SERVER-1534 $min/$max update mods

4 files changed, 574 insertions, 0 deletions

diff --git a/src/mongo/db/ops/SConscript b/src/mongo/db/ops/SConscript
index c75c6dd5182..eb9ccaef935 100644
--- a/src/mongo/db/ops/SConscript
+++ b/src/mongo/db/ops/SConscript
@@ -53,6 +53,7 @@ env.StaticLibrary(
     source=[
         'modifier_add_to_set.cpp',
         'modifier_bit.cpp',
+        'modifier_compare.cpp',
         'modifier_inc.cpp',
         'modifier_object_replace.cpp',
         'modifier_pop.cpp',
@@ -88,6 +89,15 @@ env.CppUnitTest(
 )
 
 env.CppUnitTest(
+    target='modifier_compare_test',
+    source='modifier_compare_test.cpp',
+    LIBDEPS=[
+        '$BUILD_DIR/mongo/mutable_bson_test_utils',
+        'update',
+    ],
+)
+
+env.CppUnitTest(
     target='modifier_inc_test',
     source='modifier_inc_test.cpp',
     LIBDEPS=[
diff --git a/src/mongo/db/ops/modifier_compare.cpp b/src/mongo/db/ops/modifier_compare.cpp
new file mode 100644
index 00000000000..4942e8f6b1b
--- /dev/null
+++ b/src/mongo/db/ops/modifier_compare.cpp
@@ -0,0 +1,170 @@
+/**
+ *    Copyright (C) 2013 10gen Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "mongo/db/ops/modifier_compare.h"
+
+#include "mongo/base/error_codes.h"
+#include "mongo/bson/mutable/document.h"
+#include "mongo/db/ops/field_checker.h"
+#include "mongo/db/ops/log_builder.h"
+#include "mongo/db/ops/path_support.h"
+
+namespace mongo {
+
+
+    struct ModifierCompare::PreparedState {
+
+        PreparedState(mutablebson::Document& targetDoc)
+            : doc(targetDoc)
+            , idxFound(0)
+            , elemFound(doc.end()) {
+        }
+
+        // Document that is going to be changed.
+        mutablebson::Document& doc;
+
+        // Index in _fieldRef for which an Element exist in the document.
+        size_t idxFound;
+
+        // Element corresponding to _fieldRef[0.._idxFound].
+        mutablebson::Element elemFound;
+
+        // The replacement string passed in via prepare
+        std::string pathReplacementString;
+    };
+
+    ModifierCompare::ModifierCompare(ModifierCompare::ModifierCompareMode mode)
+        : _mode(mode)
+        , _pathReplacementPosition(0) {
+    }
+
+    ModifierCompare::~ModifierCompare() {
+    }
+
+    Status ModifierCompare::init(const BSONElement& modExpr, const Options& opts) {
+        _updatePath.parse(modExpr.fieldName());
+        Status status = fieldchecker::isUpdatable(_updatePath);
+        if (!status.isOK()) {
+            return status;
+        }
+
+        // If a $-positional operator was used, get the index in which it occurred
+        // and ensure only one occurrence.
+        size_t foundCount;
+        fieldchecker::isPositional(_updatePath, &_pathReplacementPosition, &foundCount);
+        if (_pathReplacementPosition && foundCount > 1) {
+            return Status(ErrorCodes::BadValue, "too many positional($) elements found.");
+        }
+
+        // Store value for later.
+        _val = modExpr;
+        return Status::OK();
+    }
+
+    Status ModifierCompare::prepare(mutablebson::Element root,
+                                const StringData& matchedField,
+                                ExecInfo* execInfo) {
+
+        _preparedState.reset(new PreparedState(root.getDocument()));
+
+        // If we have a $-positional field, it is time to bind it to an actual field part.
+        if (_pathReplacementPosition) {
+            if (matchedField.empty()) {
+                return Status(ErrorCodes::BadValue, "matched field not provided");
+            }
+            _preparedState->pathReplacementString = matchedField.toString();
+            _updatePath.setPart(_pathReplacementPosition, _preparedState->pathReplacementString);
+        }
+
+        // Locate the field name in 'root'. Note that we may not have all the parts in the path
+        // in the doc -- which is fine. Our goal now is merely to reason about whether this mod
+        // apply is a noOp or whether is can be in place. The remaining path, if missing, will
+        // be created during the apply.
