edify/expr.cpp - android_bootable_recovery - Gitiles

 /*
  * Copyright (C) 2009 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "expr.h"

 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include <memory>
 #include <string>
 #include <unordered_map>
 #include <vector>

 #include <android-base/parseint.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>

 // Functions should:
 //
 //    - return a malloc()'d string
 //    - if Evaluate() on any argument returns nullptr, return nullptr.

 static bool BooleanString(const std::string& s) {
     return !s.empty();
 }

 bool Evaluate(State* state, Expr* expr, std::string* result) {
     if (result == nullptr) {
         return false;
     }

     std::unique_ptr<Value> v(expr->fn(expr->name, state, expr->argc, expr->argv));
     if (!v) {
         return false;
     }
     if (v->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "expecting string, got value type %d", v->type);
         return false;
     }

     *result = v->data;
     return true;
 }

 Value* EvaluateValue(State* state, Expr* expr) {
     return expr->fn(expr->name, state, expr->argc, expr->argv);
 }

 Value* StringValue(const char* str) {
     if (str == nullptr) {
         return nullptr;
     }
     return new Value(VAL_STRING, str);
 }

 Value* StringValue(const std::string& str) {
     return StringValue(str.c_str());
 }

 Value* ConcatFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (argc == 0) {
         return StringValue("");
     }
     std::string result;
     for (int i = 0; i < argc; ++i) {
         std::string str;
         if (!Evaluate(state, argv[i], &str)) {
             return nullptr;
         }
         result += str;
     }

     return StringValue(result);
 }

 Value* IfElseFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (argc != 2 && argc != 3) {
         state->errmsg = "ifelse expects 2 or 3 arguments";
         return nullptr;
     }

     std::string cond;
     if (!Evaluate(state, argv[0], &cond)) {
         return nullptr;
     }

     if (!cond.empty()) {
         return EvaluateValue(state, argv[1]);
     } else if (argc == 3) {
         return EvaluateValue(state, argv[2]);
     }

     return StringValue("");
 }

 Value* AbortFn(const char* name, State* state, int argc, Expr* argv[]) {
     std::string msg;
     if (argc > 0 && Evaluate(state, argv[0], &msg)) {
         state->errmsg = msg;
     } else {
         state->errmsg = "called abort()";
     }
     return nullptr;
 }

 Value* AssertFn(const char* name, State* state, int argc, Expr* argv[]) {
     for (int i = 0; i < argc; ++i) {
         std::string result;
         if (!Evaluate(state, argv[i], &result)) {
             return nullptr;
         }
         if (result.empty()) {
             int len = argv[i]->end - argv[i]->start;
             state->errmsg = "assert failed: " + state->script.substr(argv[i]->start, len);
             return nullptr;
         }
     }
     return StringValue("");
 }

 Value* SleepFn(const char* name, State* state, int argc, Expr* argv[]) {
     std::string val;
     if (!Evaluate(state, argv[0], &val)) {
         return nullptr;
     }

     int v;
     if (!android::base::ParseInt(val.c_str(), &v, 0)) {
         return nullptr;
     }
     sleep(v);

     return StringValue(val);
 }

 Value* StdoutFn(const char* name, State* state, int argc, Expr* argv[]) {
     for (int i = 0; i < argc; ++i) {
         std::string v;
         if (!Evaluate(state, argv[i], &v)) {
             return nullptr;
         }
         fputs(v.c_str(), stdout);
     }
     return StringValue("");
 }

 Value* LogicalAndFn(const char* name, State* state,
                    int argc, Expr* argv[]) {
     std::string left;
     if (!Evaluate(state, argv[0], &left)) {
         return nullptr;
     }
     if (BooleanString(left)) {
         return EvaluateValue(state, argv[1]);
     } else {
         return StringValue("");
     }
 }

 Value* LogicalOrFn(const char* name, State* state,
                    int argc, Expr* argv[]) {
     std::string left;
     if (!Evaluate(state, argv[0], &left)) {
         return nullptr;
     }
     if (!BooleanString(left)) {
         return EvaluateValue(state, argv[1]);
     } else {
         return StringValue(left);
     }
 }

