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PONative Client plugin using tesseract library
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  1. PONative Client plugin using tesseract library
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    copied!<p>I'm trying to build a Native Client plugin for Chrome that will include the TesseractOCR library. I've compiled leptonica and tesseract (and appropriate dependencies) using the glibc NaCL toolchain for linux x86-64. All the dynamically-linked libraries are included in the nmf.</p> <p>When I actually try to load the plugin in chrome, I get the following error on the javascript console:</p> <pre><code>updateStatus() hello_tutorial.html:56 pageDidLoad if true hello_tutorial.html:39 NativeClient: NaCl module load failed: Nexe crashed during startup hello_tutorial.html:1 </code></pre> <p>I'm not sure if I've compiled something incorrectly or I'm attempting to do something that NaCL/Chrome can't handle. Any suggestions and help are greatly appreciated!</p> <p>I do get the LOADING... to display and such.</p> <p>I've disabled the nacl_gdb debugger in the Chrome flags (as suggested by <a href="https://groups.google.com/forum/?fromgroups#!topic/native-client-discuss/h-0RYn08WmE" rel="nofollow noreferrer">this post</a> and <a href="https://stackoverflow.com/questions/14191985/error-when-running-native-client-sdk-examples">this post</a>). I can compile and run the examples from the NaCL tutorials.</p> <p>This is the HTML file that loads the plugin:</p> <pre><code>&lt;!DOCTYPE html&gt; &lt;html&gt; &lt;!-- Copyright (c) 2012 The Native Client Authors. All rights reserved. Use of this source code is governed by a BSD-style license that can be found in the LICENSE file. --&gt; &lt;head&gt; &lt;title&gt;hello_tutorial&lt;/title&gt; &lt;script type="text/javascript"&gt; HelloTutorialModule = null; // Global application object. statusText = 'NO-STATUS'; // Indicate load success. function moduleDidLoad() { HelloTutorialModule = document.getElementById('hello_tutorial'); updateStatus('SUCCESS'); console.log("moduleDidLoad()"); } // The 'message' event handler. This handler is fired when the NaCl module // posts a message to the browser by calling PPB_Messaging.PostMessage() // (in C) or pp::Instance.PostMessage() (in C++). This implementation // simply displays the content of the message in an alert panel. function handleMessage(message_event) { alert(message_event.data); } // If the page loads before the Native Client module loads, then set the // status message indicating that the module is still loading. Otherwise, // do not change the status message. function pageDidLoad() { if (HelloTutorialModule == null) { updateStatus('LOADING...'); console.log("pageDidLoad if true"); } else { // It's possible that the Native Client module onload event fired // before the page's onload event. In this case, the status message // will reflect 'SUCCESS', but won't be displayed. This call will // display the current message. updateStatus(); console.log("pageDidLoad if false"); } } // Set the global status message. If the element with id 'statusField' // exists, then set its HTML to the status message as well. // opt_message The message test. If this is null or undefined, then // attempt to set the element with id 'statusField' to the value of // |statusText|. function updateStatus(opt_message) { console.log("updateStatus()"); if (opt_message) statusText = opt_message; var statusField = document.getElementById('status_field'); if (statusField) { if(statusField.innerHTML.indexOf("..." &gt;= 0)){ statusField.innerHTML = statusText.replace(".", ""); } else{ if(statusField.innerHTML.indexOf(".." &gt;= 0)){ statusField.innerHTML = statusText + "."; } else{ if(statusField.innerHTML.indexOf("." &gt;= 0)){ statusField.innerHTML = statusText + "."; } } } statusField.innerHTML = statusText; } } &lt;/script&gt; &lt;/head&gt; &lt;body onload="pageDidLoad()"&gt; &lt;h1&gt;Native Client Module HelloTutorial&lt;/h1&gt; &lt;p&gt; &lt;!-- Load the published .nexe. This includes the 'nacl' attribute which shows how to load multi-architecture modules. Each entry in the "nexes" object in the .nmf manifest file is a key-value pair: the key is the instruction set architecture ('x86-32', 'x86-64', etc.); the value is a URL for the desired NaCl module. To load the debug versions of your .nexes, set the 'nacl' attribute to the _dbg.nmf version of the manifest file. Note: Since this NaCl module does not use any real-estate in the browser, it's width and height are set to 0. Note: The &lt;EMBED&gt; element is wrapped inside a &lt;DIV&gt;, which has both a 'load' and a 'message' event listener attached. This wrapping method is used instead of attaching the event listeners directly to the &lt;EMBED&gt; element to ensure that the listeners are active before the NaCl module 'load' event fires. This also allows you to use PPB_Messaging.PostMessage() (in C) or pp::Instance.PostMessage() (in C++) from within the initialization code in your NaCl module. --&gt; &lt;div id="listener"&gt; &lt;script type="text/javascript"&gt; var listener = document.getElementById('listener'); listener.addEventListener('load', moduleDidLoad, true); listener.addEventListener('message', handleMessage, true); &lt;/script&gt; &lt;embed name="nacl_module" id="hello_tutorial" width=0 height=0 src="hello_tutorial.nmf" type="application/x-nacl" /&gt; &lt;/div&gt; &lt;/p&gt; &lt;h2&gt;Status&lt;/h2&gt; &lt;div id="status_field"&gt;NO-STATUS&lt;/div&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p>This is the C++ file I'm trying to compile for the plugin:</p> <pre><code>#include &lt;cstdio&gt; #include &lt;string&gt; #include "ppapi/cpp/instance.h" #include "ppapi/cpp/module.h" #include "ppapi/cpp/var.h" #include &lt;baseapi.h&gt; #include &lt;allheaders.h&gt; /// The Instance class. One of these exists for each instance of your NaCl /// module on the web page. The browser will ask the Module object to create /// a new Instance for each occurence of the &lt;embed&gt; tag that