialized: break;
case tInt: return nInt;
case tBool: return nBool;
case tString: return nString;
Expand All @@ -294,6 +296,16 @@ public:
internalType = newType;
}

/**
* A value becomes valid when it is initialized. We don't use this
* in the evaluator; only in the bindings, where the slight extra
* cost is warranted because of inexperienced callers.
*/
inline bool isValid() const
{
return internalType != tUninitialized;
}

inline void mkInt(NixInt n)
{
finishValue(tInt, { .integer = n });
Expand Down

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