 Value* LogicalNotFn(const char* name, State* state,
                     int argc, Expr* argv[]) {
     std::string val;
     if (!Evaluate(state, argv[0], &val)) {
         return nullptr;
     }

     return StringValue(BooleanString(val) ? "" : "t");
 }

 Value* SubstringFn(const char* name, State* state,
                    int argc, Expr* argv[]) {
     std::string needle;
     if (!Evaluate(state, argv[0], &needle)) {
         return nullptr;
     }

     std::string haystack;
     if (!Evaluate(state, argv[1], &haystack)) {
         return nullptr;
     }

     std::string result = (haystack.find(needle) != std::string::npos) ? "t" : "";
     return StringValue(result);
 }

 Value* EqualityFn(const char* name, State* state, int argc, Expr* argv[]) {
     std::string left;
     if (!Evaluate(state, argv[0], &left)) {
         return nullptr;
     }
     std::string right;
     if (!Evaluate(state, argv[1], &right)) {
         return nullptr;
     }

     const char* result = (left == right) ? "t" : "";
     return StringValue(result);
 }

 Value* InequalityFn(const char* name, State* state, int argc, Expr* argv[]) {
     std::string left;
     if (!Evaluate(state, argv[0], &left)) {
         return nullptr;
     }
     std::string right;
     if (!Evaluate(state, argv[1], &right)) {
         return nullptr;
     }

     const char* result = (left != right) ? "t" : "";
     return StringValue(result);
 }

 Value* SequenceFn(const char* name, State* state, int argc, Expr* argv[]) {
     std::unique_ptr<Value> left(EvaluateValue(state, argv[0]));
     if (!left) {
         return nullptr;
     }
     return EvaluateValue(state, argv[1]);
 }

 Value* LessThanIntFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (argc != 2) {
         state->errmsg = "less_than_int expects 2 arguments";
         return nullptr;
     }

     char* left;
     char* right;
     if (ReadArgs(state, argv, 2, &left, &right) < 0) return nullptr;

     bool result = false;
     char* end;

     // Parse up to at least long long or 64-bit integers.
     int64_t l_int = static_cast<int64_t>(strtoll(left, &end, 10));
     if (left[0] == '\0' || *end != '\0') {
         goto done;
     }

     int64_t r_int;
     r_int = static_cast<int64_t>(strtoll(right, &end, 10));
     if (right[0] == '\0' || *end != '\0') {
         goto done;
     }

     result = l_int < r_int;

   done:
     free(left);
     free(right);
     return StringValue(result ? "t" : "");
 }

 Value* GreaterThanIntFn(const char* name, State* state,
                         int argc, Expr* argv[]) {
     if (argc != 2) {
         state->errmsg = "greater_than_int expects 2 arguments";
         return nullptr;
     }

     Expr* temp[2];
     temp[0] = argv[1];
     temp[1] = argv[0];

     return LessThanIntFn(name, state, 2, temp);
 }

 Value* Literal(const char* name, State* state, int argc, Expr* argv[]) {
     return StringValue(name);
 }

 // -----------------------------------------------------------------
 //   the function table
 // -----------------------------------------------------------------

 static std::unordered_map<std::string, Function> fn_table;

 void RegisterFunction(const std::string& name, Function fn) {
     fn_table[name] = fn;
 }

 Function FindFunction(const std::string& name) {
     if (fn_table.find(name) == fn_table.end()) {
         return nullptr;
     } else {
         return fn_table[name];
     }
 }

 void RegisterBuiltins() {
     RegisterFunction("ifelse", IfElseFn);
     RegisterFunction("abort", AbortFn);
     RegisterFunction("assert", AssertFn);
     RegisterFunction("concat", ConcatFn);
     RegisterFunction("is_substring", SubstringFn);
     RegisterFunction("stdout", StdoutFn);
     RegisterFunction("sleep", SleepFn);

     RegisterFunction("less_than_int", LessThanIntFn);
     RegisterFunction("greater_than_int", GreaterThanIntFn);
 }


 // -----------------------------------------------------------------
 //   convenience methods for functions
 // -----------------------------------------------------------------

 // Evaluate the expressions in argv, and put the results of strings in
 // args. If any expression evaluates to nullptr, free the rest and return
 // false. Return true on success.
 bool ReadArgs(State* state, int argc, Expr* argv[], std::vector<std::string>* args) {
     if (args == nullptr) {
         return false;
     }
     for (int i = 0; i < argc; ++i) {
         std::string var;
         if (!Evaluate(state, argv[i], &var)) {
             args->clear();
             return false;
         }
         args->push_back(var);
     }
     return true;
 }

