Modified nim-lang#3472 to make its API more idiomatic.

examples/ssl/extradata.nim

@@ -1,14 +1,26 @@
 # Stores extra data inside the SSL context.
 import net
 
+let ctx = newContext()
+
 # Our unique index for storing foos
-let fooIndex = getSslContextExtraDataIndex()
+let fooIndex = ctx.getExtraDataIndex()
 # And another unique index for storing foos
-let barIndex = getSslContextExtraDataIndex()
+let barIndex = ctx.getExtraDataIndex()
 echo "got indexes ", fooIndex, " ", barIndex
 
-let ctx = newContext()
-assert ctx.getExtraData(fooIndex) == nil
-let foo: int = 5
-ctx.setExtraData(fooIndex, cast[pointer](foo))
-assert cast[int](ctx.getExtraData(fooIndex)) == foo
+try:
+  discard ctx.getExtraData(fooIndex)
+  assert false
+except IndexError:
+  echo("Success")
+
+type
+  FooRef = ref object of RootRef
+    foo: int
+
+let foo = FooRef(foo: 5)
+ctx.setExtraData(fooIndex, foo)
+doAssert ctx.getExtraData(fooIndex).FooRef == foo
+
+ctx.destroyContext()

lib/pure/net.nim

@@ -66,7 +66,7 @@
 ##
 
 {.deadCodeElim: on.}
-import nativesockets, os, strutils, parseutils, times
+import nativesockets, os, strutils, parseutils, times, sets
 export Port, `$`, `==`
 export Domain, SockType, Protocol
 
@@ -88,7 +88,10 @@ when defineSsl:
     SslProtVersion* = enum
       protSSLv2, protSSLv3, protTLSv1, protSSLv23
 
-    SslContext* = distinct SslCtx
+    SslContext* = ref object
+      context: SslCtx
+      extraInternalIndex: int
+      referencedData: HashSet[int]
 
     SslAcceptResult* = enum
       AcceptNoClient = 0, AcceptNoHandshake, AcceptSuccess
@@ -229,9 +232,10 @@ when defineSsl:
   ErrLoadBioStrings()
   OpenSSL_add_all_algorithms()
 
-  type SslContextExtraInternal = ref object
-    serverGetPskFunc: SslServerGetPskFunc
-    clientGetPskFunc: SslClientGetPskFunc
+  type
+    SslContextExtraInternal = ref object of RootRef
+      serverGetPskFunc: SslServerGetPskFunc
+      clientGetPskFunc: SslClientGetPskFunc
 
   proc raiseSSLError*(s = "") =
     ## Raises a new SSL error.
@@ -245,21 +249,33 @@ when defineSsl:
     var errStr = ErrErrorString(err, nil)
     raise newException(SSLError, $errStr)
 
-  proc getSslContextExtraDataIndex*(): cint =
+  proc getExtraDataIndex*(ctx: SSLContext): int =
     ## Retrieves unique index for storing extra data in SSLContext.
-    return SSL_CTX_get_ex_new_index(0, nil, nil, nil, nil)
+    result = SSL_CTX_get_ex_new_index(0, nil, nil, nil, nil).int
+    if result < 0:
+      raiseSSLError()
+
+  proc getExtraData*(ctx: SSLContext, index: int): RootRef =
+    ## Retrieves arbitrary data stored inside SSLContext.
+    if index notin ctx.referencedData:
+      raise newException(IndexError, "No data with that index.")
+    let res = ctx.context.SSL_CTX_get_ex_data(index.cint)
+    if cast[int](res) == 0:
+      raiseSSLError()
+    return cast[RootRef](res)
 
-  proc setExtraData*(ctx: SSLContext, index: cint, data: pointer) =
+  proc setExtraData*(ctx: SSLContext, index: int, data: RootRef) =
     ## Stores arbitrary data inside SSLContext. The unique `index`
     ## should be retrieved using getSslContextExtraDataIndex.
-    if SslCtx(ctx).SSL_CTX_set_ex_data(index, data) == -1:
-      raiseSSLError()
+    if index in ctx.referencedData:
+      GC_unref(getExtraData(ctx, index))
 
-  proc getExtraData*(ctx: SSLContext, index: cint): pointer =
-    ## Retrieves arbitrary data stored inside SSLContext.
-    return SslCtx(ctx).SSL_CTX_get_ex_data(index)
+    if ctx.context.SSL_CTX_set_ex_data(index.cint, cast[pointer](data)) == -1:
+      raiseSSLError()
 
-  let extraInternalIndex = getSslContextExtraDataIndex()
+    if index notin ctx.referencedData:
+      ctx.referencedData.incl(index)
+    GC_ref(data)
 
