Simplify API by eliminating Database and hiding TransactionSet

There's not much use for these types and they just make the API harder
to use.

This change now mutex locks the API by acquiring a global TransactionSet
which is "cleaned" after each use.

Author: tony-iqlusion

Cargo.lock

@@ -19,4 +19,3 @@ failure = "0.1"
 lazy_static = "1"
 libc = { version = "0.2", default-features = false }
 rpmlib-sys = { version = "0.4", path = "../rpmlib-sys" }
-streaming-iterator = "0.1"

rpmlib/Cargo.toml

@@ -1,274 +1,54 @@
-//! RPM database binding
-
-use failure::Error;
-use libc;
-use rpmlib_sys::rpmlib;
-use std::ffi::CString;
-use std::ptr;
-use streaming_iterator::StreamingIterator;
-
-use header::Header;
-use tag::Tag;
-use ts::TransactionSet;
-
-/// RPM database access: this type provides a handle to an RPM database valid
-/// for the lifetime of a transaction.
-///
-/// The database used is whichever one is configured as the `_dbpath` in the
-/// in the global macro context. By default this is unset: you will need to
-/// call `rpmlib::read_config(None)` to read the default "rpmrc" configuration.
-///
-/// # Example
-///
-/// Finding the "rpm-devel" RPM in the database:
-///
-/// ```
-/// use rpmlib::{self, Database, StreamingIterator, Txn, Tag, TagData};
-///
-/// rpmlib::config::read_file(None).unwrap();
-///
-/// let mut txn = Txn::create().unwrap();
-/// let mut db = Database::open(&mut txn, false).unwrap();
-/// let mut matches = db.find(Tag::NAME, "rpm-devel");
-/// let package = matches.next().unwrap();
-///
-/// match package.get(Tag::NAME) {
-///     TagData::Str(ref s) => println!("package name: {}", s),
-///     _ => ()
-/// }
-///
-/// match package.get(Tag::DESCRIPTION) {
-///     TagData::Str(ref s) => println!("package description: {}", s),
-///     _ => ()
-/// }
-/// ```
-pub struct Database<'ts> {
-    /// Borrows the `TransactionSet` mutably so we can control its database
-    ts: &'ts mut TransactionSet,
-}
-
-impl<'ts> Database<'ts> {
-    /// Open the default database
-    pub fn open(ts: &'ts mut TransactionSet, writable: bool) -> Result<Self, Error> {
-        let dbmode = if writable {
-            libc::O_RDWR
-        } else {
-            libc::O_RDONLY
-        };
-
-        let ts_ptr = ts.as_ptr();
-        if unsafe { ts.ffi().rpmtsOpenDB(ts_ptr, dbmode) } != 0 {
-            // TODO: check the _dbpath macro and see if it's set?
-            bail!("couldn't open _dbpath (writable: {})!", writable);
-        }
-
-        Ok(Self { ts })
-    }
-
-    /// Return an iterator over all of the packages in the database.
-    pub fn packages<'db>(&'db mut self) -> MatchIterator<'db, 'ts> {
-        let ts_ptr = self.ts.as_ptr();
-        let iter_ptr = unsafe {
-            self.ts
-                .ffi()
-                .rpmtsInitIterator(ts_ptr, rpmlib::rpmTag_e_RPMTAG_NAME, ptr::null(), 0)
-        };
-
-        MatchIterator::new(self, iter_ptr)
-    }
-
-    /// Find packages with a search key that exatcly matches the given tag.
-    ///
-    /// Panics if the glob contains null bytes.
-    #[inline]
-    pub fn find<'db, K>(&'db mut self, tag: Tag, key: K) -> MatchIterator<'db, 'ts>
-    where
-        K: AsRef<str>,
-    {
-        let mut iter = self.packages();
-        iter.find(tag, key);
-        iter
-    }
-
-    /// Find all packages with the given tag that match the given "glob"
-    ///
-    /// Panics if the glob contains null bytes.
-    #[inline]
-    pub fn find_glob<'db, G>(&'db mut self, tag: Tag, glob: &G) -> MatchIterator<'db, 'ts>
-    where
-        G: AsRef<str>,
-    {
-        let mut iter = self.packages();
-        iter.glob(tag, glob);
-        iter
-    }
-
-    /// Find all packages with the given tag that match the given regex
-    ///
-    /// Panics if the regex contains null bytes.
-    #[inline]
-    pub fn find_regex<'db, R>(&'db mut self, tag: Tag, regex: &R) -> MatchIterator<'db, 'ts>
-    where
-        R: AsRef<str>,
-    {
-        let mut iter = self.packages();
-        iter.regex(tag, regex);
-        iter
-    }
-
-    /// Obtain the TransactionSet this database was opened under
-    #[inline]
-    pub fn transaction_set(&mut self) -> &mut TransactionSet {
-        &mut self.ts
-    }
-}
-
-impl<'ts> Drop for Database<'ts> {
-    fn drop(&mut self) {
-        unsafe {
-            let ts_ptr = self.ts.as_ptr();
-            self.ts.ffi().rpmtsCloseDB(ts_ptr);
-        }
-    }
-}
-
-/// Iterator over the matches from a database query
-pub struct MatchIterator<'db, 'ts: 'db> {
-    // TODO: allow Header to borrow mut borrow the database for a safer memory
-    // model. See notes in `header.rs`
-    #[allow(dead_code)]
-    db: &'db mut Database<'ts>,
-    ptr: rpmlib::rpmdbMatchIterator,
-    next_item: Option<Header>,
-}
-
-impl<'db, 'ts> MatchIterator<'db, 'ts> {
-    pub(crate) fn new(db: &'db mut Database<'ts>, ptr: rpmlib::rpmdbMatchIterator) -> Self {
-        assert!(!ptr.is_null(), "iterator pointer is NULL!");
-        Self {
-            db,
