d9c9d10d9d
A few more changes to edify:
- fix write_raw_image(); my last change neglected to close the write
context, so the written image was corrupt.
- each expression tracks the span of the source code from which it
was compiled, so that assert()'s error message can include the
source of the expression that failed.
- the 'cookie' argument to each Function is replaced with a State
object, which contains the cookie, the source script (for use with
the above spans), and the current error message (replacing the
global variables that were used for this purpose).
- in the recovery image, a new command "ui_print" can be sent back
through the command pipe to cause text to appear on the screen.
Add a new ui_print() function to print things from scripts.
Rename existing "print" function to "stdout".
123 lines
4.2 KiB
C
123 lines
4.2 KiB
C
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _EXPRESSION_H
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#define _EXPRESSION_H
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#include "yydefs.h"
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#define MAX_STRING_LEN 1024
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typedef struct Expr Expr;
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typedef struct {
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// Optional pointer to app-specific data; the core of edify never
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// uses this value.
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void* cookie;
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// The source of the original script. Must be NULL-terminated,
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// and in writable memory (Evaluate may make temporary changes to
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// it but will restore it when done).
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char* script;
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// The error message (if any) returned if the evaluation aborts.
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// Should be NULL initially, will be either NULL or a malloc'd
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// pointer after Evaluate() returns.
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char* errmsg;
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} State;
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typedef char* (*Function)(const char* name, State* state,
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int argc, Expr* argv[]);
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struct Expr {
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Function fn;
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char* name;
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int argc;
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Expr** argv;
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int start, end;
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};
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char* Evaluate(State* state, Expr* expr);
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// Glue to make an Expr out of a literal.
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char* Literal(const char* name, State* state, int argc, Expr* argv[]);
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// Functions corresponding to various syntactic sugar operators.
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// ("concat" is also available as a builtin function, to concatenate
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// more than two strings.)
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char* ConcatFn(const char* name, State* state, int argc, Expr* argv[]);
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char* LogicalAndFn(const char* name, State* state, int argc, Expr* argv[]);
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char* LogicalOrFn(const char* name, State* state, int argc, Expr* argv[]);
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char* LogicalNotFn(const char* name, State* state, int argc, Expr* argv[]);
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char* SubstringFn(const char* name, State* state, int argc, Expr* argv[]);
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char* EqualityFn(const char* name, State* state, int argc, Expr* argv[]);
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char* InequalityFn(const char* name, State* state, int argc, Expr* argv[]);
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char* SequenceFn(const char* name, State* state, int argc, Expr* argv[]);
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// Convenience function for building expressions with a fixed number
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// of arguments.
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Expr* Build(Function fn, YYLTYPE loc, int count, ...);
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// Global builtins, registered by RegisterBuiltins().
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char* IfElseFn(const char* name, State* state, int argc, Expr* argv[]);
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char* AssertFn(const char* name, State* state, int argc, Expr* argv[]);
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char* AbortFn(const char* name, State* state, int argc, Expr* argv[]);
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// For setting and getting the global error string (when returning
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// NULL from a function).
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void SetError(const char* message); // makes a copy
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const char* GetError(); // retains ownership
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void ClearError();
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typedef struct {
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const char* name;
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Function fn;
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} NamedFunction;
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// Register a new function. The same Function may be registered under
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// multiple names, but a given name should only be used once.
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void RegisterFunction(const char* name, Function fn);
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// Register all the builtins.
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void RegisterBuiltins();
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// Call this after all calls to RegisterFunction() but before parsing
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// any scripts to finish building the function table.
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void FinishRegistration();
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// Find the Function for a given name; return NULL if no such function
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// exists.
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Function FindFunction(const char* name);
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// --- convenience functions for use in functions ---
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// Evaluate the expressions in argv, giving 'count' char* (the ... is
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// zero or more char** to put them in). If any expression evaluates
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// to NULL, free the rest and return -1. Return 0 on success.
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int ReadArgs(State* state, Expr* argv[], int count, ...);
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// Evaluate the expressions in argv, returning an array of char*
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// results. If any evaluate to NULL, free the rest and return NULL.
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// The caller is responsible for freeing the returned array and the
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// strings it contains.
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char** ReadVarArgs(State* state, int argc, Expr* argv[]);
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#endif // _EXPRESSION_H
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