First commit of split-select tool

This tool emits a set of rules as JSON for when a Split APK
should match a target device.

Change-Id: I8bfbdfbdb51efcfc645889dd03e1961f16e39645
diff --git a/tools/split-select/Rule.cpp b/tools/split-select/Rule.cpp
new file mode 100644
index 0000000..9559fe2
--- /dev/null
+++ b/tools/split-select/Rule.cpp
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2014 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 "Rule.h"
+
+#include <utils/String8.h>
+
+using namespace android;
+
+namespace split {
+
+inline static void indentStr(String8& str, int indent) {
+    while (indent > 0) {
+        str.append("  ");
+        indent--;
+    }
+}
+
+String8 Rule::toJson(int indent) const {
+    String8 str;
+    indentStr(str, indent);
+    str.append("{\n");
+    indent++;
+    indentStr(str, indent);
+    str.append("\"op\": \"");
+    switch (op) {
+        case ALWAYS_TRUE:
+            str.append("ALWAYS_TRUE");
+            break;
+        case GREATER_THAN:
+            str.append("GREATER_THAN");
+            break;
+        case LESS_THAN:
+            str.append("LESS_THAN");
+            break;
+        case EQUALS:
+            str.append("EQUALS");
+            break;
+        case AND_SUBRULES:
+            str.append("AND_SUBRULES");
+            break;
+        case OR_SUBRULES:
+            str.append("OR_SUBRULES");
+            break;
+        case CONTAINS_ANY:
+            str.append("CONTAINS_ANY");
+            break;
+        default:
+            str.appendFormat("%d", op);
+            break;
+    }
+    str.append("\"");
+
+    if (negate) {
+        str.append(",\n");
+        indentStr(str, indent);
+        str.append("\"negate\": true");
+    }
+
+    bool includeKey = true;
+    switch (op) {
+        case AND_SUBRULES:
+        case OR_SUBRULES:
+            includeKey = false;
+            break;
+        default:
+            break;
+    }
+
+    if (includeKey) {
+        str.append(",\n");
+        indentStr(str, indent);
+        str.append("\"property\": \"");
+        switch (key) {
+            case NONE:
+                str.append("NONE");
+                break;
+            case SDK_VERSION:
+                str.append("SDK_VERSION");
+                break;
+            case SCREEN_DENSITY:
+                str.append("SCREEN_DENSITY");
+                break;
+            case NATIVE_PLATFORM:
+                str.append("NATIVE_PLATFORM");
+                break;
+            case LANGUAGE:
+                str.append("LANGUAGE");
+                break;
+            default:
+                str.appendFormat("%d", key);
+                break;
+        }
+        str.append("\"");
+    }
+
+    if (op == AND_SUBRULES || op == OR_SUBRULES) {
+        str.append(",\n");
+        indentStr(str, indent);
+        str.append("\"subrules\": [\n");
+        const size_t subruleCount = subrules.size();
+        for (size_t i = 0; i < subruleCount; i++) {
+            str.append(subrules[i]->toJson(indent + 1));
+            if (i != subruleCount - 1) {
+                str.append(",");
+            }
+            str.append("\n");
+        }
+        indentStr(str, indent);
+        str.append("]");
+    } else {
+        switch (key) {
+            case SDK_VERSION:
+            case SCREEN_DENSITY: {
+                str.append(",\n");
+                indentStr(str, indent);
+                str.append("\"args\": [");
+                const size_t argCount = longArgs.size();
+                for (size_t i = 0; i < argCount; i++) {
+                    if (i != 0) {
+                        str.append(", ");
+                    }
+                    str.appendFormat("%d", longArgs[i]);
+                }
+                str.append("]");
+                break;
+            }
+            case LANGUAGE:
+            case NATIVE_PLATFORM: {
+                str.append(",\n");
+                indentStr(str, indent);
+                str.append("\"args\": [");
+                const size_t argCount = stringArgs.size();
+                for (size_t i = 0; i < argCount; i++) {
+                    if (i != 0) {
+                        str.append(", ");
+                    }
+                    str.append(stringArgs[i]);
+                }
+                str.append("]");
+                break;
+            }
+            default:
+                break;
+        }
+    }
+    str.append("\n");
+    indent--;
+    indentStr(str, indent);
+    str.append("}");
+    return str;
+}
+
+sp<Rule> Rule::simplify(sp<Rule> rule) {
+    if (rule->op != AND_SUBRULES && rule->op != OR_SUBRULES) {
+        return rule;
+    }
+
+    Vector<sp<Rule> > newSubrules;
+    newSubrules.setCapacity(rule->subrules.size());
+    const size_t subruleCount = rule->subrules.size();
+    for (size_t i = 0; i < subruleCount; i++) {
+        sp<Rule> simplifiedRule = simplify(rule->subrules.editItemAt(i));
+        if (simplifiedRule != NULL) {
+            if (simplifiedRule->op == rule->op) {
+                newSubrules.appendVector(simplifiedRule->subrules);
+            } else {
+                newSubrules.add(simplifiedRule);
+            }
+        }
+    }
+
+    const size_t newSubruleCount = newSubrules.size();
+    if (newSubruleCount == 0) {
+        return NULL;
+    } else if (subruleCount == 1) {
+        return newSubrules.editTop();
+    }
+    rule->subrules = newSubrules;
+    return rule;
+}
+
+} // namespace split