feat:add init expression interface.

src/iceberg/CMakeLists.txt

@@ -34,6 +34,8 @@ set(ICEBERG_SOURCES
     transform.cc
     transform_function.cc
     type.cc
+    snapshot.cc
+    expression.cc
     util/murmurhash3_internal.cc)
 
 set(ICEBERG_STATIC_BUILD_INTERFACE_LIBS)

src/iceberg/expression.cc

@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 "expression.h"
+
+#include <format>
+
+namespace iceberg {
+
+// True implementation
+const std::shared_ptr<True>& True::Instance() {
+  static const std::shared_ptr<True> instance{new True()};
+  return instance;
+}
+
+Result<std::shared_ptr<Expression>> True::Negate() const { return False::Instance(); }
+
+// False implementation
+const std::shared_ptr<False>& False::Instance() {
+  static const std::shared_ptr<False> instance = std::shared_ptr<False>(new False());
+  return instance;
+}
+
+Result<std::shared_ptr<Expression>> False::Negate() const { return True::Instance(); }
+
+// And implementation
+And::And(std::shared_ptr<Expression> left, std::shared_ptr<Expression> right)
+    : left_(std::move(left)), right_(std::move(right)) {}
+
+std::string And::ToString() const {
+  return std::format("({} and {})", left_->ToString(), right_->ToString());
+}
+
+Result<std::shared_ptr<Expression>> And::Negate() const {
+  // TODO(yingcai-cy): Implement Or expression
+  return unexpected(
+      Error(ErrorKind::kInvalidExpression, "And negation not yet implemented"));
+}
+
+bool And::Equals(const Expression& expr) const {
+  if (expr.op() == Operation::kAnd) {
+    const auto& other = static_cast<const And&>(expr);
+    return (left_->Equals(*other.left()) && right_->Equals(*other.right())) ||
+           (left_->Equals(*other.right()) && right_->Equals(*other.left()));
+  }
+  return false;
+}
+
+}  // namespace iceberg

src/iceberg/expression.h

@@ -0,0 +1,163 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+#pragma once
+
+/// \file iceberg/expression.h
+/// Expression interface for Iceberg table operations.
+
+#include <memory>
+#include <string>
+
+#include "iceberg/expected.h"
+#include "iceberg/iceberg_export.h"
+#include "iceberg/result.h"
+
+namespace iceberg {
+
+/// \brief Represents a boolean expression tree.
+class ICEBERG_EXPORT Expression {
+ public:
+  /// Operation types for expressions
+  enum class Operation {
+    kTrue,
+    kFalse,
+    kIsNull,
+    kNotNull,
+    kIsNan,
+    kNotNan,
+    kLt,
+    kLtEq,
+    kGt,
+    kGtEq,
+    kEq,
+    kNotEq,
+    kIn,
+    kNotIn,
+    kNot,
+    kAnd,
+    kOr,
+    kStartsWith,
+    kNotStartsWith,
+    kCount,
+    kCountStar,
+    kMax,
+    kMin
+  };
+
+  virtual ~Expression() = default;
+
+  /// \brief Returns the operation for an expression node.
+  virtual Operation op() const = 0;
+
+  /// \brief Returns the negation of this expression, equivalent to not(this).
+  virtual Result<std::shared_ptr<Expression>> Negate() const {
+    return unexpected(
+        Error(ErrorKind::kInvalidExpression, "Expression cannot be negated"));
+  }
+
+  /// \brief Returns whether this expression will accept the same values as another.
+  /// \param other another expression
+  /// \return true if the expressions are equivalent
+  virtual bool Equals(const Expression& other) const {
+    // only bound predicates can be equivalent
+    return false;
+  }
+
+  virtual std::string ToString() const { return "Expression"; }
+};
+
+/// \brief An Expression that is always true.
+///
+/// Represents a boolean predicate that always evaluates to true.
+class ICEBERG_EXPORT True : public Expression {
+ public:
+  /// \brief Returns the singleton instance
+  static const std::shared_ptr<True>& Instance();
+
+  Operation op() const override { return Operation::kTrue; }
+
+  std::string ToString() const override { return "true"; }
+
+  Result<std::shared_ptr<Expression>> Negate() const override;
+
+  bool Equals(const Expression& other) const override {
+    return other.op() == Operation::kTrue;
+  }
+
+ private:
+  constexpr True() = default;
+};
+
+/// \brief An expression that is always false.
+class ICEBERG_EXPORT False : public Expression {
+ public:
+  /// \brief Returns the singleton instance
+  static const std::shared_ptr<False>& Instance();
+
+  Operation op() const override { return Operation::kFalse; }
+
+  std::string ToString() const override { return "false"; }
+
+  Result<std::shared_ptr<Expression>> Negate() const override;
+
+  bool Equals(const Expression& other) const override {
+    return other.op() == Operation::kFalse;
+  }
+
+ private:
+  constexpr False() = default;
+};
+
+/// \brief An Expression that represents a logical AND operation between two expressions.
+///
+/// This expression evaluates to true if and only if both of its child expressions
+/// evaluate to true.
+class ICEBERG_EXPORT And : public Expression {
+ public:
+  /// \brief Constructs an And expression from two sub-expressions.
+  ///
+  /// \param left The left operand of the AND expression
+  /// \param right The right operand of the AND expression
+  And(std::shared_ptr<Expression> left, std::shared_ptr<Expression> right);
+
+  /// \brief Returns the left operand of the AND expression.
+  ///
+  /// \return The left operand of the AND expression
+  const std::shared_ptr<Expression>& left() const { return left_; }
+
+  /// \brief Returns the right operand of the AND expression.
+  ///
+  /// \return The right operand of the AND expression
+  const std::shared_ptr<Expression>& right() const { return right_; }
+
+  Operation op() const override { return Operation::kAnd; }
+
+  std::string ToString() const override;
+
+  Result<std::shared_ptr<Expression>> Negate() const override;
+
+  bool Equals(const Expression& other) const override;
+
+ private:
+  std::shared_ptr<Expression> left_;
+  std::shared_ptr<Expression> right_;
+};
+
+}  // namespace iceberg

