Add support for _not_ creating a DB if one does not exist

taskchampion/integration-tests/src/bindings_tests/replica.c

@@ -14,7 +14,7 @@ static void test_replica_creation(void) {
 
 // creating an on-disk replica does not crash
 static void test_replica_creation_disk(void) {
-    TCReplica *rep = tc_replica_new_on_disk(tc_string_borrow("test-db"), NULL);
+    TCReplica *rep = tc_replica_new_on_disk(tc_string_borrow("test-db"), true, NULL);
     TEST_ASSERT_NOT_NULL(rep);
     TEST_ASSERT_NULL(tc_replica_error(rep).ptr);
     tc_replica_free(rep);

taskchampion/lib/src/replica.rs

@@ -140,6 +140,7 @@ pub unsafe extern "C" fn tc_replica_new_in_memory() -> *mut TCReplica {
 #[no_mangle]
 pub unsafe extern "C" fn tc_replica_new_on_disk(
     path: TCString,
+    create_if_missing: bool,
     error_out: *mut TCString,
 ) -> *mut TCReplica {
     wrap_constructor(
@@ -150,6 +151,7 @@ pub unsafe extern "C" fn tc_replica_new_on_disk(
             let mut path = unsafe { TCString::val_from_arg(path) };
             let storage = StorageConfig::OnDisk {
                 taskdb_dir: path.to_path_buf_mut()?,
+                create_if_missing,
             }
             .into_storage()?;
 

taskchampion/lib/taskchampion.h

@@ -492,7 +492,9 @@ struct TCReplica *tc_replica_new_in_memory(void);
  * is written to the error_out parameter (if it is not NULL) and NULL is returned.  The caller
  * must free this string.
  */
-struct TCReplica *tc_replica_new_on_disk(struct TCString path, struct TCString *error_out);
+struct TCReplica *tc_replica_new_on_disk(struct TCString path,
+                                         bool create_if_missing,
+                                         struct TCString *error_out);
 
 /**
  * Get a list of all tasks in the replica.

taskchampion/taskchampion/src/storage/config.rs

@@ -7,6 +7,9 @@ pub enum StorageConfig {
     OnDisk {
         /// Path containing the task DB.
         taskdb_dir: PathBuf,
+
+        /// Create the DB if it does not already exist
+        create_if_missing: bool,
     },
     /// Store the data in memory.  This is only useful for testing.
     InMemory,
@@ -15,7 +18,10 @@ pub enum StorageConfig {
 impl StorageConfig {
     pub fn into_storage(self) -> anyhow::Result<Box<dyn Storage>> {
         Ok(match self {
-            StorageConfig::OnDisk { taskdb_dir } => Box::new(SqliteStorage::new(taskdb_dir)?),
+            StorageConfig::OnDisk {
+                taskdb_dir,
+                create_if_missing,
+            } => Box::new(SqliteStorage::new(taskdb_dir, create_if_missing)?),
             StorageConfig::InMemory => Box::new(InMemoryStorage::new()),
         })
     }

taskchampion/taskchampion/src/storage/sqlite.rs

@@ -1,7 +1,7 @@
 use crate::storage::{ReplicaOp, Storage, StorageTxn, TaskMap, VersionId, DEFAULT_BASE_VERSION};
 use anyhow::Context;
 use rusqlite::types::{FromSql, ToSql};
-use rusqlite::{params, Connection, OptionalExtension};
+use rusqlite::{params, Connection, OpenFlags, OptionalExtension};
 use std::path::Path;
 use uuid::Uuid;
 
@@ -76,13 +76,24 @@ pub struct SqliteStorage {
 }
 
 impl SqliteStorage {
-    pub fn new<P: AsRef<Path>>(directory: P) -> anyhow::Result<SqliteStorage> {
+    pub fn new<P: AsRef<Path>>(
+        directory: P,
+        create_if_missing: bool,
+    ) -> anyhow::Result<SqliteStorage> {
+        if create_if_missing {
             // Ensure parent folder exists
             std::fs::create_dir_all(&directory)?;
+        }
 
         // Open (or create) database
         let db_file = directory.as_ref().join("taskchampion.sqlite3");
-        let con = Connection::open(db_file)?;
+        let mut flags = OpenFlags::SQLITE_OPEN_READ_WRITE
+            | OpenFlags::SQLITE_OPEN_NO_MUTEX
+            | OpenFlags::SQLITE_OPEN_URI;
+        if create_if_missing {
+            flags |= OpenFlags::SQLITE_OPEN_CREATE;
+        }
+        let con = Connection::open_with_flags(db_file, flags)?;
 
         // Initialize database
         let queries = vec![
@@ -369,7 +380,7 @@ mod test {
     fn test_empty_dir() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
         let non_existant = tmp_dir.path().join("subdir");
-        let mut storage = SqliteStorage::new(&non_existant)?;
+        let mut storage = SqliteStorage::new(&non_existant, true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -387,7 +398,7 @@ mod test {
     #[test]
     fn drop_transaction() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();
 
@@ -416,7 +427,7 @@ mod test {
     #[test]
     fn test_create() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -434,7 +445,7 @@ mod test {
     #[test]
     fn test_create_exists() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -452,7 +463,7 @@ mod test {
     #[test]
     fn test_get_missing() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -465,7 +476,7 @@ mod test {
     #[test]
     fn test_set_task() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -486,7 +497,7 @@ mod test {
     #[test]
     fn test_delete_task_missing() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -498,7 +509,7 @@ mod test {
     #[test]
     fn test_delete_task_exists() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -515,7 +526,7 @@ mod test {
     #[test]
     fn test_all_tasks_empty() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         {
             let mut txn = storage.txn()?;
             let tasks = txn.all_tasks()?;
@@ -527,7 +538,7 @@ mod test {
     #[test]
     fn test_all_tasks_and_uuids() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();
         {
@@ -581,7 +592,7 @@ mod test {
     #[test]
     fn test_base_version_default() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         {
             let mut txn = storage.txn()?;
             assert_eq!(txn.base_version()?, DEFAULT_BASE_VERSION);
@@ -592,7 +603,7 @@ mod test {
     #[test]
     fn test_base_version_setting() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let u = Uuid::new_v4();
         {
             let mut txn = storage.txn()?;
@@ -609,7 +620,7 @@ mod test {
     #[test]
     fn test_operations() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();
         let uuid3 = Uuid::new_v4();
@@ -694,7 +705,7 @@ mod test {
     #[test]
     fn get_working_set_empty() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
 
         {
             let mut txn = storage.txn()?;
@@ -708,7 +719,7 @@ mod test {
     #[test]
     fn add_to_working_set() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();
 
@@ -731,7 +742,7 @@ mod test {
     #[test]
     fn clear_working_set() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();
 
@@ -762,7 +773,7 @@ mod test {
     #[test]
     fn set_working_set_item() -> anyhow::Result<()> {
         let tmp_dir = TempDir::new()?;
-        let mut storage = SqliteStorage::new(&tmp_dir.path())?;
+        let mut storage = SqliteStorage::new(&tmp_dir.path(), true)?;
         let uuid1 = Uuid::new_v4();
         let uuid2 = Uuid::new_v4();