crypto: do not move half-filled write head

indutny · indutny · commit 4ae96c885bd3 · 2013-06-26T12:36:56.000+02:00
Might cause write head running over read head, when there were no
allocation and `Commit()` was called. Source of at least one test
failure on windows (`simple/test-https-drain.js`).
diff --git a/src/node_crypto_bio.cc b/src/node_crypto_bio.cc
@@ -315,6 +315,7 @@ void NodeBIO::Write(const char* data, size_t size) {
 
     // Go to next buffer if there still are some bytes to write
     if (left != 0) {
+      assert(write_head_->write_pos_ == kBufferLength);
       TryAllocateForWrite();
       write_head_ = write_head_->next_;
     }
@@ -342,7 +343,8 @@ void NodeBIO::Commit(size_t size) {
   // Allocate new buffer if write head is full,
   // and there're no other place to go
   TryAllocateForWrite();
-  write_head_ = write_head_->next_;
+  if (write_head_->write_pos_ == kBufferLength)
+    write_head_ = write_head_->next_;
 }
 
 

Original file line number	Diff line number	Diff line change
`@@ -315,6 +315,7 @@ void NodeBIO::Write(const char* data, size_t size) {`
`315`	`315`
`316`	`316`	`// Go to next buffer if there still are some bytes to write`
`317`	`317`	`if (left != 0) {`
	`318`	`+ assert(write_head_->write_pos_ == kBufferLength);`
`318`	`319`	`TryAllocateForWrite();`
`319`	`320`	`write_head_ = write_head_->next_;`
`320`	`321`	`}`
`@@ -342,7 +343,8 @@ void NodeBIO::Commit(size_t size) {`
`342`	`343`	`// Allocate new buffer if write head is full,`
`343`	`344`	`// and there're no other place to go`
`344`	`345`	`TryAllocateForWrite();`
`345`		`- write_head_ = write_head_->next_;`
	`346`	`+ if (write_head_->write_pos_ == kBufferLength)`
	`347`	`+ write_head_ = write_head_->next_;`
`346`	`348`	`}`
`347`	`349`
`348`	`350`