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1 /*
2  * Copyright (C) 2023 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef SRC_TRACE_PROCESSOR_PERFETTO_SQL_PARSER_PERFETTO_SQL_PARSER_H_
18 #define SRC_TRACE_PROCESSOR_PERFETTO_SQL_PARSER_PERFETTO_SQL_PARSER_H_
19 
20 #include <memory>
21 #include <optional>
22 #include <string>
23 #include <utility>
24 #include <variant>
25 #include <vector>
26 
27 #include "perfetto/base/logging.h"
28 #include "perfetto/ext/base/flat_hash_map.h"
29 #include "src/trace_processor/perfetto_sql/grammar/perfettosql_grammar_interface.h"
30 #include "src/trace_processor/perfetto_sql/parser/function_util.h"
31 #include "src/trace_processor/perfetto_sql/preprocessor/perfetto_sql_preprocessor.h"
32 #include "src/trace_processor/sqlite/sql_source.h"
33 #include "src/trace_processor/util/sql_argument.h"
34 
35 namespace perfetto::trace_processor {
36 
37 // Parser for PerfettoSQL statements. This class provides an iterator-style
38 // interface for reading all PerfettoSQL statements from a block of SQL.
39 //
40 // Usage:
41 // PerfettoSqlParser parser(my_sql_string.c_str());
42 // while (parser.Next()) {
43 //   auto& stmt = parser.statement();
44 //   // Handle |stmt| here
45 // }
46 // RETURN_IF_ERROR(r.status());
47 class PerfettoSqlParser {
48  public:
49   // Indicates that the specified SQLite SQL was extracted directly from a
50   // PerfettoSQL statement and should be directly executed with SQLite.
51   struct SqliteSql {};
52   // Indicates that the specified SQL was a CREATE PERFETTO FUNCTION statement
53   // with the following parameters.
54   struct CreateFunction {
55     struct Returns {
56       bool is_table;
57       // Only set when `is_table` is false.
58       sql_argument::Type scalar_type;
59       // Only set when `is_table` is true.
60       std::vector<sql_argument::ArgumentDefinition> table_columns;
61     };
62     bool replace;
63     FunctionPrototype prototype;
64     Returns returns;
65     SqlSource sql;
66     std::string description;
67   };
68   // Indicates that the specified SQL was a CREATE PERFETTO TABLE statement
69   // with the following parameters.
70   struct CreateTable {
71     bool replace;
72     std::string name;
73     std::vector<sql_argument::ArgumentDefinition> schema;
74     // SQL source for the select statement.
75     SqlSource sql;
76   };
77   // Indicates that the specified SQL was a CREATE PERFETTO VIEW statement
78   // with the following parameters.
79   struct CreateView {
80     bool replace;
81     std::string name;
82     std::vector<sql_argument::ArgumentDefinition> schema;
83     // SQL source for the select statement.
84     SqlSource sql;
85     // SQL source for the CREATE VIEW statement.
86     SqlSource create_view_sql;
87   };
88   // Indicates that the specified SQL was a CREATE PERFETTO INDEX statement
89   // with the following parameters.
90   struct CreateIndex {
91     bool replace;
92     std::string name;
93     std::string table_name;
94     std::vector<std::string> col_names;
95   };
96   // Indicates that the specified SQL was a DROP PERFETTO INDEX statement
97   // with the following parameters.
98   struct DropIndex {
99     std::string name;
100     std::string table_name;
101   };
102   // Indicates that the specified SQL was a INCLUDE PERFETTO MODULE statement
103   // with the following parameter.
104   struct Include {
105     std::string key;
106   };
107   // Indicates that the specified SQL was a CREATE PERFETTO MACRO statement
108   // with the following parameter.
109   struct CreateMacro {
110     bool replace;
111     SqlSource name;
112     std::vector<std::pair<SqlSource, SqlSource>> args;
113     SqlSource returns;
114     SqlSource sql;
115   };
116 
117   using Statement = std::variant<CreateFunction,
118                                  CreateIndex,
119                                  CreateMacro,
120                                  CreateTable,
121                                  CreateView,
122                                  DropIndex,
123                                  Include,
124                                  SqliteSql>;
125 
126   // Creates a new SQL parser with the a block of PerfettoSQL statements.
127   // Concretely, the passed string can contain >1 statement.
128   explicit PerfettoSqlParser(
129       SqlSource,
130       const base::FlatHashMap<std::string, PerfettoSqlPreprocessor::Macro>&);
131 
132   ~PerfettoSqlParser();
133 
134   PerfettoSqlParser(const PerfettoSqlParser&) = delete;
135   PerfettoSqlParser& operator=(const PerfettoSqlParser&) = delete;
136 
137   PerfettoSqlParser(PerfettoSqlParser&&) = delete;
138   PerfettoSqlParser& operator=(PerfettoSqlParser&&) = delete;
139 
140   // Attempts to parse to the next statement in the SQL. Returns true if
141   // a statement was successfully parsed and false if EOF was reached or the
142   // statement was not parsed correctly.
143   //
144   // Note: if this function returns false, callers *must* call |status()|: it
145   // is undefined behaviour to not do so.
146   bool Next();
147 
148   // Returns the current statement which was parsed. This function *must not* be
149   // called unless |Next()| returned true.
150   const Statement& statement() const;
151 
152   // Returns the full statement which was parsed. This should return
153   // |statement()| and Perfetto SQL code that's in front. This function *must
154   // not* be called unless |Next()| returned true.
statement_sql()155   const SqlSource& statement_sql() const {
156     PERFETTO_CHECK(statement_sql_);
157     return *statement_sql_;
158   }
159 
160   // Returns the error status for the parser. This will be |base::OkStatus()|
161   // until an unrecoverable error is encountered.
162   const base::Status& status() const;
163 
164  private:
165   std::unique_ptr<PerfettoSqlParserState> parser_state_;
166   std::optional<SqlSource> statement_sql_;
167 };
168 
169 }  // namespace perfetto::trace_processor
170 
171 #endif  // SRC_TRACE_PROCESSOR_PERFETTO_SQL_PARSER_PERFETTO_SQL_PARSER_H_
172