Get DOM CSS properties by using headless Mozilla 
Mozilla July 10th, 2009
Project repository: http://git.lazytech.info/?p=dom-traversal.git
This program can run without X environment by using headless Mozilla back-end, and output DOM nodes’ CSS properties for web pages.
For headless Mozilla, see: http://chrislord.net/files/fosdem-09-slides.odp
For compiling: http://center.lazytech.info/wiki/OffscreenMozilla, http://center.lazytech.info/wiki/DOMTraversal
Output snippet for parsing www.google.com:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | <html> Style: html, div, map, dt, isindex, form { display: block; } <head> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <meta> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <title> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <script> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <style> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <script> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <style> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <style> Style: area, base, basefont, head, meta, script, style, title, noembed, param { display: none; } <body> Style: body { display: block; margin: 8px; } body, td, a, p, .h { font-family: arial,sans-serif; } <textarea> Style: display: none; textarea { margin: 1px 0pt; border: 2px inset threedface; background-color: -moz-field; color: -moz-fieldtext; font: medium -moz-fixed; text-rendering: optimizelegibility; text-align: start; text-transform: none; word-spacing: normal; letter-spacing: normal; vertical-align: text-bottom; cursor: text; -moz-binding: url("chrome://global/content/platformHTMLBindings.xml#textAreas"); -moz-appearance: textfield-multiline; text-indent: 0pt; -moz-user-select: text; text-shadow: none; word-wrap: break-word; } input:-moz-read-write, textarea:-moz-read-write { -moz-user-modify: read-write ! important; } <iframe> Style: display: none; iframe { border: 2px inset; } <div> Style: html, div, map, dt, isindex, form { display: block; } #gbar { height: 22px; } #gbar, #guser { font-size: 13px; padding-top: 1px ! important; } #gbar { float: left; } <nobr> Style: nobr { white-space: nowrap; } <b> Style: b, strong { font-weight: bolder; } .gb1, .gb3 { height: 22px; margin-right: 0.5em; vertical-align: top; } ...... |
It ate about 20M+ memory when running. To reduce the memory usage, maybe we should build it by using Mozilla’s DOM and Layout components only. It’s a hard work…
CHMReader compile issues on Mac
Mozilla June 8th, 2009
CHM Reader is a great extension make Firefox support .chm file, project host on：http://sourceforge.net/projects/chmreader/
When I compiled it on my OSX 10.5.7 occurred following issue:
1 2 3 | g++ -o components/mozCHMModule.os -c -fPIC -I/Users/duo/xulrunner-sdk/include -I/Users/duo/xulrunner-sdk/sdk/include components/mozCHMModule.cpp /Users/duo/xulrunner-sdk/sdk/include/nsStringAPI.h:1053: error: size of array 'arg' is negative scons: *** [components/mozCHMModule.os] Error 1 |
The line in nsStringAPI.h is PR_STATIC_ASSERT(sizeof(wchar_t) == 2), but 4-bytes is the default wide character size on macs, so we should add -fshort-wchar to compile flag options.
The other issue in link stage:
1 2 3 4 | g++ -o platform/Darwin_x86-gcc3/components/libchm.dylib -dynamiclib components/chm_lib.os components/lzx.os components/mozCHMModule.os components/mozCHMFile.os components/mozCHMUnitInfo.os components/mozCHMInputStream.os -L/Users/duo/xulrunner-sdk/lib -L/Users/duo/xulrunner-sdk/sdk/lib -lxpcom -lxpcomglue_s -lnspr4 -lplds4 -lplc4 ld: file not found: @executable_path/libsmime3.dylib collect2: ld returned 1 exit status scons: *** [platform/Darwin_x86-gcc3/components/libchm.dylib] Error 1 |
Just add -Wl,-executable_path -Wl,/path/to/gecko/sdk/bin to link flag options.
Complete svn diff result：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | Index: components/SConscript =================================================================== --- components/SConscript (revision 114) +++ components/SConscript (working copy) @@ -7,6 +7,8 @@ libs = ['xpcom', 'xpcomglue_s', 'nspr4', 'plds4', 'plc4'] +linkflags = '' + # We use firefox development files instead for geckosdk on FreeBSD if system() != 'FreeBSD': try: @@ -38,7 +40,8 @@ cpppath.append('/usr/include/nspr') elif system() == 'Darwin': - cxxflags = [] + cxxflags = ['-fshort-wchar'] + linkflags = ['-Wl,-executable_path', '-Wl,%s/bin' % geckosdk] elif system() == 'Windows': cxxflags = ['/D', 'WIN32', '/D', 'XP_WIN', '/nologo', '/MT', '/O2'] @@ -70,7 +73,7 @@ '/usr/local/lib/firefox3/sdk/lib'] env = Environment(CPPPATH = cpppath, LIBPATH = libpath, LIBS = libs, - CXXFLAGS= cxxflags) + CXXFLAGS= cxxflags, LINKFLAGS = linkflags) bxpt = Builder( action = 'xpidl -w -m typelib -Icomponents -I%s -I%s -e $TARGET $SOURCE' \ |
XPCOM: Javascript function call alternative
Mozilla May 31st, 2009
I have wrote a blog post about how to call JavaScript function from C++ XPCOM (XPCOM: Javascript function call), but just found another way to achieve this goal by observer mechanism.
C++ XPCOM code:
1 2 | nsCOMPtr<nsIObserverService> observerService = do_GetService("@mozilla.org/observer-service;1"); observerService->NotifyObservers(NULL, "ping", ToNewUnicode(NS_ConvertASCIItoUTF16("www.google.com"))); |
JavaScript code:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | const Cc = Components.classes; const Ci = Components.interfaces; var aObserver = { observe: function(subject, topic, data) { if (topic == "ping") { alert("Ping: " + data); } } }; var observerService = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService); observerService.addObserver(aObserver, "ping", false); |
In multithreading XPCOM, sometime we should call JavaScript function by nsIProxyObjectManager (JavaScript and UI are on a single thread, see nsISupports proxies and nsProxiedService.h for detail)