 // Evaluate the expressions in argv, and put the results of Value* in
 // args. If any expression evaluate to nullptr, free the rest and return
 // false. Return true on success.
 bool ReadValueArgs(State* state, int argc, Expr* argv[],
                    std::vector<std::unique_ptr<Value>>* args) {
     if (args == nullptr) {
         return false;
     }
     for (int i = 0; i < argc; ++i) {
         std::unique_ptr<Value> v(EvaluateValue(state, argv[i]));
         if (!v) {
             args->clear();
             return false;
         }
         args->push_back(std::move(v));
     }
     return true;
 }

 // Evaluate the expressions in argv, giving 'count' char* (the ... is
 // zero or more char** to put them in).  If any expression evaluates
 // to NULL, free the rest and return -1.  Return 0 on success.
 int ReadArgs(State* state, Expr* argv[], int count, ...) {
     char** args = reinterpret_cast<char**>(malloc(count * sizeof(char*)));
     va_list v;
     va_start(v, count);
     int i;
     for (i = 0; i < count; ++i) {
         std::string str;
         if (!Evaluate(state, argv[i], &str) ||
                 (args[i] = strdup(str.c_str())) == nullptr) {
             va_end(v);
             int j;
             for (j = 0; j < i; ++j) {
                 free(args[j]);
             }
             free(args);
             return -1;
         }
         *(va_arg(v, char**)) = args[i];
     }
     va_end(v);
     free(args);
     return 0;
 }

 // Evaluate the expressions in argv, giving 'count' Value* (the ... is
 // zero or more Value** to put them in).  If any expression evaluates
 // to NULL, free the rest and return -1.  Return 0 on success.
 int ReadValueArgs(State* state, Expr* argv[], int count, ...) {
     Value** args = new Value*[count];
     va_list v;
     va_start(v, count);
     for (int i = 0; i < count; ++i) {
         args[i] = EvaluateValue(state, argv[i]);
         if (args[i] == NULL) {
             va_end(v);
             int j;
             for (j = 0; j < i; ++j) {
                 delete args[j];
             }
             delete[] args;
             return -1;
         }
         *(va_arg(v, Value**)) = args[i];
     }
     va_end(v);
     delete[] args;
     return 0;
 }

 // Evaluate the expressions in argv, returning an array of char*
 // results.  If any evaluate to NULL, free the rest and return NULL.
 // The caller is responsible for freeing the returned array and the
 // strings it contains.
 char** ReadVarArgs(State* state, int argc, Expr* argv[]) {
     char** args = (char**)malloc(argc * sizeof(char*));
     for (int i = 0; i < argc; ++i) {
         std::string str;
         if (!Evaluate(state, argv[i], &str) ||
                 (args[i] = strdup(str.c_str())) == nullptr) {
             for (int j = 0; j < i; ++j) {
                 free(args[j]);
             }
             free(args);
             return NULL;
         }
     }
     return args;
 }

 // Evaluate the expressions in argv, returning an array of Value*
 // results.  If any evaluate to NULL, free the rest and return NULL.
 // The caller is responsible for freeing the returned array and the
 // Values it contains.
 Value** ReadValueVarArgs(State* state, int argc, Expr* argv[]) {
     Value** args = new Value*[argc];
     int i = 0;
     for (i = 0; i < argc; ++i) {
         args[i] = EvaluateValue(state, argv[i]);
         if (args[i] == NULL) {
             int j;
             for (j = 0; j < i; ++j) {
                 delete args[j];
             }
             delete[] args;
             return NULL;
         }
     }
     return args;
 }

 // Use printf-style arguments to compose an error message to put into
 // *state.  Returns nullptr.
 Value* ErrorAbort(State* state, const char* format, ...) {
     va_list ap;
     va_start(ap, format);
     android::base::StringAppendV(&state->errmsg, format, ap);
     va_end(ap);
     return nullptr;
 }

 Value* ErrorAbort(State* state, CauseCode cause_code, const char* format, ...) {
     va_list ap;
     va_start(ap, format);
     android::base::StringAppendV(&state->errmsg, format, ap);
     va_end(ap);
     state->cause_code = cause_code;
     return nullptr;
 }

 State::State(const std::string& script, void* cookie) :
     script(script),
     cookie(cookie) {
 }
	/*
	* Copyright (C) 2009 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "expr.h"

	#include <stdarg.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include <memory>
	#include <string>
	#include <unordered_map>
	#include <vector>