   # http://simplestcodings.blogspot.co.uk/2010/08/secure-server-client-using-openssl-in-c.html
   proc loadCertificates(ctx: SSL_CTX, certFile, keyFile: string) =
@@ -323,34 +339,41 @@ when defineSsl:
     discard newCTX.SSLCTXSetMode(SSL_MODE_AUTO_RETRY)
     newCTX.loadCertificates(certFile, keyFile)
 
-    result = SSLContext(newCTX)
+    result = SSLContext(context: newCTX, extraInternalIndex: 0,
+        referencedData: initSet[int]())
+    result.extraInternalIndex = getExtraDataIndex(result)
+    # The PSK callback functions assume the internal index is 0.
+    assert result.extraInternalIndex == 0
+
     let extraInternal = new(SslContextExtraInternal)
-    GC_ref(extraInternal)
-    result.setExtraData(extraInternalIndex, cast[pointer](extraInternal))
+    result.setExtraData(result.extraInternalIndex, extraInternal)
 
   proc getExtraInternal(ctx: SSLContext): SslContextExtraInternal =
-    return cast[SslContextExtraInternal](ctx.getExtraData(extraInternalIndex))
+    return SslContextExtraInternal(ctx.getExtraData(ctx.extraInternalIndex))
 
   proc destroyContext*(ctx: SSLContext) =
     ## Free memory referenced by SSLContext.
-    let extraInternal = ctx.getExtraInternal()
-    if extraInternal != nil:
-      GC_unref(extraInternal)
-    SSLCTX(ctx).SSL_CTX_free()
+
+    # We assume here that OpenSSL's internal indexes increase by 1 each time.
+    # That means we can assume that the next internal index is the length of
+    # extra data indexes.
+    for i in ctx.referencedData:
+      GC_unref(getExtraData(ctx, i).RootRef)
+    ctx.context.SSL_CTX_free()
 
   proc `pskIdentityHint=`*(ctx: SSLContext, hint: string) =
     ## Sets the identity hint passed to server.
     ##
     ## Only used in PSK ciphersuites.
-    if SSLCTX(ctx).SSL_CTX_use_psk_identity_hint(hint) <= 0:
+    if ctx.context.SSL_CTX_use_psk_identity_hint(hint) <= 0:
       raiseSSLError()
 
   proc clientGetPskFunc*(ctx: SSLContext): SslClientGetPskFunc =
     return ctx.getExtraInternal().clientGetPskFunc
 
   proc pskClientCallback(ssl: SslPtr; hint: cstring; identity: cstring; max_identity_len: cuint; psk: ptr cuchar;
     max_psk_len: cuint): cuint {.cdecl.} =
-    let ctx = SSLContext(ssl.SSL_get_SSL_CTX)
+    let ctx = SSLContext(context: ssl.SSL_get_SSL_CTX, extraInternalIndex: 0)
     let hintString = if hint == nil: nil else: $hint
     let (identityString, pskString) = (ctx.clientGetPskFunc)(hintString)
     if psk.len.cuint > max_psk_len:
@@ -369,13 +392,14 @@ when defineSsl:
     ##
     ## Only used in PSK ciphersuites.
     ctx.getExtraInternal().clientGetPskFunc = fun
-    SslCtx(ctx).SSL_CTX_set_psk_client_callback(if fun == nil: nil else: pskClientCallback)
+    ctx.context.SSL_CTX_set_psk_client_callback(
+        if fun == nil: nil else: pskClientCallback)
 
   proc serverGetPskFunc*(ctx: SSLContext): SslServerGetPskFunc =
     return ctx.getExtraInternal().serverGetPskFunc
 
   proc pskServerCallback(ssl: SslCtx; identity: cstring; psk: ptr cuchar; max_psk_len: cint): cuint {.cdecl.} =
-    let ctx = SSLContext(ssl.SSL_get_SSL_CTX)
+    let ctx = SSLContext(context: ssl.SSL_get_SSL_CTX, extraInternalIndex: 0)
     let pskString = (ctx.serverGetPskFunc)($identity)
     if psk.len.cint > max_psk_len:
       return 0
@@ -388,7 +412,7 @@ when defineSsl:
     ##
     ## Only used in PSK ciphersuites.
     ctx.getExtraInternal().serverGetPskFunc = fun
-    SslCtx(ctx).SSL_CTX_set_psk_server_callback(if fun == nil: nil
+    ctx.context.SSL_CTX_set_psk_server_callback(if fun == nil: nil
                                                 else: pskServerCallback)
 
   proc getPskIdentity*(socket: Socket): string =
@@ -409,7 +433,7 @@ when defineSsl:
     assert (not socket.isSSL)
     socket.isSSL = true
     socket.sslContext = ctx
-    socket.sslHandle = SSLNew(SSLCTX(socket.sslContext))
+    socket.sslHandle = SSLNew(socket.sslContext.context)
     socket.sslNoHandshake = false
     socket.sslHasPeekChar = false
     if socket.sslHandle == nil: