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// This is based on chrome/renderer/pepper/pepper_flash_renderer_host.cc:
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "pepper_flash_renderer_host_qt.h"

#include <map>
#include <vector>

#include "base/lazy_instance.h"
#include "base/metrics/histogram.h"
#include "base/strings/string_util.h"
#include "content/public/renderer/pepper_plugin_instance.h"
#include "content/public/renderer/render_thread.h"
#include "content/public/renderer/renderer_ppapi_host.h"
#include "ipc/ipc_message_macros.h"
#include "net/http/http_util.h"
#include "ppapi/c/pp_errors.h"
#include "ppapi/c/trusted/ppb_browser_font_trusted.h"
#include "ppapi/host/dispatch_host_message.h"
#include "ppapi/proxy/host_dispatcher.h"
#include "ppapi/proxy/ppapi_messages.h"
#include "ppapi/proxy/resource_message_params.h"
#include "ppapi/proxy/serialized_structs.h"
#include "ppapi/thunk/enter.h"
#include "ppapi/thunk/ppb_image_data_api.h"
#include "skia/ext/platform_canvas.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "third_party/skia/include/core/SkMatrix.h"
#include "third_party/skia/include/core/SkPaint.h"
#include "third_party/skia/include/core/SkPoint.h"
#include "third_party/skia/include/core/SkTypeface.h"
#include "third_party/skia/include/private/SkTemplates.h"
#include "ui/gfx/geometry/rect.h"
#include "url/gurl.h"

using ppapi::thunk::EnterResourceNoLock;
using ppapi::thunk::PPB_ImageData_API;

namespace {

// Some non-simple HTTP request headers that Flash may set.
// (Please see http://www.w3.org/TR/cors/#simple-header for the definition of
// simple headers.)
//
// The list and the enum defined below are used to collect data about request
// headers used in PPB_Flash.Navigate() calls, in order to understand the impact
// of rejecting PPB_Flash.Navigate() requests with non-simple headers.
//
// TODO(yzshen): We should be able to remove the histogram recording code once
// we get the answer.
const char* const kRejectedHttpRequestHeaders[] = {
    "authorization",     //
    "cache-control",     //
    "content-encoding",  //
    "content-md5",       //
    "content-type",      // If the media type is not one of those covered by the
    // simple header definition.
    "expires",           //
    "from",              //
    "if-match",          //
    "if-none-match",     //
    "if-range",          //
    "if-unmodified-since",  //
    "pragma",               //
    "referer"               //
};

// Please note that new entries should be added right above
// FLASH_NAVIGATE_USAGE_ENUM_COUNT, and existing entries shouldn't be re-ordered
// or removed, since this ordering is used in a histogram.
enum FlashNavigateUsage {
    // This section must be in the same order as kRejectedHttpRequestHeaders.
    REJECT_AUTHORIZATION = 0,
    REJECT_CACHE_CONTROL,
    REJECT_CONTENT_ENCODING,
    REJECT_CONTENT_MD5,
    REJECT_CONTENT_TYPE,
    REJECT_EXPIRES,
    REJECT_FROM,
    REJECT_IF_MATCH,
    REJECT_IF_NONE_MATCH,
    REJECT_IF_RANGE,
    REJECT_IF_UNMODIFIED_SINCE,
    REJECT_PRAGMA,
    REJECT_REFERER,

    // The navigate request is rejected because of headers not listed above
    // (e.g., custom headers).
    REJECT_OTHER_HEADERS,

    // Total number of rejected navigate requests.
    TOTAL_REJECTED_NAVIGATE_REQUESTS,