	#include <android-base/parseint.h>
	#include <android-base/stringprintf.h>
	#include <android-base/strings.h>

	// Functions should:
	//
	// - return a malloc()'d string
	// - if Evaluate() on any argument returns nullptr, return nullptr.

	static bool BooleanString(const std::string& s) {
	return !s.empty();
	}

	bool Evaluate(State* state, Expr* expr, std::string* result) {
	if (result == nullptr) {
	return false;
	}

	std::unique_ptr<Value> v(expr->fn(expr->name, state, expr->argc, expr->argv));
	if (!v) {
	return false;
	}
	if (v->type != VAL_STRING) {
	ErrorAbort(state, kArgsParsingFailure, "expecting string, got value type %d", v->type);
	return false;
	}

	*result = v->data;
	return true;
	}

	Value* EvaluateValue(State* state, Expr* expr) {
	return expr->fn(expr->name, state, expr->argc, expr->argv);
	}

	Value* StringValue(const char* str) {
	if (str == nullptr) {
	return nullptr;
	}
	return new Value(VAL_STRING, str);
	}

	Value* StringValue(const std::string& str) {
	return StringValue(str.c_str());
	}

	Value* ConcatFn(const char* name, State* state, int argc, Expr* argv[]) {
	if (argc == 0) {
	return StringValue("");
	}
	std::string result;
	for (int i = 0; i < argc; ++i) {
	std::string str;
	if (!Evaluate(state, argv[i], &str)) {
	return nullptr;
	}
	result += str;
	}

	return StringValue(result);
	}

	Value* IfElseFn(const char* name, State* state, int argc, Expr* argv[]) {
	if (argc != 2 && argc != 3) {
	state->errmsg = "ifelse expects 2 or 3 arguments";
	return nullptr;
	}

	std::string cond;
	if (!Evaluate(state, argv[0], &cond)) {
	return nullptr;
	}

	if (!cond.empty()) {
	return EvaluateValue(state, argv[1]);
	} else if (argc == 3) {
	return EvaluateValue(state, argv[2]);
	}

	return StringValue("");
	}

	Value* AbortFn(const char* name, State* state, int argc, Expr* argv[]) {
	std::string msg;
	if (argc > 0 && Evaluate(state, argv[0], &msg)) {
	state->errmsg = msg;
	} else {
	state->errmsg = "called abort()";
	}
	return nullptr;
	}

	Value* AssertFn(const char* name, State* state, int argc, Expr* argv[]) {
	for (int i = 0; i < argc; ++i) {
	std::string result;
	if (!Evaluate(state, argv[i], &result)) {
	return nullptr;
	}
	if (result.empty()) {
	int len = argv[i]->end - argv[i]->start;
	state->errmsg = "assert failed: " + state->script.substr(argv[i]->start, len);
	return nullptr;
	}
	}
	return StringValue("");
	}

	Value* SleepFn(const char* name, State* state, int argc, Expr* argv[]) {
	std::string val;
	if (!Evaluate(state, argv[0], &val)) {
	return nullptr;
	}

	int v;
	if (!android::base::ParseInt(val.c_str(), &v, 0)) {
	return nullptr;
	}
	sleep(v);

	return StringValue(val);
	}

	Value* StdoutFn(const char* name, State* state, int argc, Expr* argv[]) {
	for (int i = 0; i < argc; ++i) {
	std::string v;
	if (!Evaluate(state, argv[i], &v)) {
	return nullptr;
	}
	fputs(v.c_str(), stdout);
	}
	return StringValue("");
	}

	Value* LogicalAndFn(const char* name, State* state,
	int argc, Expr* argv[]) {
	std::string left;
	if (!Evaluate(state, argv[0], &left)) {
	return nullptr;
	}
	if (BooleanString(left)) {
	return EvaluateValue(state, argv[1]);
	} else {
	return StringValue("");
	}
	}

	Value* LogicalOrFn(const char* name, State* state,
	int argc, Expr* argv[]) {
	std::string left;
	if (!Evaluate(state, argv[0], &left)) {
	return nullptr;
	}
	if (!BooleanString(left)) {
	return EvaluateValue(state, argv[1]);
	} else {
	return StringValue(left);
	}
	}

