[realppl 2] Minimalistic ppl offline evaluation

Author: wu-hui

.gitignore

@@ -45,6 +45,7 @@ Secrets.tar
 
 # Xcode
 build/
+.index-build/
 *.pbxuser
 !default.pbxuser
 *.mode1v3

Firestore/Example/Firestore.xcodeproj/project.pbxproj

@@ -19,40 +19,58 @@
 #include <memory>
 
 #include "Firestore/Protos/nanopb/google/firestore/v1/document.nanopb.h"
+#include "Firestore/core/src/core/expressions_eval.h"
 #include "Firestore/core/src/model/value_util.h"
 #include "Firestore/core/src/nanopb/nanopb_util.h"
 
 namespace firebase {
 namespace firestore {
 namespace api {
 
+Field::Field(std::string name) {
+  field_path_ = model::FieldPath::FromDotSeparatedString(name);
+}
+
 google_firestore_v1_Value Field::to_proto() const {
   google_firestore_v1_Value result;
 
   result.which_value_type = google_firestore_v1_Value_field_reference_value_tag;
-  result.field_reference_value = nanopb::MakeBytesArray(this->name_);
+  result.field_reference_value = nanopb::MakeBytesArray(this->alias());
 
   return result;
 }
 
+std::unique_ptr<core::EvaluableExpr> Field::ToEvaluable() const {
+  return std::make_unique<core::CoreField>(std::make_unique<Field>(*this));
+}
+
 google_firestore_v1_Value Constant::to_proto() const {
   // Return a copy of the value proto to avoid double delete.
   return *model::DeepClone(*value_).release();
 }
 
+std::unique_ptr<core::EvaluableExpr> Constant::ToEvaluable() const {
+  return std::make_unique<core::CoreConstant>(
+      std::make_unique<Constant>(*this));
+}
+
 google_firestore_v1_Value FunctionExpr::to_proto() const {
   google_firestore_v1_Value result;
 
   result.which_value_type = google_firestore_v1_Value_function_value_tag;
   result.function_value = google_firestore_v1_Function{};
   result.function_value.name = nanopb::MakeBytesArray(name_);
   nanopb::SetRepeatedField(
-      &result.function_value.args, &result.function_value.args_count, args_,
+      &result.function_value.args, &result.function_value.args_count, params_,
       [](const std::shared_ptr<Expr>& arg) { return arg->to_proto(); });
 
   return result;
 }
 
+std::unique_ptr<core::EvaluableExpr> FunctionExpr::ToEvaluable() const {
+  return core::FunctionToEvaluable(*this);
+}
+
 }  // namespace api
 }  // namespace firestore
 }  // namespace firebase

Firestore/core/src/api/expressions.cc

@@ -23,30 +23,54 @@
 #include <vector>
 
 #include "Firestore/Protos/nanopb/google/firestore/v1/document.nanopb.h"
+#include "Firestore/core/src/model/field_path.h"
 #include "Firestore/core/src/nanopb/message.h"
 
 namespace firebase {
 namespace firestore {
+namespace core {
+class EvaluableExpr;
+}  // namespace core
 namespace api {
 
 class Expr {
  public:
   Expr() = default;
   virtual ~Expr() = default;
   virtual google_firestore_v1_Value to_proto() const = 0;
+  virtual std::unique_ptr<core::EvaluableExpr> ToEvaluable() const = 0;
 };
 
-class Field : public Expr {
+class Selectable : public Expr {
  public:
-  explicit Field(std::string name) : name_(std::move(name)) {
+  virtual ~Selectable() override = default;
+  virtual const std::string& alias() const = 0;
+};
+
+class Field : public Selectable {
+ public:
+  explicit Field(model::FieldPath field_path)
+      : field_path_(std::move(field_path)),
+        alias_(field_path_.CanonicalString()) {
   }
+  ~Field() override = default;
+
+  explicit Field(std::string name);
+
   google_firestore_v1_Value to_proto() const override;
-  const std::string& alias() const {
-    return name_;
+
+  const std::string& alias() const override {
+    return alias_;
   }
+  const model::FieldPath& field_path() const {
+    return field_path_;
+  }
+
+  std::unique_ptr<core::EvaluableExpr> ToEvaluable() const override;
 
  private:
-  std::string name_;
+  model::FieldPath field_path_;
+  std::string alias_;
 };
 
 class Constant : public Expr {
@@ -56,21 +80,33 @@ class Constant : public Expr {
   }
   google_firestore_v1_Value to_proto() const override;
 
+  std::unique_ptr<core::EvaluableExpr> ToEvaluable() const override;
+
  private:
   nanopb::SharedMessage<google_firestore_v1_Value> value_;
 };
 
 class FunctionExpr : public Expr {
  public:
-  FunctionExpr(std::string name, std::vector<std::shared_ptr<Expr>> args)
-      : name_(std::move(name)), args_(std::move(args)) {
+  FunctionExpr(std::string name, std::vector<std::shared_ptr<Expr>> params)
+      : name_(std::move(name)), params_(std::move(params)) {
   }
 
   google_firestore_v1_Value to_proto() const override;
 
+  std::unique_ptr<core::EvaluableExpr> ToEvaluable() const override;
+
+  const std::string& name() const {
+    return name_;
+  }
+
+  const std::vector<std::shared_ptr<Expr>>& params() const {
+    return params_;
+  }
+
  private:
   std::string name_;
-  std::vector<std::shared_ptr<Expr>> args_;
+  std::vector<std::shared_ptr<Expr>> params_;
 };
 
