Publish GRPCRequestHeaders as a protocol

So we can make the property a dictionary later, by just extending
NSMutableDictionary to conform to the protocol.

1 files changed, 120 insertions, 0 deletions

diff --git a/src/objective-c/GRPCClient/private/GRPCRequestHeaders.m b/src/objective-c/GRPCClient/private/GRPCRequestHeaders.m
new file mode 100644
index 0000000000..d4bbbdf84a
--- /dev/null
+++ b/src/objective-c/GRPCClient/private/GRPCRequestHeaders.m
@@ -0,0 +1,120 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#import "GRPCRequestHeaders.h"
+
+#import <Foundation/Foundation.h>
+
+#import "GRPCCall.h"
+#import "NSDictionary+GRPC.h"
+
+// Used by the setters.
+static NSString* NormalizeKey(NSString* key) {
+  if (!key) {
+    [NSException raise:NSInvalidArgumentException format:@"Key cannot be nil"];
+  }
+  if (![key canBeConvertedToEncoding:NSASCIIStringEncoding]) {
+    [NSException raise:NSInvalidArgumentException
+                format:@"Key %@ contains non-ASCII characters", key];
+  }
+  return key.lowercaseString;
+}
+
+// Precondition: key isn't nil.
+static void CheckKeyValuePairIsValid(NSString *key, id value) {
+  if ([key hasSuffix:@"-bin"]) {
+    if (![value isKindOfClass:NSData.class]) {
+      [NSException raise:NSInvalidArgumentException
+                  format:@"Expected NSData value for header %@ ending in \"-bin\", "
+       @"instead got %@", key, value];
+    }
+  } else {
+    if (![value isKindOfClass:NSString.class]) {
+      [NSException raise:NSInvalidArgumentException
+                  format:@"Expected NSString value for header %@ not ending in \"-bin\", "
+       @"instead got %@", key, value];
+    }
+  }
+}
+
+@implementation GRPCRequestHeaders {
+  __weak GRPCCall *_call;
+  NSMutableDictionary *_proxy;
+}
+
+- (instancetype)initWithCall:(GRPCCall *)call {
+  if ((self = [super init])) {
+    _call = call;
+    _proxy = [NSMutableDictionary dictionary];
+  }
+  return self;
+}
+
+- (void)checkCallIsNotStarted {
+  if (_call.state != GRXWriterStateNotStarted) {
+    [NSException raise:@"Invalid modification"
+                format:@"Cannot modify request headers after call is started"];
+  }
+}
+
+- (id)objectForKeyedSubscript:(NSString *)key {
+  return _proxy[key.lowercaseString];
+}
+
+- (void)setObject:(id)obj forKeyedSubscript:(NSString *)key {
+  [self checkCallIsNotStarted];
+  key = NormalizeKey(key);
+  CheckKeyValuePairIsValid(key, obj);
+  _proxy[key] = obj;
+}
+
+- (void)removeObjectForKey:(NSString *)key {
+  [self checkCallIsNotStarted];
+  [_proxy removeObjectForKey:NormalizeKey(key)];
+}
+
+- (void)removeAllObjects {
+  [self checkCallIsNotStarted];
+  [_proxy removeAllObjects];
+}
+
+// TODO(jcanizales): Just forward all invocations?
+
+- (NSUInteger)count {
+  return _proxy.count;
+}
+
+- (grpc_metadata *)grpc_metadataArray {
+  return _proxy.grpc_metadataArray;
+}
+@end
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