	Value* LogicalNotFn(const char* name, State* state,
	int argc, Expr* argv[]) {
	std::string val;
	if (!Evaluate(state, argv[0], &val)) {
	return nullptr;
	}

	return StringValue(BooleanString(val) ? "" : "t");
	}

	Value* SubstringFn(const char* name, State* state,
	int argc, Expr* argv[]) {
	std::string needle;
	if (!Evaluate(state, argv[0], &needle)) {
	return nullptr;
	}

	std::string haystack;
	if (!Evaluate(state, argv[1], &haystack)) {
	return nullptr;
	}

	std::string result = (haystack.find(needle) != std::string::npos) ? "t" : "";
	return StringValue(result);
	}

	Value* EqualityFn(const char* name, State* state, int argc, Expr* argv[]) {
	std::string left;
	if (!Evaluate(state, argv[0], &left)) {
	return nullptr;
	}
	std::string right;
	if (!Evaluate(state, argv[1], &right)) {
	return nullptr;
	}

	const char* result = (left == right) ? "t" : "";
	return StringValue(result);
	}

	Value* InequalityFn(const char* name, State* state, int argc, Expr* argv[]) {
	std::string left;
	if (!Evaluate(state, argv[0], &left)) {
	return nullptr;
	}
	std::string right;
	if (!Evaluate(state, argv[1], &right)) {
	return nullptr;
	}

	const char* result = (left != right) ? "t" : "";
	return StringValue(result);
	}

	Value* SequenceFn(const char* name, State* state, int argc, Expr* argv[]) {
	std::unique_ptr<Value> left(EvaluateValue(state, argv[0]));
	if (!left) {
	return nullptr;
	}
	return EvaluateValue(state, argv[1]);
	}

	Value* LessThanIntFn(const char* name, State* state, int argc, Expr* argv[]) {
	if (argc != 2) {
	state->errmsg = "less_than_int expects 2 arguments";
	return nullptr;
	}

	char* left;
	char* right;
	if (ReadArgs(state, argv, 2, &left, &right) < 0) return nullptr;

	bool result = false;
	char* end;

	// Parse up to at least long long or 64-bit integers.
	int64_t l_int = static_cast<int64_t>(strtoll(left, &end, 10));
	if (left[0] == '\0' \|\| *end != '\0') {
	goto done;
	}

	int64_t r_int;
	r_int = static_cast<int64_t>(strtoll(right, &end, 10));
	if (right[0] == '\0' \|\| *end != '\0') {
	goto done;
	}

	result = l_int < r_int;

	done:
	free(left);
	free(right);
	return StringValue(result ? "t" : "");
	}

	Value* GreaterThanIntFn(const char* name, State* state,
	int argc, Expr* argv[]) {
	if (argc != 2) {
	state->errmsg = "greater_than_int expects 2 arguments";
	return nullptr;
	}

	Expr* temp[2];
	temp[0] = argv[1];
	temp[1] = argv[0];

	return LessThanIntFn(name, state, 2, temp);
	}

	Value* Literal(const char* name, State* state, int argc, Expr* argv[]) {
	return StringValue(name);
	}

	// -----------------------------------------------------------------
	// the function table
	// -----------------------------------------------------------------

	static std::unordered_map<std::string, Function> fn_table;

	void RegisterFunction(const std::string& name, Function fn) {
	fn_table[name] = fn;
	}

	Function FindFunction(const std::string& name) {
	if (fn_table.find(name) == fn_table.end()) {
	return nullptr;
	} else {
	return fn_table[name];
	}
	}

	void RegisterBuiltins() {
	RegisterFunction("ifelse", IfElseFn);
	RegisterFunction("abort", AbortFn);
	RegisterFunction("assert", AssertFn);
	RegisterFunction("concat", ConcatFn);
	RegisterFunction("is_substring", SubstringFn);
	RegisterFunction("stdout", StdoutFn);
	RegisterFunction("sleep", SleepFn);

	RegisterFunction("less_than_int", LessThanIntFn);
	RegisterFunction("greater_than_int", GreaterThanIntFn);
	}


	// -----------------------------------------------------------------
	// convenience methods for functions
	// -----------------------------------------------------------------

	// Evaluate the expressions in argv, and put the results of strings in
	// args. If any expression evaluates to nullptr, free the rest and return
	// false. Return true on success.
	bool ReadArgs(State* state, int argc, Expr* argv[], std::vector<std::string>* args) {
	if (args == nullptr) {
	return false;
	}
	for (int i = 0; i < argc; ++i) {
	std::string var;
	if (!Evaluate(state, argv[i], &var)) {
	args->clear();
	return false;
	}
	args->push_back(var);
	}
	return true;
	}