-            ptr,
-            next_item: None,
-        }
-    }
-
-    /// Find packages with a search key that exatcly matches the given tag.
-    ///
-    /// Panics if the glob contains null bytes.
-    pub fn find<K>(&mut self, tag: Tag, key: K) -> &mut Self
-    where
-        K: AsRef<str>,
-    {
-        let key_cstr = CString::new(key.as_ref()).unwrap();
-
-        unsafe {
-            self.db.ts.ffi().rpmdbSetIteratorRE(
-                self.ptr,
-                tag as rpmlib::rpm_tag_t,
-                rpmlib::rpmMireMode_e_RPMMIRE_STRCMP,
-                key_cstr.as_ptr(),
-            );
-        }
-
-        self
-    }
-
-    /// Find all packages with the given tag that match the given "glob"
-    ///
-    /// Panics if the glob contains null bytes.
-    pub fn glob<G>(&mut self, tag: Tag, glob: &G) -> &mut Self
-    where
-        G: AsRef<str>,
-    {
-        let glob_cstr = CString::new(glob.as_ref()).unwrap();
-
-        unsafe {
-            self.db.ts.ffi().rpmdbSetIteratorRE(
-                self.ptr,
-                tag as rpmlib::rpm_tag_t,
-                rpmlib::rpmMireMode_e_RPMMIRE_GLOB,
-                glob_cstr.as_ptr(),
-            );
-        }
-
-        self
-    }
-
-    /// Find all packages with the given tag that match the given regex
-    ///
-    /// Panics if the regex contains null bytes.
-    pub fn regex<R>(&mut self, tag: Tag, regex: &R) -> &mut Self
-    where
-        R: AsRef<str>,
-    {
-        let regex_cstr = CString::new(regex.as_ref()).unwrap();
-
-        unsafe {
-            self.db.ts.ffi().rpmdbSetIteratorRE(
-                self.ptr,
-                tag as rpmlib::rpm_tag_t,
-                rpmlib::rpmMireMode_e_RPMMIRE_REGEX,
-                regex_cstr.as_ptr(),
-            );
-        }
-
-        self
-    }
-}
-
-impl<'db, 'ts> StreamingIterator for MatchIterator<'db, 'ts> {
-    type Item = Header;
-
-    fn advance(&mut self) {
-        let header_ptr = unsafe { self.db.ts.ffi().rpmdbNextIterator(self.ptr) };
-
-        if header_ptr.is_null() {
-            self.next_item = None
-        } else {
-            self.next_item = Some(Header::new(header_ptr))
-        }
-    }
-
-    fn get(&self) -> Option<&Header> {
-        self.next_item.as_ref()
-    }
-}
-
-impl<'db, 'ts> Drop for MatchIterator<'db, 'ts> {
-    fn drop(&mut self) {
-        unsafe {
-            self.db.ts.ffi().rpmdbFreeIterator(self.ptr);
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use {config, Database, Tag, TagData, Txn};
-    use streaming_iterator::StreamingIterator;
-
-    /// The `.rpm` containing rpmlib itself
-    const TEST_PACKAGE: &str = "rpm-devel";
-
-    #[test]
-    fn test_package_lookup() {
-        // Read the default config
-        // TODO: create a mock RPM database for testing
-        config::read_file(None).unwrap();
-
-        let mut txn = Txn::create().unwrap();
-        let mut db = Database::open(&mut txn, false).unwrap();
-        let mut matches = db.find(Tag::NAME, TEST_PACKAGE);
-
-        if let Some(package) = matches.next() {
-            match package.get(Tag::NAME) {
-                TagData::Str(ref s) => assert_eq!(s, &TEST_PACKAGE),
-                _ => panic!("unexpected result for package.get()!"),
-            }
-        } else {
-            panic!("expected 1 result, got 0!");
-        }
-
-        assert!(matches.next().is_none(), "expected one result, got more!");
-    }
+//! RPM database access
+//!
+//! The database used is whichever one is configured as the `_dbpath` in the
+//! in the global macro context. By default this is unset: you will need to
+//! call `rpmlib::config::read_file(None)` to read the default "rpmrc"
+//! configuration.
+//!
+//! # Example
+//!
+//! Finding the "rpm-devel" RPM in the database:
+//!
+//! ```
+//! use rpmlib::{self, Tag};
+//!
+//! rpmlib::config::read_file(None).unwrap();
+//!
+//! let mut matches = rpmlib::db::find(Tag::NAME, "rpm-devel");
+//! let headers = matches.next().unwrap();
+//!
+//! println!("package name: {}", headers.name());
+//! println!("package description: {}", headers.description());
+//! ```
+
+use {MatchIterator, Tag};
+
+/// Find all packages in the RPM database
+pub fn all_packages() -> MatchIterator {
+    MatchIterator::new(Tag::NAME, None)
+}
+
+/// Find packages with a search key that exactly matches the given tag.
+///
+/// Panics if the glob contains null bytes.
+pub fn find(tag: Tag, key: &str) -> MatchIterator {
+    MatchIterator::new(tag, Some(key))
+}
+
+/// Find all packages with the given tag that match the given "glob"
+///
+/// Panics if the glob contains null bytes.
+pub fn glob(tag: Tag, glob: &str) -> MatchIterator {
+    let mut iter = all_packages();
+    iter.glob(tag, glob);
+    iter
+}
+
+/// Find all packages with the given tag that match the given regex
+///
+/// Panics if the regex contains null bytes.
+pub fn regex(tag: Tag, regex: &str) -> MatchIterator {
+    let mut iter = all_packages();
+    iter.regex(tag, regex);
+    iter
 }