Refactor code to suggest indexes from the shell tool into an extension in

ext/expert. Unfinished.

FossilOrigin-Name: 305e19f976ca064638a294e0817bf547ea745e1eb74746c5855514e6ced9c5fa

ext/expert/expert.c

@@ -0,0 +1,104 @@
+/*
+** 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.
+**
+*************************************************************************
+*/
+
+
+#include <sqlite3.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "sqlite3expert.h"
+
+
+static void option_requires_argument(const char *zOpt){
+  fprintf(stderr, "Option requires an argument: %s\n", zOpt);
+  exit(-3);
+}
+
+static void usage(char **argv){
+  fprintf(stderr, "\n");
+  fprintf(stderr, "Usage %s ?OPTIONS? DATABASE\n", argv[0]);
+  fprintf(stderr, "\n");
+  fprintf(stderr, "Options are:\n");
+  fprintf(stderr, "  -sql SQL   (analyze SQL statements passed as argument)\n");
+  fprintf(stderr, "  -file FILE (read SQL statements from file FILE)\n");
+  exit(-1);
+}
+
+static int readSqlFromFile(sqlite3expert *p, const char *zFile, char **pzErr){
+  return SQLITE_OK;
+}
+
+int main(int argc, char **argv){
+  const char *zDb;
+  int rc = 0;
+  char *zErr = 0;
+  int i;
+
+  sqlite3 *db = 0;
+  sqlite3expert *p = 0;
+
+  if( argc<2 ) usage(argv);
+  zDb = argv[argc-1];
+  rc = sqlite3_open(zDb, &db);
+  if( rc!=SQLITE_OK ){
+    fprintf(stderr, "Cannot open db file: %s - %s\n", zDb, sqlite3_errmsg(db));
+    exit(-2);
+  }
+
+  p = sqlite3_expert_new(db, &zErr);
+  if( p==0 ){
+    fprintf(stderr, "Cannot run analysis: %s\n", zErr);
+    rc = 1;
+  }else{
+    for(i=1; i<(argc-1); i++){
+      char *zArg = argv[i];
+      int nArg = strlen(zArg);
+      if( nArg>=2 && 0==sqlite3_strnicmp(zArg, "-file", nArg) ){
+        if( ++i==(argc-1) ) option_requires_argument("-file");
+        rc = readSqlFromFile(p, argv[i], &zErr);
+      }
+
+      else if( nArg>=2 && 0==sqlite3_strnicmp(zArg, "-sql", nArg) ){
+        if( ++i==(argc-1) ) option_requires_argument("-sql");
+        rc = sqlite3_expert_sql(p, argv[i], &zErr);
+      }
+
+      else{
+        usage(argv);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_expert_analyze(p, &zErr);
+  }
+
+  if( rc==SQLITE_OK ){
+    int nQuery = sqlite3_expert_count(p);
+    for(i=0; i<nQuery; i++){
+      const char *zSql = sqlite3_expert_report(p, i, EXPERT_REPORT_SQL);
+      const char *zIdx = sqlite3_expert_report(p, i, EXPERT_REPORT_INDEXES);
+      const char *zEQP = sqlite3_expert_report(p, i, EXPERT_REPORT_PLAN);
+      fprintf(stdout, "-- query %d ----------------------------------\n", i+1);
+      fprintf(stdout, "%s\n\n%s\n%s\n", zSql, zIdx, zEQP);
+    }
+  }else if( zErr ){
+    fprintf(stderr, "Error: %s\n", zErr);
+  }
+
+  sqlite3_expert_destroy(p);
+  sqlite3_free(zErr);
+  return rc;
+}
+
+

ext/expert/sqlite3expert.h

@@ -0,0 +1,57 @@
+/*
+** 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.
+**
+*************************************************************************
+*/
+
+
+#include "sqlite3.h"
+
+typedef struct sqlite3expert sqlite3expert;
+
+/*
+** Create a new sqlite3expert object.
+*/
+sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErr);
+
+/*
+** Add an SQL statement to the analysis.
+*/
+int sqlite3_expert_sql(
+  sqlite3expert *p,               /* From sqlite3_expert_new() */
+  const char *zSql,               /* SQL statement to add */
+  char **pzErr                    /* OUT: Error message (if any) */
+);
+
+int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr);
+
+/*
+** Return the total number of SQL queries loaded via sqlite3_expert_sql().
+*/
+int sqlite3_expert_count(sqlite3expert*);
+
+/*
+** Return a component of the report.
+*/
+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
+
+/*
+** Free an (sqlite3expert*) handle allocated by sqlite3-expert_new().
+*/
+void sqlite3_expert_destroy(sqlite3expert*);
+
+