Fix for LittleFS and add example

Author: siara-cc

examples/sqlite3_littlefs/sqlite3_littlefs.ino

@@ -0,0 +1,147 @@
+/*
+    This creates two empty databases, populates values, and retrieves them back
+    from the LITTLEFS file system
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <sqlite3.h>
+#include <SPI.h>
+#include <FS.h>
+#include "LittleFS.h"
+
+/* You only need to format LITTLEFS the first time you run a
+   test or else use the LITTLEFS plugin to create a partition
+   https://github.com/lorol/arduino-esp32fs-plugin/releases */
+#define FORMAT_LITTLEFS_IF_FAILED true
+
+const char* data = "Callback function called";
+static int callback(void *data, int argc, char **argv, char **azColName) {
+   int i;
+   Serial.printf("%s: ", (const char*)data);
+   for (i = 0; i<argc; i++){
+       Serial.printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
+   }
+   Serial.printf("\n");
+   return 0;
+}
+
+int db_open(const char *filename, sqlite3 **db) {
+   int rc = sqlite3_open(filename, db);
+   if (rc) {
+       Serial.printf("Can't open database: %s\n", sqlite3_errmsg(*db));
+       return rc;
+   } else {
+       Serial.printf("Opened database successfully\n");
+   }
+   return rc;
+}
+
+char *zErrMsg = 0;
+int db_exec(sqlite3 *db, const char *sql) {
+   Serial.println(sql);
+   long start = micros();
+   int rc = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
+   if (rc != SQLITE_OK) {
+       Serial.printf("SQL error: %s\n", zErrMsg);
+       sqlite3_free(zErrMsg);
+   } else {
+       Serial.printf("Operation done successfully\n");
+   }
+   Serial.print(F("Time taken:"));
+   Serial.println(micros()-start);
+   return rc;
+}
+
+void setup() {
+
+   Serial.begin(115200);
+   sqlite3 *db1;
+   sqlite3 *db2;
+   int rc;
+
+   if (!LittleFS.begin(FORMAT_LITTLEFS_IF_FAILED, "/littlefs")) {
+       Serial.println("Failed to mount file system");
+       return;
+   }
+
+   // list LITTLEFS contents
+   File root = LittleFS.open("/");
+   if (!root) {
+       Serial.println("- failed to open directory");
+       return;
+   }
+   if (!root.isDirectory()) {
+       Serial.println(" - not a directory");
+       return;
+   }
+   File file = root.openNextFile();
+   while (file) {
+       if (file.isDirectory()) {
+           Serial.print("  DIR : ");
+           Serial.println(file.name());
+       } else {
+           Serial.print("  FILE: ");
+           Serial.print(file.name());
+           Serial.print("\tSIZE: ");
+           Serial.println(file.size());
+       }
+       file = root.openNextFile();
+   }
+
+   // remove existing file
+   LittleFS.remove("/test1.db");
+   LittleFS.remove("/test2.db");
+
+   sqlite3_initialize();
+
+   if (db_open("/littlefs/test1.db", &db1))
+       return;
+   if (db_open("/littlefs/test2.db", &db2))
+       return;
+
+   rc = db_exec(db1, "CREATE TABLE test1 (id INTEGER, content);");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+   rc = db_exec(db2, "CREATE TABLE test2 (id INTEGER, content);");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+
+   rc = db_exec(db1, "INSERT INTO test1 VALUES (1, 'Hello, World from test1');");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+   rc = db_exec(db2, "INSERT INTO test2 VALUES (1, 'Hello, World from test2');");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+
+   rc = db_exec(db1, "SELECT * FROM test1");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+   rc = db_exec(db2, "SELECT * FROM test2");
+   if (rc != SQLITE_OK) {
+       sqlite3_close(db1);
+       sqlite3_close(db2);
+       return;
+   }
+
+   sqlite3_close(db1);
+   sqlite3_close(db2);
+
+}
+
+void loop() {
+}

src/esp32.cpp

@@ -300,7 +300,7 @@ static int ESP32FileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
 
 	struct stat st;
 	int fno = fileno(p->fp);
-	if (fno == -1)
+	if (fno < 0)
 		return SQLITE_IOERR_FSTAT;
 	if (fstat(fno, &st))
 		return SQLITE_IOERR_FSTAT;
@@ -433,7 +433,7 @@ static int ESP32Open(
     memset(&st, 0, sizeof(struct stat));
     int rc = stat( zName, &st );
     //Serial.println(zName);
-		if (rc == -1) {
+		if (rc < 0) {
       strcpy(mode, "w+");
       //int fd = open(zName, (O_CREAT | O_RDWR | O_EXCL), S_IRUSR | S_IWUSR);
       //close(fd);