src/iceberg/result.h

@@ -39,6 +39,7 @@ enum class ErrorKind {
   kNotImplemented,
   kUnknownError,
   kNotSupported,
+  kInvalidExpression,
   kJsonParseError,
 };
 

test/CMakeLists.txt

@@ -44,6 +44,12 @@ target_sources(expected_test PRIVATE expected_test.cc)
 target_link_libraries(expected_test PRIVATE iceberg_static GTest::gtest_main GTest::gmock)
 add_test(NAME expected_test COMMAND expected_test)
 
+add_executable(expression_test)
+target_sources(expression_test PRIVATE expression_test.cc)
+target_link_libraries(expression_test PRIVATE iceberg_static GTest::gtest_main
+                                              GTest::gmock)
+add_test(NAME expression_test COMMAND expression_test)
+
 if(ICEBERG_BUILD_BUNDLE)
   add_executable(avro_test)
   target_sources(avro_test PRIVATE avro_test.cc)

test/expression_test.cc

@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 "iceberg/expression.h"
+
+#include <memory>
+
+#include <gtest/gtest.h>
+
+namespace iceberg {
+
+TEST(TrueFalseTest, Basic) {
+  // Test negation of False returns True
+  auto false_instance = False::Instance();
+  auto negated = false_instance->Negate();
+
+  EXPECT_TRUE(negated.has_value());
+
+  // Check that negated expression is True
+  auto true_expr = negated.value();
+  EXPECT_EQ(true_expr->op(), Expression::Operation::kTrue);
+
+  EXPECT_EQ(true_expr->ToString(), "true");
+
+  // Test negation of True returns false
+  auto true_instance = True::Instance();
+  negated = true_instance->Negate();
+
+  EXPECT_TRUE(negated.has_value());
+
+  // Check that negated expression is False
+  auto false_expr = negated.value();
+  EXPECT_EQ(false_expr->op(), Expression::Operation::kFalse);
+
+  EXPECT_EQ(false_expr->ToString(), "false");
+}
+
+TEST(ANDTest, Basic) {
+  // Create two True expressions
+  auto true_expr1 = True::Instance();
+  auto true_expr2 = True::Instance();
+
+  // Create an AND expression
+  auto and_expr = std::make_shared<And>(true_expr1, true_expr2);
+
+  EXPECT_EQ(and_expr->op(), Expression::Operation::kAnd);
+  EXPECT_EQ(and_expr->ToString(), "(true and true)");
+  EXPECT_EQ(and_expr->left()->op(), Expression::Operation::kTrue);
+  EXPECT_EQ(and_expr->right()->op(), Expression::Operation::kTrue);
+}
+}  // namespace iceberg