+        Status status = pathsupport::findLongestPrefix(_updatePath,
+                                                       root,
+                                                       &_preparedState->idxFound,
+                                                       &_preparedState->elemFound);
+
+        // FindLongestPrefix may say the path does not exist at all, which is fine here, or
+        // that the path was not viable or otherwise wrong, in which case, the mod cannot
+        // proceed.
+        if (status.code() == ErrorCodes::NonExistentPath) {
+            _preparedState->elemFound = root.getDocument().end();
+        }
+        else if (!status.isOK()) {
+            return status;
+        }
+
+        // We register interest in the field name. The driver needs this info to sort out if
+        // there is any conflict among mods.
+        execInfo->fieldRef[0] = &_updatePath;
+
+        const bool destExists = (_preparedState->elemFound.ok() &&
+                                 _preparedState->idxFound == (_updatePath.numParts() - 1));
+        if (!destExists) {
+            execInfo->noOp = false;
+        }
+        else {
+            const int compareVal = _preparedState->elemFound.compareWithBSONElement(_val, false);
+            execInfo->noOp = (compareVal == 0) ||
+                             ((_mode == ModifierCompare::MAX) ?
+                                     (compareVal > 0) : (compareVal < 0));
+        }
+
+        return Status::OK();
+    }
+
+    Status ModifierCompare::apply() const {
+
+        const bool destExists = (_preparedState->elemFound.ok() &&
+                                 _preparedState->idxFound == (_updatePath.numParts() - 1));
+        // If there's no need to create any further field part, the $set is simply a value
+        // assignment.
+        if (destExists) {
+            return _preparedState->elemFound.setValueBSONElement(_val);
+        }
+
+        mutablebson::Document& doc = _preparedState->doc;
+        StringData lastPart = _updatePath.getPart(_updatePath.numParts() - 1);
+        // If the element exists and is the same type, then that is what we want to work with
+        mutablebson::Element elemToSet = doc.makeElementWithNewFieldName(lastPart, _val);
+        if (!elemToSet.ok()) {
+            return Status(ErrorCodes::InternalError, "can't create new element");
+        }
+
+        // Now, we can be in two cases here, as far as attaching the element being set goes:
+        // (a) none of the parts in the element's path exist, or (b) some parts of the path
+        // exist but not all.
+        if (!_preparedState->elemFound.ok()) {
+            _preparedState->elemFound = doc.root();
+            _preparedState->idxFound = 0;
+        }
+        else {
+            _preparedState->idxFound++;
+        }
+
+        // createPathAt() will complete the path and attach 'elemToSet' at the end of it.
+        return pathsupport::createPathAt(_updatePath,
+                                         _preparedState->idxFound,
+                                         _preparedState->elemFound,
+                                         elemToSet);
+    }
+
+    Status ModifierCompare::log(LogBuilder* logBuilder) const {
+        return logBuilder->addToSetsWithNewFieldName(_updatePath.dottedField(), _val);
+    }
+
+} // namespace mongo
diff --git a/src/mongo/db/ops/modifier_compare.h b/src/mongo/db/ops/modifier_compare.h
new file mode 100644
index 00000000000..ceec02bdc37
--- /dev/null
+++ b/src/mongo/db/ops/modifier_compare.h
@@ -0,0 +1,98 @@
+/**
+ *    Copyright (C) 2013 10gen Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <boost/scoped_ptr.hpp>
+#include <string>
+
+#include "mongo/base/disallow_copying.h"
+#include "mongo/bson/mutable/element.h"
+#include "mongo/db/field_ref.h"
+#include "mongo/db/jsobj.h"
+#include "mongo/db/ops/modifier_interface.h"
+
+namespace mongo {
+
+    class LogBuilder;
+
+    class ModifierCompare : public ModifierInterface {
+        MONGO_DISALLOW_COPYING(ModifierCompare);
+
+    public:
+
+        enum ModifierCompareMode { MAX, MIN };
+        explicit ModifierCompare(ModifierCompareMode mode = MAX);
+
+        virtual ~ModifierCompare();
+
+        //
+        // Modifier interface implementation
+        //
+
+        /**
+         * A 'modExpr' is a BSONElement {<fieldname>: <value>} coming from a $set mod such as
+         * {$set: {<fieldname: <value>}}. init() extracts the field name and the value to be
+         * assigned to it from 'modExpr'. It returns OK if successful or a status describing
+         * the error.
