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/// @module system
/// Environment.
// @section environment
#include <lua.h>
#include <lauxlib.h>
#include "compat.h"
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include "windows.h"
#endif
/***
Gets the value of an environment variable.
__NOTE__: Windows has multiple copies of environment variables. For this reason,
the `setenv` function will not work with Lua's `os.getenv` on Windows. If you want
to use `setenv` then consider patching `os.getenv` with this implementation of `getenv`.
@function getenv
@tparam string name name of the environment variable
@treturn string|nil value of the environment variable, or nil if the variable is not set
*/
static int lua_get_environment_variable(lua_State* L) {
const char* variableName = luaL_checkstring(L, 1);
#ifdef _WIN32
// On Windows, use GetEnvironmentVariable to retrieve the value
DWORD bufferSize = GetEnvironmentVariable(variableName, NULL, 0);
if (bufferSize > 0) {
char* buffer = (char*)malloc(bufferSize);
if (GetEnvironmentVariable(variableName, buffer, bufferSize) > 0) {
lua_pushstring(L, buffer);
free(buffer);
return 1;
}
free(buffer);
}
#else
// On non-Windows platforms, use getenv to retrieve the value
const char* variableValue = getenv(variableName);
if (variableValue != NULL) {
lua_pushstring(L, variableValue);
return 1;
}
#endif
// If the variable is not set or an error occurs, push nil
lua_pushnil(L);
return 1;
}
/***
Returns a table with all environment variables.
@function getenvs
@treturn table table with all environment variables and their values
*/
static int lua_list_environment_variables(lua_State* L) {
lua_newtable(L);
#ifdef _WIN32
char* envStrings = GetEnvironmentStrings();
char* envString = envStrings;
if (envStrings == NULL) {
lua_pushnil(L);
return 1;
}
while (*envString != '\0') {
const char* envVar = envString;
// Split the environment variable into key and value
char* equals = strchr(envVar, '=');
if (equals != NULL) {
lua_pushlstring(L, envVar, equals - envVar); // Push the key
lua_pushstring(L, equals + 1); // Push the value
lua_settable(L, -3); // Set the key-value pair in the table
}
envString += strlen(envString) + 1;
}
FreeEnvironmentStrings(envStrings);
#else
extern char** environ;
if (environ != NULL) {
for (char** envVar = environ; *envVar != NULL; envVar++) {
const char* envVarStr = *envVar;
// Split the environment variable into key and value
char* equals = strchr(envVarStr, '=');
if (equals != NULL) {
lua_pushlstring(L, envVarStr, equals - envVarStr); // Push the key
lua_pushstring(L, equals + 1); // Push the value
lua_settable(L, -3); // Set the key-value pair in the table
}
}
}
#endif
return 1;
}
/***
Sets an environment variable.
__NOTE__: Windows has multiple copies of environment variables. For this reason, the
`setenv` function will not work with Lua's `os.getenv` on Windows. If you want to use
it then consider patching `os.getenv` with the implementation of `system.getenv`.
@function setenv
@tparam string name name of the environment variable
@tparam[opt] string value value of the environment variable, if `nil` the variable will be deleted (on
Windows, setting an empty string, will also delete the variable)
@treturn boolean success
*/
static int lua_set_environment_variable(lua_State* L) {
const char* variableName = luaL_checkstring(L, 1);
const char* variableValue = luaL_optstring(L, 2, NULL);
#ifdef _WIN32
// if (variableValue == NULL) {
// // If the value is nil, delete the environment variable
// if (SetEnvironmentVariable(variableName, NULL)) {
// lua_pushboolean(L, 1);
// } else {
// lua_pushboolean(L, 0);
// }
// } else {
// Set the environment variable with the provided value
if (SetEnvironmentVariable(variableName, variableValue)) {
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
// }
#else
if (variableValue == NULL) {
// If the value is nil, delete the environment variable
if (unsetenv(variableName) == 0) {
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
} else {
// Set the environment variable with the provided value
if (setenv(variableName, variableValue, 1) == 0) {
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
}
#endif
return 1;
}
static luaL_Reg func[] = {
{ "getenv", lua_get_environment_variable },
{ "setenv", lua_set_environment_variable },
{ "getenvs", lua_list_environment_variables },
{ NULL, NULL }
};
/*-------------------------------------------------------------------------
* Initializes module
*-------------------------------------------------------------------------*/
void environment_open(lua_State *L) {
luaL_setfuncs(L, func, 0);
}
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