1 files changed, 168 insertions, 0 deletions
diff --git a/ext/expert/sqlite3expert.h b/ext/expert/sqlite3expert.h
new file mode 100644
index 0000000..6048137
--- /dev/null
+++ b/ext/expert/sqlite3expert.h
@@ -0,0 +1,168 @@
+/*
+** 2017 April 07
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+#if !defined(SQLITEEXPERT_H)
+#define SQLITEEXPERT_H 1
+#include "sqlite3.h"
+
+typedef struct sqlite3expert sqlite3expert;
+
+/*
+** Create a new sqlite3expert object.
+**
+** If successful, a pointer to the new object is returned and (*pzErr) set
+** to NULL. Or, if an error occurs, NULL is returned and (*pzErr) set to
+** an English-language error message. In this case it is the responsibility
+** of the caller to eventually free the error message buffer using
+** sqlite3_free().
+*/
+sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErr);
+
+/*
+** Configure an sqlite3expert object.
+**
+** EXPERT_CONFIG_SAMPLE:
+**   By default, sqlite3_expert_analyze() generates sqlite_stat1 data for
+**   each candidate index. This involves scanning and sorting the entire
+**   contents of each user database table once for each candidate index
+**   associated with the table. For large databases, this can be 
+**   prohibitively slow. This option allows the sqlite3expert object to
+**   be configured so that sqlite_stat1 data is instead generated based on a
+**   subset of each table, or so that no sqlite_stat1 data is used at all.
+**
+**   A single integer argument is passed to this option. If the value is less
+**   than or equal to zero, then no sqlite_stat1 data is generated or used by
+**   the analysis - indexes are recommended based on the database schema only.
+**   Or, if the value is 100 or greater, complete sqlite_stat1 data is
+**   generated for each candidate index (this is the default). Finally, if the
+**   value falls between 0 and 100, then it represents the percentage of user
+**   table rows that should be considered when generating sqlite_stat1 data.
+**
+**   Examples:
+**
+**     // Do not generate any sqlite_stat1 data
+**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 0);
+**
+**     // Generate sqlite_stat1 data based on 10% of the rows in each table.
+**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 10);
+*/
+int sqlite3_expert_config(sqlite3expert *p, int op, ...);
+
+#define EXPERT_CONFIG_SAMPLE 1    /* int */
+
+/*
+** Specify zero or more SQL statements to be included in the analysis.
+**
+** Buffer zSql must contain zero or more complete SQL statements. This
+** function parses all statements contained in the buffer and adds them
+** to the internal list of statements to analyze. If successful, SQLITE_OK
+** is returned and (*pzErr) set to NULL. Or, if an error occurs - for example
+** due to a error in the SQL - an SQLite error code is returned and (*pzErr)
+** may be set to point to an English language error message. In this case
+** the caller is responsible for eventually freeing the error message buffer
+** using sqlite3_free().
+**
+** If an error does occur while processing one of the statements in the
+** buffer passed as the second argument, none of the statements in the
+** buffer are added to the analysis.
+**
+** This function must be called before sqlite3_expert_analyze(). If a call
+** to this function is made on an sqlite3expert object that has already
+** been passed to sqlite3_expert_analyze() SQLITE_MISUSE is returned
+** immediately and no statements are added to the analysis.
+*/
+int sqlite3_expert_sql(
+  sqlite3expert *p,               /* From a successful sqlite3_expert_new() */
+  const char *zSql,               /* SQL statement(s) to add */
+  char **pzErr                    /* OUT: Error message (if any) */
+);
+
+
+/*
+** This function is called after the sqlite3expert object has been configured
+** with all SQL statements using sqlite3_expert_sql() to actually perform
+** the analysis. Once this function has been called, it is not possible to
+** add further SQL statements to the analysis.
+**
+** If successful, SQLITE_OK is returned and (*pzErr) is set to NULL. Or, if
+** an error occurs, an SQLite error code is returned and (*pzErr) set to 
+** point to a buffer containing an English language error message. In this
+** case it is the responsibility of the caller to eventually free the buffer
+** using sqlite3_free().
+**
+** If an error does occur within this function, the sqlite3expert object
+** is no longer useful for any purpose. At that point it is no longer
+** possible to add further SQL statements to the object or to re-attempt
+** the analysis. The sqlite3expert object must still be freed using a call
+** sqlite3_expert_destroy().
+*/
+int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr);
+
+/*
+** Return the total number of statements loaded using sqlite3_expert_sql().
+** The total number of SQL statements may be different from the total number
+** to calls to sqlite3_expert_sql().
+*/
+int sqlite3_expert_count(sqlite3expert*);
+
+/*
+** Return a component of the report.
+**
+** This function is called after sqlite3_expert_analyze() to extract the
+** results of the analysis. Each call to this function returns either a
+** NULL pointer or a pointer to a buffer containing a nul-terminated string.
+** The value passed as the third argument must be one of the EXPERT_REPORT_*
+** #define constants defined below.
+**
+** For some EXPERT_REPORT_* parameters, the buffer returned contains 
+** information relating to a specific SQL statement. In these cases that
+** SQL statement is identified by the value passed as the second argument.
+** SQL statements are numbered from 0 in the order in which they are parsed.
+** If an out-of-range value (less than zero or equal to or greater than the
+** value returned by sqlite3_expert_count()) is passed as the second argument
+** along with such an EXPERT_REPORT_* parameter, NULL is always returned.
+**
+** EXPERT_REPORT_SQL:
+**   Return the text of SQL statement iStmt.
+**
+** EXPERT_REPORT_INDEXES:
+**   Return a buffer containing the CREATE INDEX statements for all recommended
+**   indexes for statement iStmt. If there are no new recommeded indexes, NULL 
+**   is returned.
+**
+** EXPERT_REPORT_PLAN:
+**   Return a buffer containing the EXPLAIN QUERY PLAN output for SQL query
+**   iStmt after the proposed indexes have been added to the database schema.
+**
+** EXPERT_REPORT_CANDIDATES:
+**   Return a pointer to a buffer containing the CREATE INDEX statements 
+**   for all indexes that were tested (for all SQL statements). The iStmt
+**   parameter is ignored for EXPERT_REPORT_CANDIDATES calls.
+*/
+const char *sqlite3_expert_report(sqlite3expert*, int iStmt, int eReport);
+
+/*
+** Values for the third argument passed to sqlite3_expert_report().
+*/
+#define EXPERT_REPORT_SQL        1
+#define EXPERT_REPORT_INDEXES    2
+#define EXPERT_REPORT_PLAN       3
+#define EXPERT_REPORT_CANDIDATES 4
+
+/*
+** Free an (sqlite3expert*) handle and all associated resources. There 
+** should be one call to this function for each successful call to 
+** sqlite3-expert_new().
+*/
+void sqlite3_expert_destroy(sqlite3expert*);
+
+#endif  /* !defined(SQLITEEXPERT_H) */