+         */
+        virtual Status init(const BSONElement& modExpr, const Options& opts);
+
+        /**
+         * Looks up the field name in the sub-tree rooted at 'root', and binds, if necessary,
+         * the '$' field part using the 'matchedfield' number. prepare() returns OK and
+         * fills in 'execInfo' with information of whether this mod is a no-op on 'root' and
+         * whether it is an in-place candidate. Otherwise, returns a status describing the
+         * error.
+         */
+        virtual Status prepare(mutablebson::Element root,
+                               const StringData& matchedField,
+                               ExecInfo* execInfo);
+
+        /**
+         * Applies the prepared mod over the element 'root' specified in the prepare()
+         * call. Returns OK if successful or a status describing the error.
+         */
+        virtual Status apply() const;
+
+        /**
+         * Adds a log entry to logRoot corresponding to the operation applied here. Returns OK
+         * if successful or a status describing the error.
+         */
+        virtual Status log(LogBuilder* logBuilder) const;
+
+    private:
+
+        // Compare mode: min/max
+        const ModifierCompareMode _mode;
+
+        // Access to each component of fieldName that's the target of this mod.
+        FieldRef _updatePath;
+
+        // 0 or index for $-positional in _updatePath.
+        size_t _pathReplacementPosition;
+
+        // Element of the mod expression.
+        BSONElement _val;
+
+        // The instance of the field in the provided doc. This state is valid after a
+        // prepare() was issued and until a log() is issued. The document this mod is
+        // being prepared against must be live throughout all the calls.
+        struct PreparedState;
+        scoped_ptr<PreparedState> _preparedState;
+    };
+
+} // namespace mongo
diff --git a/src/mongo/db/ops/modifier_compare_test.cpp b/src/mongo/db/ops/modifier_compare_test.cpp
new file mode 100644
index 00000000000..eba04776b1f
--- /dev/null
+++ b/src/mongo/db/ops/modifier_compare_test.cpp
@@ -0,0 +1,296 @@
+/**
+ *    Copyright (C) 2013 10gen Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/ops/modifier_compare.h"
+
+#include "mongo/base/string_data.h"
+#include "mongo/bson/mutable/document.h"
+#include "mongo/bson/mutable/mutable_bson_test_utils.h"
+#include "mongo/db/jsobj.h"
+#include "mongo/db/json.h"
+#include "mongo/db/ops/log_builder.h"
+#include "mongo/platform/cstdint.h"
+#include "mongo/unittest/unittest.h"
+
+namespace {
+
+    using mongo::BSONObj;
+    using mongo::LogBuilder;
+    using mongo::ModifierCompare;
+    using mongo::ModifierInterface;
+    using mongo::Status;
+    using mongo::StringData;
+    using mongo::fromjson;
+    using mongo::mutablebson::ConstElement;
+    using mongo::mutablebson::Document;
+    using mongo::mutablebson::Element;
+
+    const char kModNameMin[] = "$min";
+    const char kModNameMax[] = "$max";
+
+    /** Helper to build and manipulate a $min/max mod. */
+    class Mod {
+    public:
+        Mod() : _mod() {}
+
+        explicit Mod(BSONObj modObj)
+            : _modObj(modObj)
+            , _mod((modObj.firstElement().fieldNameStringData() == "$min") ?