 }  // namespace api

Firestore/core/src/api/expressions.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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 "Firestore/core/src/api/realtime_pipeline.h"
+
+#include <memory>
+#include <utility>
+
+#include "Firestore/core/src/remote/serializer.h"
+
+namespace firebase {
+namespace firestore {
+namespace api {
+
+RealtimePipeline::RealtimePipeline(
+    std::vector<std::shared_ptr<EvaluableStage>> stages,
+    remote::Serializer serializer)
+    : stages_(std::move(stages)), serializer_(std::move(serializer)) {
+}
+
+RealtimePipeline RealtimePipeline::AddingStage(
+    std::shared_ptr<EvaluableStage> stage) {
+  auto copy = std::vector<std::shared_ptr<EvaluableStage>>(this->stages_);
+  copy.push_back(stage);
+
+  return {copy, serializer_};
+}
+
+const std::vector<std::shared_ptr<EvaluableStage>>& RealtimePipeline::stages()
+    const {
+  return this->stages_;
+}
+
+EvaluateContext RealtimePipeline::evaluate_context() {
+  return EvaluateContext(&serializer_);
+}
+
+}  // namespace api
+}  // namespace firestore
+}  // namespace firebase

Firestore/core/src/api/realtime_pipeline.cc

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_API_REALTIME_PIPELINE_H_
+#define FIRESTORE_CORE_SRC_API_REALTIME_PIPELINE_H_
+
+#include <memory>
+#include <vector>
+
+#include "Firestore/core/src/api/pipeline_snapshot.h"
+#include "Firestore/core/src/api/stages.h"
+#include "Firestore/core/src/remote/serializer.h"
+
+namespace firebase {
+namespace firestore {
+namespace api {
+
+class RealtimePipeline {
+ public:
+  RealtimePipeline(std::vector<std::shared_ptr<EvaluableStage>> stages,
+                   remote::Serializer serializer);
+
+  RealtimePipeline AddingStage(std::shared_ptr<EvaluableStage> stage);
+
+  const std::vector<std::shared_ptr<EvaluableStage>>& stages() const;
+
+  EvaluateContext evaluate_context();
+
+ private:
+  std::vector<std::shared_ptr<EvaluableStage>> stages_;
+  remote::Serializer serializer_;
+};
+
+}  // namespace api
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_API_REALTIME_PIPELINE_H_

Firestore/core/src/api/realtime_pipeline.h

@@ -16,13 +16,26 @@
 
 #include "Firestore/core/src/api/stages.h"
 
+#include <algorithm>
+#include <memory>
+#include <stdexcept>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
+#include <vector>
 
 #include "Firestore/Protos/nanopb/google/firestore/v1/document.nanopb.h"
 #include "Firestore/core/src/api/pipeline.h"
+#include "Firestore/core/src/core/expressions_eval.h"
+#include "Firestore/core/src/model/document.h"
+#include "Firestore/core/src/model/document_key.h"
+#include "Firestore/core/src/model/mutable_document.h"
+#include "Firestore/core/src/model/resource_path.h"
+#include "Firestore/core/src/model/value_util.h"
 #include "Firestore/core/src/nanopb/message.h"
 #include "Firestore/core/src/nanopb/nanopb_util.h"
+#include "Firestore/core/src/util/comparison.h"
+#include "Firestore/core/src/util/hard_assert.h"
 
 namespace firebase {
 namespace firestore {
@@ -461,6 +474,62 @@ google_firestore_v1_Pipeline_Stage RawStage::to_proto() const {
   return result;
 }
 
+model::PipelineInputOutputVector CollectionSource::Evaluate(
+    const EvaluateContext& /*context*/,
+    const model::PipelineInputOutputVector& inputs) const {
+  model::PipelineInputOutputVector results;
+  std::copy_if(inputs.begin(), inputs.end(), std::back_inserter(results),
+               [this](const model::MutableDocument& doc) {
+                 return doc.is_found_document() &&
+                        doc.key().path().PopLast().CanonicalString() == path_;
+               });
+  return results;
+}
+
+model::PipelineInputOutputVector DatabaseSource::Evaluate(
+    const EvaluateContext& /*context*/,
+    const model::PipelineInputOutputVector& inputs) const {
+  model::PipelineInputOutputVector results;
+  std::copy_if(inputs.begin(), inputs.end(), std::back_inserter(results),
+               [](const model::MutableDocument& doc) {
+                 return doc.is_found_document();
+               });
+  return results;
+}
+
+model::PipelineInputOutputVector Where::Evaluate(
+    const EvaluateContext& context,
+    const model::PipelineInputOutputVector& inputs) const {
+  model::PipelineInputOutputVector results;
+  const auto evaluable_expr = expr_->ToEvaluable();
+  const auto true_value = model::TrueValue();
+
+  for (const auto& doc : inputs) {
+    auto result = evaluable_expr->Evaluate(context, doc);
+    if (!result.IsErrorOrUnset() &&
+        model::Equals(*result.value(), true_value)) {
+      results.push_back(doc);
+    }
+  }
+
+  return results;
+}
+
+model::PipelineInputOutputVector LimitStage::Evaluate(
+    const EvaluateContext& /*context*/,
+    const model::PipelineInputOutputVector& inputs) const {
+  if (limit_ < 0) {
+    // Or handle as error? Assuming non-negative limit.
+    return {};
+  }
+  size_t count = static_cast<size_t>(limit_);
+  if (count > inputs.size()) {
+    count = inputs.size();
+  }
+  return model::PipelineInputOutputVector(inputs.begin(),
+                                          inputs.begin() + count);
+}
+
 }  // namespace api
 }  // namespace firestore
 }  // namespace firebase