Move libcutils source to C++.

Just the minimial changes to get this to actually build, because otherwise
we always bog down trying to rewrite everything (when the real answer
is usually "stop using libcutils, it's awful").

This doesn't move a handful of files: two are basically just BSD libc
source, a couple have outstanding code reviews, and one can be deleted
(but I'll do that in a separate change).

I'm also skipping the presubmit hooks because otherwise clang-format
wants to reformat everything. I'll follow up with that...

Bug: N/A
Test: builds
Change-Id: I06403f465b67c8e493bad466dd76b1151eed5993

1 files changed, 328 insertions, 0 deletions

diff --git a/libcutils/config_utils.cpp b/libcutils/config_utils.cpp
new file mode 100644
index 000000000..a3af01a58
--- /dev/null
+++ b/libcutils/config_utils.cpp
@@ -0,0 +1,328 @@
+/*
+ * Copyright (C) 2007 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 <cutils/config_utils.h>
+
+#include <string.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <cutils/misc.h>
+
+cnode* config_node(const char *name, const char *value)
+{
+    cnode* node = static_cast<cnode*>(calloc(sizeof(cnode), 1));
+    if(node) {
+        node->name = name ? name : "";
+        node->value = value ? value : "";
+    }
+
+    return node;
+}
+
+cnode* config_find(cnode *root, const char *name)
+{
+    cnode *node, *match = NULL;
+
+    /* we walk the whole list, as we need to return the last (newest) entry */
+    for(node = root->first_child; node; node = node->next)
+        if(!strcmp(node->name, name))
+            match = node;
+
+    return match;
+}
+
+static cnode* _config_create(cnode *root, const char *name)
+{
+    cnode *node;
+
+    node = config_node(name, NULL);
+
+    if(root->last_child)
+        root->last_child->next = node;
+    else
+        root->first_child = node;
+
+    root->last_child = node;
+
+    return node;
+}
+
+int config_bool(cnode *root, const char *name, int _default)
+{
+    cnode *node;
+        
+    node = config_find(root, name);
+    if(!node)
+        return _default;
+
+    switch(node->value[0]) {
+    case 'y':
+    case 'Y':
+    case '1':
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+const char* config_str(cnode *root, const char *name, const char *_default)
+{
+    cnode *node;
+
+    node = config_find(root, name);
+    if(!node)
+        return _default;
+    return node->value;
+}
+
+void config_set(cnode *root, const char *name, const char *value)
+{
+    cnode *node;
+
+    node = config_find(root, name);
+    if(node)
+        node->value = value;
+    else {
+        node = _config_create(root, name);
+        node->value = value;
+    }
+}
+
+#define T_EOF 0
+#define T_TEXT 1
+#define T_DOT 2
+#define T_OBRACE 3
+#define T_CBRACE 4
+
+typedef struct
+{
+    char *data;
+    char *text;
+    int len;
+    char next;
+} cstate;
+
+static int _lex(cstate *cs, int value)
+{
+    char c;
+    char *s;
+    char *data;
+
+    data = cs->data;
+
+    if(cs->next != 0) {
+        c = cs->next;
+        cs->next = 0;
+        goto got_c;
+    }
+
+restart:
+    for(;;) {
+        c = *data++;
+    got_c:
+        if(isspace(c))
+            continue;
+
+        switch(c) {
+        case 0:
+            return T_EOF;
+
+        case '#':
+            for(;;) {
+                switch(*data) {
+                case 0:
+                    cs->data = data;
+                    return T_EOF;
+                case '\n':
+                    cs->data = data + 1;
+                    goto restart;
+                default:
+                    data++;
+                }
+            }
+            break;
+            
+        case '.':
+            cs->data = data;
+            return T_DOT;
+
+        case '{':
+            cs->data = data;
+            return T_OBRACE;
+
+        case '}':
+            cs->data = data;
+            return T_CBRACE;
+
+        default:
+            s = data - 1;
+
+            if(value) {
+                for(;;) {
+                    if(*data == 0) {
+                        cs->data = data;
+                        break;
+                    }
+                    if(*data == '\n') {
+                        cs->data = data + 1;
+                        *data-- = 0;
+                        break;
+                    }
+                    data++;
+                }
+
+                    /* strip trailing whitespace */
+                while(data > s){
+                    if(!isspace(*data)) break;
+                    *data-- = 0;
+                }
+
+                goto got_text;                
+            } else {
+                for(;;) {
+                    if(isspace(*data)) {
+                        *data = 0;
+                        cs->data = data + 1;
+                        goto got_text;
+                    }
+                    switch(*data) {
+                    case 0:
+                        cs->data = data;
+                        goto got_text;
+                    case '.':
+                    case '{':
+                    case '}':
+                        cs->next = *data;
+                        *data = 0;
+                        cs->data = data + 1;
+                        goto got_text;
+                    default:
+                        data++;
+                    }
+                }
+            }
+        }
+    }
+
+got_text:
+    cs->text = s;
+    return T_TEXT;
+}
+
+#if 0
+char *TOKENNAMES[] = { "EOF", "TEXT", "DOT", "OBRACE", "CBRACE" };
+
+static int lex(cstate *cs, int value)
+{
+    int tok = _lex(cs, value);
+    printf("TOKEN(%d) %s %s\n", value, TOKENNAMES[tok],
+           tok == T_TEXT ? cs->text : "");
+    return tok;
+}
+#else
+#define lex(cs,v) _lex(cs,v)
+#endif
+
+static int parse_expr(cstate *cs, cnode *node);
+
+static int parse_block(cstate *cs, cnode *node)
+{
+    for(;;){
+        switch(lex(cs, 0)){
+        case T_TEXT:
+            if(parse_expr(cs, node)) return -1;
+            continue;
+
+        case T_CBRACE:
+            return 0;
+
+        default:
+            return -1;
+        }
+    }
+}
+
+static int parse_expr(cstate *cs, cnode *root)
+{
+    cnode *node;
+
+        /* last token was T_TEXT */
+    node = config_find(root, cs->text);
+    if(!node || *node->value)
+        node = _config_create(root, cs->text);
+
+    for(;;) {
+        switch(lex(cs, 1)) {
+        case T_DOT:
+            if(lex(cs, 0) != T_TEXT)
+                return -1;
+            node = _config_create(node, cs->text);
+            continue;
+
+        case T_TEXT:
+            node->value = cs->text;
+            return 0;
+
+        case T_OBRACE:
+            return parse_block(cs, node);
+
+        default:
+            return -1;
+        }
+    }
+}
+
+void config_load(cnode *root, char *data)
+{
+    if(data != 0) {
+        cstate cs;
+        cs.data = data;
+        cs.next = 0;
+
+        for(;;) {
+            switch(lex(&cs, 0)) {
+            case T_TEXT:
+                if(parse_expr(&cs, root))
+                    return;
+                break;
+            default:
+                return;
+            }
+        }
+    }
+}
+
+void config_load_file(cnode *root, const char *fn)
+{
+    char* data = static_cast<char*>(load_file(fn, nullptr));
+    config_load(root, data);
+    // TODO: deliberate leak :-/
+}
+
+void config_free(cnode *root)
+{
+    cnode *cur = root->first_child;
+
+    while (cur) {
+        cnode *prev = cur;
+        config_free(cur);
+        cur = cur->next;
+        free(prev);
+    }
+}