    // Total number of navigate requests.
    TOTAL_NAVIGATE_REQUESTS,
    FLASH_NAVIGATE_USAGE_ENUM_COUNT
};

static base::LazyInstance<std::map<std::string, FlashNavigateUsage> >
g_rejected_headers = LAZY_INSTANCE_INITIALIZER;

bool IsSimpleHeader(const std::string& lower_case_header_name,
                    const std::string& header_value)
{
    if (lower_case_header_name == "accept" ||
            lower_case_header_name == "accept-language" ||
            lower_case_header_name == "content-language")
        return true;

    if (lower_case_header_name == "content-type") {
        std::string lower_case_mime_type;
        std::string lower_case_charset;
        bool had_charset = false;
        net::HttpUtil::ParseContentType(header_value,
                                        &lower_case_mime_type,
                                        &lower_case_charset,
                                        &had_charset,
                                        NULL);
        return lower_case_mime_type == "application/x-www-form-urlencoded" ||
                lower_case_mime_type == "multipart/form-data" ||
                lower_case_mime_type == "text/plain";
    }

    return false;
}

void RecordFlashNavigateUsage(FlashNavigateUsage usage)
{
    DCHECK_NE(FLASH_NAVIGATE_USAGE_ENUM_COUNT, usage);
    UMA_HISTOGRAM_ENUMERATION(
                "Plugin.FlashNavigateUsage",
                usage,
                FLASH_NAVIGATE_USAGE_ENUM_COUNT);
}

}  // namespace

namespace QtWebEngineCore {

PepperFlashRendererHostQt::PepperFlashRendererHostQt(
        content::RendererPpapiHost* host,
        PP_Instance instance,
        PP_Resource resource)
    : ResourceHost(host->GetPpapiHost(), instance, resource),
      host_(host),
      weak_factory_(this)
{
}

PepperFlashRendererHostQt::~PepperFlashRendererHostQt() {
    // This object may be destroyed in the middle of a sync message. If that is
    // the case, make sure we respond to all the pending navigate calls.
    std::vector<ppapi::host::ReplyMessageContext>::reverse_iterator it;
    for (it = navigate_replies_.rbegin(); it != navigate_replies_.rend(); ++it)
        SendReply(*it, IPC::Message());
}

int32_t PepperFlashRendererHostQt::OnResourceMessageReceived(
        const IPC::Message& msg,
        ppapi::host::HostMessageContext* context)
{
    PPAPI_BEGIN_MESSAGE_MAP(PepperFlashRendererHostQt, msg)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_Flash_GetProxyForURL,
                                              OnGetProxyForURL)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_Flash_SetInstanceAlwaysOnTop,
                                              OnSetInstanceAlwaysOnTop)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_Flash_DrawGlyphs,
                                              OnDrawGlyphs)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_Flash_Navigate, OnNavigate)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_Flash_IsRectTopmost,
                                              OnIsRectTopmost)
            PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_Flash_InvokePrinting,
                                                OnInvokePrinting)
            PPAPI_END_MESSAGE_MAP()
            return PP_ERROR_FAILED;
}

int32_t PepperFlashRendererHostQt::OnGetProxyForURL(
        ppapi::host::HostMessageContext* host_context,
        const std::string& url)
{
    GURL gurl(url);
    if (!gurl.is_valid())
        return PP_ERROR_FAILED;
    std::string proxy;
    bool result = content::RenderThread::Get()->ResolveProxy(gurl, &proxy);
    if (!result)
        return PP_ERROR_FAILED;
    host_context->reply_msg = PpapiPluginMsg_Flash_GetProxyForURLReply(proxy);
    return PP_OK;
}

int32_t PepperFlashRendererHostQt::OnSetInstanceAlwaysOnTop(
        ppapi::host::HostMessageContext* host_context,
        bool on_top)
{
    content::PepperPluginInstance* plugin_instance =
            host_->GetPluginInstance(pp_instance());
    if (plugin_instance)
        plugin_instance->SetAlwaysOnTop(on_top);
    return PP_OK;
}

int32_t PepperFlashRendererHostQt::OnDrawGlyphs(
        ppapi::host::HostMessageContext* host_context,
        ppapi::proxy::PPBFlash_DrawGlyphs_Params params)
{
    if (params.glyph_indices.size() != params.glyph_advances.size() ||
            params.glyph_indices.empty())
        return PP_ERROR_FAILED;

