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

tools/split-select/RuleGenerator.cpp

@@ -0,0 +1,153 @@
+/*
+ * 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 "RuleGenerator.h"
+
+#include <algorithm>
+#include <cmath>
+#include <vector>
+#include <androidfw/ResourceTypes.h>
+
+using namespace android;
+
+namespace split {
+
+// Calculate the point at which the density selection changes between l and h.
+static inline int findMid(int l, int h) {
+    double root = sqrt((h*h) + (8*l*h));
+    return (double(-h) + root) / 2.0;
+}
+
+sp<Rule> RuleGenerator::generateDensity(const Vector<int>& allDensities, size_t index) {
+    sp<Rule> densityRule = new Rule();
+    densityRule->op = Rule::AND_SUBRULES;
+
+    const bool anyDensity = allDensities[index] == ResTable_config::DENSITY_ANY;
+    sp<Rule> any = new Rule();
+    any->op = Rule::EQUALS;
+    any->key = Rule::SCREEN_DENSITY;
+    any->longArgs.add((int)ResTable_config::DENSITY_ANY);
+    any->negate = !anyDensity;
+    densityRule->subrules.add(any);
+
+    if (!anyDensity) {
+        if (index > 0) {
+            sp<Rule> gt = new Rule();
+            gt->op = Rule::GREATER_THAN;
+            gt->key = Rule::SCREEN_DENSITY;
+            gt->longArgs.add(findMid(allDensities[index - 1], allDensities[index]) - 1);
+            densityRule->subrules.add(gt);
+        }
+
+        if (index + 1 < allDensities.size() && allDensities[index + 1] != ResTable_config::DENSITY_ANY) {
+            sp<Rule> lt = new Rule();
+            lt->op = Rule::LESS_THAN;
+            lt->key = Rule::SCREEN_DENSITY;
+            lt->longArgs.add(findMid(allDensities[index], allDensities[index + 1]));
+            densityRule->subrules.add(lt);
+        }
+    }
+    return densityRule;
+}
+
+sp<Rule> RuleGenerator::generateAbi(const Vector<abi::Variant>& splitAbis, size_t index) {
+    const abi::Variant thisAbi = splitAbis[index];
+    const std::vector<abi::Variant>& familyVariants = abi::getVariants(abi::getFamily(thisAbi));
+
+    std::vector<abi::Variant>::const_iterator start =
+            std::find(familyVariants.begin(), familyVariants.end(), thisAbi);
+
+    std::vector<abi::Variant>::const_iterator end = familyVariants.end();
+    if (index + 1 < splitAbis.size()) {
+        end = std::find(start, familyVariants.end(), splitAbis[index + 1]);
+    }
+
+    sp<Rule> abiRule = new Rule();
+    abiRule->op = Rule::CONTAINS_ANY;
+    abiRule->key = Rule::NATIVE_PLATFORM;
+    while (start != end) {
+        abiRule->stringArgs.add(String8(abi::toString(*start)));
+        ++start;
+    }
+    return abiRule;
+}
+
+sp<Rule> RuleGenerator::generate(const SortedVector<SplitDescription>& group, size_t index) {
+    sp<Rule> rootRule = new Rule();
+    rootRule->op = Rule::AND_SUBRULES;
+
+    if (group[index].config.locale != 0) {
+        sp<Rule> locale = new Rule();
+        locale->op = Rule::EQUALS;
+        locale->key = Rule::LANGUAGE;
+        char str[RESTABLE_MAX_LOCALE_LEN];
+        group[index].config.getBcp47Locale(str);
+        locale->stringArgs.add(String8(str));
+        rootRule->subrules.add(locale);
+    }
+
+    if (group[index].config.sdkVersion != 0) {
+        sp<Rule> sdk = new Rule();
+        sdk->op = Rule::GREATER_THAN;
+        sdk->key = Rule::SDK_VERSION;
+        sdk->longArgs.add(group[index].config.sdkVersion - 1);
+        rootRule->subrules.add(sdk);
+    }
+
+    if (group[index].config.density != 0) {
+        size_t densityIndex = 0;
+        Vector<int> allDensities;
+        allDensities.add(group[index].config.density);
+
+        const size_t groupSize = group.size();
+        for (size_t i = 0; i < groupSize; i++) {
+            if (group[i].config.density != group[index].config.density) {
+                // This group differs by density.
+                allDensities.clear();
+                for (size_t j = 0; j < groupSize; j++) {
+                    allDensities.add(group[j].config.density);
+                }
+                densityIndex = index;
+                break;
+            }
+        }
+        rootRule->subrules.add(generateDensity(allDensities, densityIndex));
+    }
+
+    if (group[index].abi != abi::Variant::none) {
+        size_t abiIndex = 0;
+        Vector<abi::Variant> allVariants;
+        allVariants.add(group[index].abi);
+
+        const size_t groupSize = group.size();
+        for (size_t i = 0; i < groupSize; i++) {
+            if (group[i].abi != group[index].abi) {
+                // This group differs by ABI.
+                allVariants.clear();
+                for (size_t j = 0; j < groupSize; j++) {
+                    allVariants.add(group[j].abi);
+                }
+                abiIndex = index;
+                break;
+            }
+        }
+        rootRule->subrules.add(generateAbi(allVariants, abiIndex));
+    }
+
+    return rootRule;
+}
+
+} // namespace split