#2: support building with very old apt

Author: FauxFaux

Cargo.toml

@@ -24,3 +24,7 @@ libc = "0.2"
 [dev-dependencies]
 boolinator = "2"
 itertools = "0.7"
+
+[features]
+default = []
+ye-olde-apt = []

README.md

@@ -21,6 +21,12 @@ While the code in this crate is available under a permissive MIT license,
 `libapt-pkg-dev` must be installed. The [`gcc`](https://crates.io/crates/gcc)
   crate is used to try and find a native compiler.
 
+The `ye-olde-apt` feature provides support for `apt <1.2` (Ubuntu 14.04 (Trusty),
+Debian 7 (Jessie) (2015)). This works by just deleting methods which are not
+available in that version. See
+[#2](https://github.com/FauxFaux/apt-pkg-native-rs/issues/2#issuecomment-351180818).
+
+
 ### Thread safety
 
 It is intended that the crate should be usable from multiple threads.

apt-pkg-c/lib.cpp

@@ -80,11 +80,13 @@ extern "C" {
     // ver_iter access
     const char *ver_iter_version(PVerIterator *iterator);
     const char *ver_iter_section(PVerIterator *iterator);
+    const char *ver_iter_arch(PVerIterator *iterator);
+
+#ifndef YE_OLDE_APT
     const char *ver_iter_source_package(PVerIterator *iterator);
     const char *ver_iter_source_version(PVerIterator *iterator);
-    const char *ver_iter_arch(PVerIterator *iterator);
     int32_t ver_iter_priority(PVerIterator *iterator);
-
+#endif
 
     // ver_file_iter creation and deletion
     PVerFileIterator *ver_iter_ver_file_iter(PVerIterator *iterator);
@@ -227,6 +229,8 @@ const char *ver_iter_section(PVerIterator *wrapper) {
    return wrapper->iterator.Section();
 }
 
+#ifndef YE_OLDE_APT
+
 const char *ver_iter_source_package(PVerIterator *wrapper) {
     return wrapper->iterator.SourcePkgName();
 }
@@ -235,16 +239,19 @@ const char *ver_iter_source_version(PVerIterator *wrapper) {
     return wrapper->iterator.SourceVerStr();
 }
 
-const char *ver_iter_arch(PVerIterator *wrapper) {
-    return wrapper->iterator.Arch();
-}
-
 int32_t ver_iter_priority(PVerIterator *wrapper) {
     // The priority is a "short", which is roughly a (signed) int16_t;
     // going bigger just in case
     return wrapper->cache->cache_file->GetPolicy()->GetPriority(wrapper->iterator);
 }
 
+#endif
+
+const char *ver_iter_arch(PVerIterator *wrapper) {
+    return wrapper->iterator.Arch();
+}
+
+
 PVerFileIterator *ver_iter_ver_file_iter(PVerIterator *wrapper) {
     PVerFileIterator *new_wrapper = new PVerFileIterator();
     new_wrapper->iterator = wrapper->iterator.FileList();

build.rs

@@ -5,9 +5,15 @@ const SRC: &str = "apt-pkg-c/lib.cpp";
 fn main() {
     println!("cargo:rerun-if-changed={}", SRC);
 
-    gcc::Build::new()
-        .file(SRC)
-        .cpp(true)
-        .flag("-std=gnu++11")
-        .compile("libapt-pkg-c.a");
+    let mut build = gcc::Build::new();
+    build.file(SRC);
+    build.cpp(true);
+    build.flag("-std=gnu++11");
+
+    #[cfg(feature="ye-olde-apt")]
+    {
+        build.define("YE_OLDE_APT", "1");
+    }
+
+    build.compile("libapt-pkg-c.a");
 }

src/raw.rs

@@ -67,9 +67,15 @@ extern "C" {
 
     pub fn ver_iter_version(iterator: PVerIterator) -> *mut c_char;
     pub fn ver_iter_section(iterator: PVerIterator) -> *mut c_char;
+
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn ver_iter_source_package(iterator: PVerIterator) -> *mut c_char;
+
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn ver_iter_source_version(iterator: PVerIterator) -> *mut c_char;
     pub fn ver_iter_arch(iterator: PVerIterator) -> *mut c_char;
+
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn ver_iter_priority(iterator: PVerIterator) -> i32;
 
     pub fn ver_iter_ver_file_iter(iterator: PVerIterator) -> PVerFileIterator;

src/sane.rs

@@ -238,20 +238,23 @@ impl<'c> VerView<'c> {
         unsafe { make_owned_ascii_string(raw::ver_iter_section(self.ptr)) }
     }
 
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn source_package(&self) -> String {
         unsafe {
             make_owned_ascii_string(raw::ver_iter_source_package(self.ptr))
                 .expect("versions always have a source package")
         }
     }
 
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn source_version(&self) -> String {
         unsafe {
             make_owned_ascii_string(raw::ver_iter_source_version(self.ptr))
                 .expect("versions always have a source_version")
         }
     }
 
+    #[cfg(not(feature="ye-olde-apt"))]
     pub fn priority(&self) -> i32 {
         unsafe { raw::ver_iter_priority(self.ptr) }
     }

src/simple.rs

@@ -41,8 +41,12 @@ pub struct Version {
     pub version: String,
     pub arch: String,
     pub section: Option<String>,
+
+    #[cfg(not(feature="ye-olde-apt"))]
     pub source_package: String,
+    #[cfg(not(feature="ye-olde-apt"))]
     pub source_version: String,
+    #[cfg(not(feature="ye-olde-apt"))]
     pub priority: i32,
 }
 
@@ -53,8 +57,11 @@ impl Version {
             version: view.version(),
             arch: view.arch(),
             section: view.section(),
+            #[cfg(not(feature="ye-olde-apt"))]
             source_package: view.source_package(),
+            #[cfg(not(feature="ye-olde-apt"))]
             source_version: view.source_version(),
+            #[cfg(not(feature="ye-olde-apt"))]
             priority: view.priority(),
         }
     }
@@ -66,13 +73,16 @@ impl fmt::Display for Version {
         if let Some(ref section) = self.section {
             write!(f, " in {}", section)?;
         }
+        #[cfg(not(feature="ye-olde-apt"))]
         write!(
             f,
             " from {}:{} at {}",
             self.source_package,
             self.source_version,
             self.priority,
-        )
+        )?;
+
+        Ok(())
     }
 }