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Come to think of it, changing comparison logic unexpectedly is a bad idea.

This commit is contained in:
Artem 2018-07-14 16:22:56 +02:00
parent e959c770e2
commit 71a5a43e33
1 changed files with 16 additions and 21 deletions
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37
src/wasapi/device.rs
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@ -542,10 +542,6 @@ impl PartialEq for Device {
// //
// In this code section we're trying to use the GetId method for the device comparison, cf. // In this code section we're trying to use the GetId method for the device comparison, cf.
// https://docs.microsoft.com/en-us/windows/desktop/api/mmdeviceapi/nf-mmdeviceapi-immdevice-getid // https://docs.microsoft.com/en-us/windows/desktop/api/mmdeviceapi/nf-mmdeviceapi-immdevice-getid
//
// If `GetId` mysteriously fails then we fall back to pointer comparison
// (we could panic, treating the `GetId` failure as something unexpected,
// but I simply don't know how reliable the `GetId` on Windows is).
unsafe { unsafe {
struct IdRAII (LPWSTR); struct IdRAII (LPWSTR);
/// RAII for device IDs. /// RAII for device IDs.
@ -556,25 +552,24 @@ impl PartialEq for Device {
} }
let mut id1: LPWSTR = ptr::null_mut(); let mut id1: LPWSTR = ptr::null_mut();
let rc1 = (*self.device).GetId(&mut id1); let rc1 = (*self.device).GetId(&mut id1);
if rc1 == winerror::S_OK { // GetId only fails with E_OUTOFMEMORY and if it does, we're probably dead already.
let id1 = IdRAII(id1); // Plus it won't do to change the device comparison logic unexpectedly.
let mut id2: LPWSTR = ptr::null_mut(); if rc1 != winerror::S_OK {panic! ("cpal: GetId failure: {}", rc1)}
let rc2 = (*other.device).GetId(&mut id2); let id1 = IdRAII(id1);
if rc2 == winerror::S_OK { let mut id2: LPWSTR = ptr::null_mut();
let id2 = IdRAII(id2); let rc2 = (*other.device).GetId(&mut id2);
// 16-bit null-terminated comparison. if rc2 != winerror::S_OK {panic! ("cpal: GetId failure: {}", rc1)}
let mut offset = 0; let id2 = IdRAII(id2);
loop { // 16-bit null-terminated comparison.
let w1: WCHAR = *id1.0.offset(offset); let mut offset = 0;
let w2: WCHAR = *id2.0.offset(offset); loop {
if w1 == 0 && w2 == 0 {return true} let w1: WCHAR = *id1.0.offset(offset);
if w1 != w2 {return false} let w2: WCHAR = *id2.0.offset(offset);
offset += 1; if w1 == 0 && w2 == 0 {return true}
} if w1 != w2 {return false}
} offset += 1;
} }
} }
self.device == other.device
} }
} }