    return PP_OK;
}

// CAUTION: This code is subtle because Navigate is a sync call which may
// cause re-entrancy or cause the instance to be destroyed. If the instance
// is destroyed we need to ensure that we respond to all outstanding sync
// messages so that the plugin process does not remain blocked.
int32_t PepperFlashRendererHostQt::OnNavigate(
        ppapi::host::HostMessageContext* host_context,
        const ppapi::URLRequestInfoData& data,
        const std::string& target,
        bool from_user_action)
{
    // If our PepperPluginInstance is already destroyed, just return a failure.
    content::PepperPluginInstance* plugin_instance =
            host_->GetPluginInstance(pp_instance());
    if (!plugin_instance)
        return PP_ERROR_FAILED;

    std::map<std::string, FlashNavigateUsage>& rejected_headers =
            g_rejected_headers.Get();
    if (rejected_headers.empty()) {
        for (size_t i = 0; i < arraysize(kRejectedHttpRequestHeaders); ++i)
            rejected_headers[kRejectedHttpRequestHeaders[i]] =
                    static_cast<FlashNavigateUsage>(i);
    }

    net::HttpUtil::HeadersIterator header_iter(
                data.headers.begin(), data.headers.end(), "\n\r");
    bool rejected = false;
    while (header_iter.GetNext()) {
        std::string lower_case_header_name =
                base::ToLowerASCII(header_iter.name());
        if (!IsSimpleHeader(lower_case_header_name, header_iter.values())) {
            rejected = true;

            std::map<std::string, FlashNavigateUsage>::const_iterator iter =
                    rejected_headers.find(lower_case_header_name);
            FlashNavigateUsage usage =
                    iter != rejected_headers.end() ? iter->second : REJECT_OTHER_HEADERS;
            RecordFlashNavigateUsage(usage);
        }
    }

    RecordFlashNavigateUsage(TOTAL_NAVIGATE_REQUESTS);
    if (rejected) {
        RecordFlashNavigateUsage(TOTAL_REJECTED_NAVIGATE_REQUESTS);
        return PP_ERROR_NOACCESS;
    }

    // Navigate may call into Javascript (e.g. with a "javascript:" URL),
    // or do things like navigate away from the page, either one of which will
    // need to re-enter into the plugin. It is safe, because it is essentially
    // equivalent to NPN_GetURL, where Flash would expect re-entrancy.
    ppapi::proxy::HostDispatcher* host_dispatcher =
            ppapi::proxy::HostDispatcher::GetForInstance(pp_instance());
    host_dispatcher->set_allow_plugin_reentrancy();

    // Grab a weak pointer to ourselves on the stack so we can check if we are
    // still alive.
    base::WeakPtr<PepperFlashRendererHostQt> weak_ptr = weak_factory_.GetWeakPtr();
    // Keep track of reply contexts in case we are destroyed during a Navigate
    // call. Even if we are destroyed, we still need to send these replies to
    // unblock the plugin process.
    navigate_replies_.push_back(host_context->MakeReplyMessageContext());
    plugin_instance->Navigate(data, target.c_str(), from_user_action);
    // This object might have been destroyed by this point. If it is destroyed
    // the reply will be sent in the destructor. Otherwise send the reply here.
    if (weak_ptr.get()) {
        SendReply(navigate_replies_.back(), IPC::Message());
        navigate_replies_.pop_back();
    }

    // Return PP_OK_COMPLETIONPENDING so that no reply is automatically sent.
    return PP_OK_COMPLETIONPENDING;
}

int32_t PepperFlashRendererHostQt::OnIsRectTopmost(
        ppapi::host::HostMessageContext* host_context,
        const PP_Rect& rect)
{
    content::PepperPluginInstance* plugin_instance =
            host_->GetPluginInstance(pp_instance());
    if (plugin_instance &&
            plugin_instance->IsRectTopmost(
                gfx::Rect(
                    rect.point.x,
                    rect.point.y,
                    rect.size.width,
                    rect.size.height)))
        return PP_OK;
    return PP_ERROR_FAILED;
}

int32_t PepperFlashRendererHostQt::OnInvokePrinting(
        ppapi::host::HostMessageContext* host_context)
{
    return PP_ERROR_FAILED;
}

} //QtWebEngineCore