+                                                                ModifierCompare::MIN :
+                                                                ModifierCompare::MAX) {
+            const StringData& modName = modObj.firstElement().fieldName();
+            ASSERT_OK(_mod.init(modObj[modName].embeddedObject().firstElement(),
+                                ModifierInterface::Options::normal()));
+        }
+
+        Status prepare(Element root,
+                       const StringData& matchedField,
+                       ModifierInterface::ExecInfo* execInfo) {
+            return _mod.prepare(root, matchedField, execInfo);
+        }
+
+        Status apply() const {
+            return _mod.apply();
+        }
+
+        Status log(LogBuilder* logBuilder) const {
+            return _mod.log(logBuilder);
+        }
+
+        ModifierCompare& mod() { return _mod; }
+
+    private:
+        BSONObj _modObj;
+        ModifierCompare _mod;
+    };
+
+    TEST(Init, ValidValues) {
+        BSONObj modObj;
+        ModifierCompare mod;
+
+        modObj = fromjson("{ $min : { a : 2 } }");
+        ASSERT_OK(mod.init(modObj[kModNameMin].embeddedObject().firstElement(),
+                               ModifierInterface::Options::normal()));
+
+        modObj = fromjson("{ $max : { a : 1 } }");
+        ASSERT_OK(mod.init(modObj[kModNameMax].embeddedObject().firstElement(),
+                               ModifierInterface::Options::normal()));
+
+        modObj = fromjson("{ $min : { a : {$date : 0 } } }");
+        ASSERT_OK(mod.init(modObj[kModNameMin].embeddedObject().firstElement(),
+                               ModifierInterface::Options::normal()));
+    }
+
+    TEST(ExistingNumber, MaxSameNumber) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$max: {a: 1} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingNumber, MinSameNumber) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$min: {a: 1} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingNumber, MaxNumberIsLess) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$max: {a: 0} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingNumber, MinNumberIsMore) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$min: {a: 2} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingDouble, MaxSameValInt) {
+        Document doc(fromjson("{a: 1.0 }"));
+        Mod mod(BSON("$max" << BSON("a" << 1LL)));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingDoubleZero, MaxSameValIntZero) {
+        Document doc(fromjson("{a: 0.0 }"));
+        Mod mod(BSON("$max" << BSON("a" << 0LL)));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(ExistingDoubleZero, MinSameValIntZero) {
+        Document doc(fromjson("{a: 0.0 }"));
+        Mod mod(BSON("$min" << BSON("a" << 0LL)));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+    }
+
+    TEST(MissingField, MinNumber) {
+        Document doc(fromjson("{}"));
+        Mod mod(fromjson("{$min: {a: 0} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a : 0}"), doc);
+        ASSERT_FALSE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{ $set : { a : 0 } }"), logDoc);
+    }
+
+    TEST(ExistingNumber, MinNumber) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$min: {a: 0} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a : 0}"), doc);
+        ASSERT_TRUE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{ $set : { a : 0 } }"), logDoc);
+    }
+
+    TEST(MissingField, MaxNumber) {
+        Document doc(fromjson("{}"));
+        Mod mod(fromjson("{$max: {a: 0} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a : 0}"), doc);
+        ASSERT_FALSE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{ $set : { a : 0 } }"), logDoc);
+    }
+
+    TEST(ExistingNumber, MaxNumber) {
+        Document doc(fromjson("{a: 1 }"));
+        Mod mod(fromjson("{$max: {a: 2} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a : 2}"), doc);
+        ASSERT_TRUE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{ $set : { a : 2 } }"), logDoc);
+    }
+
+    TEST(ExistingDate, MaxDate) {
+        Document doc(fromjson("{a: {$date: 0} }"));
+        Mod mod(fromjson("{$max: {a: {$date: 123123123}} }"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a: {$date: 123123123}}"), doc);
+        ASSERT_TRUE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{$set: {a: {$date: 123123123}} }"), logDoc);
+    }
+
+    TEST(ExistingEmbeddedDoc, MaxDoc) {
+        Document doc(fromjson("{a: {b: 2}}"));
+        Mod mod(fromjson("{$max: {a: {b: 3}}}"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_FALSE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+
+        ASSERT_OK(mod.apply());
+        ASSERT_EQUALS(fromjson("{a: {b: 3}}}"), doc);
+        ASSERT_FALSE(doc.isInPlaceModeEnabled());
+
+        Document logDoc;
+        LogBuilder logBuilder(logDoc.root());
+        ASSERT_OK(mod.log(&logBuilder));
+        ASSERT_EQUALS(fromjson("{$set: {a: {b: 3}} }"), logDoc);
+    }
+
+    TEST(ExistingEmbeddedDoc, MaxNumber) {
+        Document doc(fromjson("{a: {b: 2}}"));
+        Mod mod(fromjson("{$max: {a: 3}}"));
+
+        ModifierInterface::ExecInfo execInfo;
+        ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
+        ASSERT_TRUE(execInfo.noOp);
+        ASSERT_EQUALS("a", execInfo.fieldRef[0]->dottedField());
+    }
+
+} // namespace