	// Evaluate the expressions in argv, and put the results of Value* in
	// args. If any expression evaluate to nullptr, free the rest and return
	// false. Return true on success.
	bool ReadValueArgs(State* state, int argc, Expr* argv[],
	std::vector<std::unique_ptr<Value>>* args) {
	if (args == nullptr) {
	return false;
	}
	for (int i = 0; i < argc; ++i) {
	std::unique_ptr<Value> v(EvaluateValue(state, argv[i]));
	if (!v) {
	args->clear();
	return false;
	}
	args->push_back(std::move(v));
	}
	return true;
	}

	// Evaluate the expressions in argv, giving 'count' char* (the ... is
	// zero or more char** to put them in). If any expression evaluates
	// to NULL, free the rest and return -1. Return 0 on success.
	int ReadArgs(State* state, Expr* argv[], int count, ...) {
	char args = reinterpret_cast<char>(malloc(count * sizeof(char*)));
	va_list v;
	va_start(v, count);
	int i;
	for (i = 0; i < count; ++i) {
	std::string str;
	if (!Evaluate(state, argv[i], &str) \|\|
	(args[i] = strdup(str.c_str())) == nullptr) {
	va_end(v);
	int j;
	for (j = 0; j < i; ++j) {
	free(args[j]);
	}
	free(args);
	return -1;
	}
	(va_arg(v, char*)) = args[i];
	}
	va_end(v);
	free(args);
	return 0;
	}

	// Evaluate the expressions in argv, giving 'count' Value* (the ... is
	// zero or more Value** to put them in). If any expression evaluates
	// to NULL, free the rest and return -1. Return 0 on success.
	int ReadValueArgs(State* state, Expr* argv[], int count, ...) {
	Value** args = new Value*[count];
	va_list v;
	va_start(v, count);
	for (int i = 0; i < count; ++i) {
	args[i] = EvaluateValue(state, argv[i]);
	if (args[i] == NULL) {
	va_end(v);
	int j;
	for (j = 0; j < i; ++j) {
	delete args[j];
	}
	delete[] args;
	return -1;
	}
	(va_arg(v, Value*)) = args[i];
	}
	va_end(v);
	delete[] args;
	return 0;
	}

	// Evaluate the expressions in argv, returning an array of char*
	// results. If any evaluate to NULL, free the rest and return NULL.
	// The caller is responsible for freeing the returned array and the
	// strings it contains.
	char** ReadVarArgs(State* state, int argc, Expr* argv[]) {
	char args = (char)malloc(argc * sizeof(char*));
	for (int i = 0; i < argc; ++i) {
	std::string str;
	if (!Evaluate(state, argv[i], &str) \|\|
	(args[i] = strdup(str.c_str())) == nullptr) {
	for (int j = 0; j < i; ++j) {
	free(args[j]);
	}
	free(args);
	return NULL;
	}
	}
	return args;
	}

	// Evaluate the expressions in argv, returning an array of Value*
	// results. If any evaluate to NULL, free the rest and return NULL.
	// The caller is responsible for freeing the returned array and the
	// Values it contains.
	Value** ReadValueVarArgs(State* state, int argc, Expr* argv[]) {
	Value** args = new Value*[argc];
	int i = 0;
	for (i = 0; i < argc; ++i) {
	args[i] = EvaluateValue(state, argv[i]);
	if (args[i] == NULL) {
	int j;
	for (j = 0; j < i; ++j) {
	delete args[j];
	}
	delete[] args;
	return NULL;
	}
	}
	return args;
	}

	// Use printf-style arguments to compose an error message to put into
	// *state. Returns nullptr.
	Value* ErrorAbort(State* state, const char* format, ...) {
	va_list ap;
	va_start(ap, format);
	android::base::StringAppendV(&state->errmsg, format, ap);
	va_end(ap);
	return nullptr;
	}

	Value* ErrorAbort(State* state, CauseCode cause_code, const char* format, ...) {
	va_list ap;
	va_start(ap, format);
	android::base::StringAppendV(&state->errmsg, format, ap);
	va_end(ap);
	state->cause_code = cause_code;
	return nullptr;
	}

	State::State(const std::string& script, void* cookie) :
	script(script),
	cookie(cookie) {
	}