has these /// attributes: /// type="application/x-nacl" /// src="hello_tutorial.nmf" /// To communicate with the browser, you must override HandleMessage() for /// receiving messages from the browser, and use PostMessage() to send messages /// back to the browser. Note that this interface is asynchronous. class HelloTutorialInstance : public pp::Instance { public: /// The constructor creates the plugin-side instance. /// @param[in] instance the handle to the browser-side plugin instance. explicit HelloTutorialInstance(PP_Instance instance) : pp::Instance(instance) {} virtual ~HelloTutorialInstance() {} /// Handler for messages coming in from the browser via postMessage(). The /// @a var_message can contain anything: a JSON string; a string that encodes /// method names and arguments; etc. For example, you could use /// JSON.stringify in the browser to create a message that contains a method /// name and some parameters, something like this: /// var json_message = JSON.stringify({ "myMethod" : "3.14159" }); /// nacl_module.postMessage(json_message); /// On receipt of this message in @a var_message, you could parse the JSON to /// retrieve the method name, match it to a function call, and then call it /// with the parameter. /// @param[in] var_message The message posted by the browser. virtual void HandleMessage(const pp::Var&amp; var_message) { // TODO(sdk_user): 1. Make this function handle the incoming message. } }; /// The Module class. The browser calls the CreateInstance() method to create /// an instance of your NaCl module on the web page. The browser creates a new /// instance for each &lt;embed&gt; tag with type="application/x-nacl". class HelloTutorialModule : public pp::Module { public: HelloTutorialModule() : pp::Module() {} virtual ~HelloTutorialModule() {} /// Create and return a HelloTutorialInstance object. /// @param[in] instance The browser-side instance. /// @return the plugin-side instance. virtual pp::Instance* CreateInstance(PP_Instance instance) { return new HelloTutorialInstance(instance); } }; namespace pp { /// Factory function called by the browser when the module is first loaded. /// The browser keeps a singleton of this module. It calls the /// CreateInstance() method on the object you return to make instances. There /// is one instance per &lt;embed&gt; tag on the page. This is the main binding /// point for your NaCl module with the browser. Module* CreateModule() { return new HelloTutorialModule(); } } // namespace pp </code></pre> <p>The compiler command for it:</p> <pre><code>/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++ hello_tutorial.cc -o hello_tutorial_x86_64.nexe -I/var/www/native_client/projects/leptonica_src/src -I/var/www/native_client/projects/tesseract_build/include/tesseract -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include/glib-2.0 -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include/webp -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include/libpng12 -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include -I/var/www/native_client/projects/leptonica_src/src -I/var/www/native_client/nacl_sdk/pepper_26/include -L/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib -L/var/www/native_client/projects/leptonica_src/src/.libs -L/var/www/native_client/projects/tesseract_build/lib -lppapi_cpp -lppapi -pthread -lglib-2.0 -lstdc++ -ldl -lz -lwebp -lpng -ltesseract -llept -lnosys -lm </code></pre> <p>The commands I used to compile leptonica:</p> <pre><code>&gt; ./configure --host=nacl SOURCES="-I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include" AR="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/bin/ar" CC="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" CFLAGS=" -g -O2 -fPIC -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include/webp -I/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/include" CPP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++ -E" CXX="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" CXXCPP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++ -E" CXXFLAGS="-g -O2 -fPIC " LD="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-ld -L /var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib -lplatform -ldl" NM="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-nm -B" OBJDUMP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-objdump" RANLIB="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-ranlib" ac_ct_CXX="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" &gt; MAKE </code></pre> <p>Compiling Tesseract</p> <pre><code>&gt; ./configure --host=nacl --prefix=/var/www/native_client/projects/tesseract_build SOURCES="-I/var/www/native_client/projects/leptonica_src_compiled_x86-64/src" AR="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/bin/ar" CC="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" CFLAGS=" -g -O2 -fPIC -I/var/www/native_client/projects/leptonica_src_compiled_x86-64/src" CPP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++ -E" CXX="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" CXXCPP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++ -E" CXXFLAGS="-g -O2 -fPIC -I/var/www/native_client/projects/leptonica_src_compiled_x86-64/src" LD="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-ld -L/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib -L/var/www/native_client/projects/leptonica_src_compiled_x86-64/src/.libs -lplatform -ldl" LIBLEPT_HEADERSDIR="/var/www/native_client/projects/leptonica_src_compiled_x86-64/src" LIBS="-L/var/www/native_client/projects/leptonica_src/src/.libs -L/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib -llept -lpng -lwebp -lz" NM="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-nm -B" OBJDUMP="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-objdump" RANLIB="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-ranlib" ac_ct_CXX="/var/www/native_client/nacl_sdk/pepper_26/toolchain/linux_x86_glibc/bin/x86_64-nacl-g++" &gt; MAKE </code></pre>
 

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