core of edify, an eventual replacement for amend
Edify is a simple scripting language for OTA installation, to be used
when we move to OTAs being installed via binaries shipped with the
package.
diff --git a/edify/expr.c b/edify/expr.c
new file mode 100644
index 0000000..b3b8927
--- /dev/null
+++ b/edify/expr.c
@@ -0,0 +1,279 @@
+/*
+ * 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 <string.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "expr.h"
+
+// Functions should:
+//
+// - return a malloc()'d string
+// - if Evaluate() on any argument returns NULL, return NULL.
+
+int BooleanString(const char* s) {
+ return s[0] != '\0';
+}
+
+char* Evaluate(void* cookie, Expr* expr) {
+ return expr->fn(expr->name, cookie, expr->argc, expr->argv);
+}
+
+char* ConcatFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ if (argc == 0) {
+ return strdup("");
+ }
+ char** strings = malloc(argc * sizeof(char*));
+ int i;
+ for (i = 0; i < argc; ++i) {
+ strings[i] = NULL;
+ }
+ char* result = NULL;
+ int length = 0;
+ for (i = 0; i < argc; ++i) {
+ strings[i] = Evaluate(cookie, argv[i]);
+ if (strings[i] == NULL) {
+ goto done;
+ }
+ length += strlen(strings[i]);
+ }
+
+ result = malloc(length+1);
+ int p = 0;
+ for (i = 0; i < argc; ++i) {
+ strcpy(result+p, strings[i]);
+ p += strlen(strings[i]);
+ }
+ result[p] = '\0';
+
+done:
+ for (i = 0; i < argc; ++i) {
+ free(strings[i]);
+ }
+ return result;
+}
+
+char* IfElseFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ if (argc != 2 && argc != 3) {
+ return NULL;
+ }
+ char* cond = Evaluate(cookie, argv[0]);
+ if (cond == NULL) {
+ return NULL;
+ }
+
+ if (BooleanString(cond) == true) {
+ free(cond);
+ return Evaluate(cookie, argv[1]);
+ } else {
+ if (argc == 3) {
+ free(cond);
+ return Evaluate(cookie, argv[2]);
+ } else {
+ return cond;
+ }
+ }
+}
+
+char* AbortFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ return NULL;
+}
+
+char* AssertFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ int i;
+ for (i = 0; i < argc; ++i) {
+ char* v = Evaluate(cookie, argv[i]);
+ if (v == NULL) {
+ return NULL;
+ }
+ int b = BooleanString(v);
+ free(v);
+ if (!b) {
+ return NULL;
+ }
+ }
+ return strdup("");
+}
+
+char* PrintFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ int i;
+ for (i = 0; i < argc; ++i) {
+ char* v = Evaluate(cookie, argv[i]);
+ if (v == NULL) {
+ return NULL;
+ }
+ fputs(v, stdout);
+ free(v);
+ }
+ return strdup("");
+}
+
+char* LogicalAndFn(const char* name, void* cookie,
+ int argc, Expr* argv[]) {
+ char* left = Evaluate(cookie, argv[0]);
+ if (left == NULL) return NULL;
+ if (BooleanString(left) == true) {
+ free(left);
+ return Evaluate(cookie, argv[1]);
+ } else {
+ return left;
+ }
+}
+
+char* LogicalOrFn(const char* name, void* cookie,
+ int argc, Expr* argv[]) {
+ char* left = Evaluate(cookie, argv[0]);
+ if (left == NULL) return NULL;
+ if (BooleanString(left) == false) {
+ free(left);
+ return Evaluate(cookie, argv[1]);
+ } else {
+ return left;
+ }
+}
+
+char* LogicalNotFn(const char* name, void* cookie,
+ int argc, Expr* argv[]) {
+ char* val = Evaluate(cookie, argv[0]);
+ if (val == NULL) return NULL;
+ bool bv = BooleanString(val);
+ free(val);
+ if (bv) {
+ return strdup("");
+ } else {
+ return strdup("t");
+ }
+}
+
+char* SubstringFn(const char* name, void* cookie,
+ int argc, Expr* argv[]) {
+ char* needle = Evaluate(cookie, argv[0]);
+ if (needle == NULL) return NULL;
+ char* haystack = Evaluate(cookie, argv[1]);
+ if (haystack == NULL) {
+ free(needle);
+ return NULL;
+ }
+
+ char* result = strdup(strstr(haystack, needle) ? "t" : "");
+ free(needle);
+ free(haystack);
+ return result;
+}
+
+char* EqualityFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ char* left = Evaluate(cookie, argv[0]);
+ if (left == NULL) return NULL;
+ char* right = Evaluate(cookie, argv[1]);
+ if (right == NULL) {
+ free(left);
+ return NULL;
+ }
+
+ char* result = strdup(strcmp(left, right) == 0 ? "t" : "");
+ free(left);
+ free(right);
+ return result;
+}
+
+char* InequalityFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ char* left = Evaluate(cookie, argv[0]);
+ if (left == NULL) return NULL;
+ char* right = Evaluate(cookie, argv[1]);
+ if (right == NULL) {
+ free(left);
+ return NULL;
+ }
+
+ char* result = strdup(strcmp(left, right) != 0 ? "t" : "");
+ free(left);
+ free(right);
+ return result;
+}
+
+char* SequenceFn(const char* name, void* cookie, int argc, Expr* argv[]) {
+ char* left = Evaluate(cookie, argv[0]);
+ if (left == NULL) return NULL;
+ free(left);
+ return Evaluate(cookie, argv[1]);
+}
+
+char* Literal(const char* name, void* cookie, int argc, Expr* argv[]) {
+ return strdup(name);
+}
+
+Expr* Build(Function fn, int count, ...) {
+ va_list v;
+ va_start(v, count);
+ Expr* e = malloc(sizeof(Expr));
+ e->fn = fn;
+ e->name = "(operator)";
+ e->argc = count;
+ e->argv = malloc(count * sizeof(Expr*));
+ int i;
+ for (i = 0; i < count; ++i) {
+ e->argv[i] = va_arg(v, Expr*);
+ }
+ va_end(v);
+ return e;
+}
+
+static int fn_entries = 0;
+static int fn_size = 0;
+NamedFunction* fn_table = NULL;
+
+void RegisterFunction(const char* name, Function fn) {
+ if (fn_entries <= fn_size) {
+ fn_size = fn_size*2 + 1;
+ fn_table = realloc(fn_table, fn_size * sizeof(NamedFunction));
+ }
+ fn_table[fn_entries].name = name;
+ fn_table[fn_entries].fn = fn;
+ ++fn_entries;
+}
+
+static int fn_entry_compare(const void* a, const void* b) {
+ const char* na = ((const NamedFunction*)a)->name;
+ const char* nb = ((const NamedFunction*)b)->name;
+ return strcmp(na, nb);
+}
+
+void FinishRegistration() {
+ qsort(fn_table, fn_entries, sizeof(NamedFunction), fn_entry_compare);
+}
+
+Function FindFunction(const char* name) {
+ NamedFunction key;
+ key.name = name;
+ NamedFunction* nf = bsearch(&key, fn_table, fn_entries, sizeof(NamedFunction),
+ fn_entry_compare);
+ if (nf == NULL) {
+ return NULL;
+ }
+ return nf->fn;
+}
+
+void RegisterBuiltins() {
+ RegisterFunction("ifelse", IfElseFn);
+ RegisterFunction("abort", AbortFn);
+ RegisterFunction("assert", AssertFn);
+ RegisterFunction("concat", ConcatFn);
+ RegisterFunction("is_substring", SubstringFn);
+ RegisterFunction("print", PrintFn);
+}